5-31-19 Thousands of birds perished in the Bering Sea. Arctic warming may be to blame
Emaciated puffins and other birds washed ashore on an Alaskan island in unusually high numbers. Thousands of puffins and other seabirds in the Bering Sea appear to have died in the winter of 2016 to 2017. The birds look like they starved to death, but the ultimate culprit was probably climate change, scientists say. From October 2016 to January 2017, more than 350 dead birds, mostly tufted puffins, washed ashore at St. Paul Island, Alaska, on the Bering Sea. The birds were emaciated, and many had been molting when they perished. The period when birds regrow new coats of feathers is a particularly high-stress time for puffins and other birds because the animals need extra food while also being temporarily unable to fly. The condition of the birds’ bodies points to starvation as the cause of death, scientists led by Timothy Jones, a biologist at the University of Washington in Seattle, report May 29 in PLOS ONE. Based on wind speed and direction across the Bering Sea that fall and winter, as well as the number of carcasses that washed ashore on St. Paul Island, but not on a neighboring island, the researchers estimate that between 3,150 and 8,800 birds died during that period. The deaths are probably linked to elevated sea-surface temperatures in the eastern Bering Sea, a result of human-caused climate change, the team suggests. In the past, summertime sea ice melt has helped fuel blooms of plankton that form the base of the food web in the sea (SN: 3/16/19, p. 20). But sea ice has become scarce in the Bering Sea in the last few years, and there are fewer plankton blooms. That has had cascading effects through the sea's food web, including decreases in some species of small fish, such as capelin and herring, that puffins eat. Starvation may also have been responsible for recent mass die-offs of other seabirds in the region, such as of murres, auklets and kittiwakes.
5-31-19 GM fungus rapidly kills 99% of malaria mosquitoes, study suggests
A fungus - genetically enhanced to produce spider toxin - can rapidly kill huge numbers of the mosquitoes that spread malaria, a study suggests. Trials, which took place in Burkina Faso, showed mosquito populations collapsed by 99% within 45 days. The researchers say their aim is not to make the insects extinct but to help stop the spread of malaria. The disease, which is spread when female mosquitoes drink blood, kills more than 400,000 people per year. Worldwide, there are about 219 million cases of malaria each year. Conducting the study, researchers at the University of Maryland in the US - and the IRSS research institute in Burkina Faso - first identified a fungus called Metarhizium pingshaense, which naturally infects the Anopheles mosquitoes that spread malaria. The next stage was to enhance the fungus. "They're very malleable, you can genetically engineer them very easily," Prof Raymond St Leger, from the University of Maryland, told BBC News. They turned to a toxin found in the venom of a species of funnel-web spider in Australia. The genetic instructions for making the toxin were added to the fungus's own genetic code so it would start making the toxin once it was inside a mosquito. "A spider uses its fangs to pierce the skin of insects and inject toxins, we replaced the fangs of spider with Metarhizium," Prof St Leger explained. Laboratory tests showed the genetically modified fungus could kill quicker, and that it took fewer fungal spores to do the job. The next step was to test the fungus in as close to real-world conditions as possible. A 6,500-sq-ft fake village - complete with plants, huts, water sources and food for the mosquitoes - was set up in Burkina Faso. It was surrounded by a double layer of mosquito netting to prevent anything escaping.
5-30-19 A fungus weaponized with a spider toxin can kill malaria mosquitoes
In field trials, genetically engineered Metarhizium pingshaense reduced numbers of the insects. A fungus engineered to produce a spider toxin could help take down insecticide-resistant mosquitoes that can spread malaria. In a netted, outdoor experiment in Burkina Faso, the genetically engineered fungus wiped out mosquito populations within two generations, researchers report in the May 31 Science. If the result holds up in a real-world situation, the modified fungus may one day become a tool for controlling mosquitoes that can transmit the deadly disease. In 2017, an estimated 219 million people in 87 countries were infected with malaria, and 435,000 died, according to the World Health Organization. Africa carried most of the malaria burden, with 92 percent of cases and 93 percent of deaths occurring on the continent that year. The fungus Metarhizium pingshaense, long known to infect and kill mosquitoes, was made even deadlier to the insects by the addition of a gene that produces a spider bite toxin called Hybrid. Researchers engineered the fungus to make Hybrid in the presence of the mosquito version of blood, called hemolymph. “We’re just bypassing the spider fangs and getting the fungus to do the same job,” says study coauthor Raymond St. Leger, an entomologist at the University of Maryland in College Park. In laboratory trials in 2011, engineered fungi related to M. pingshaense infected and killed mosquitoes and their malaria parasites (SN Online: 2/25/11). (The fungi don’t harm people, other insects or animals.) “That’s all well and good, but what happens in the lab doesn’t necessarily translate into field conditions,” says study coauthor Brian
5-30-19 A type of African mole rat is immune to the pain caused by wasabi
If you hate wasabi-flavoured snacks, you are not alone. All things in the animal kingdom, down to worms and flies, naturally avoid allyl isothiocyanate (AITC), the compound responsible for wasabi’s pungent taste. But now researchers have discovered the first species immune to the burning pain caused by exposure to AITC, raising the prospect of new pain relief in humans and boosting our knowledge of evolution. The highveld mole rat (Cryptomys hottentotus pretoriae), which lives in the east of South Africa, proved completely insensitive to AITC when it was injected in its paw. The reason appears to be the similarity of AITC to the sting of the aggressive Natal droptail ant, which often live in the rats’ burrows. An international team concludes that over millions of years, the rat has developed a particularly high expression for a gene that blocked the channel through which it would feel pain from AITC. That immunity gives the highvelds an advantage over other African mole rat species, allowing them to survive in areas others would not enter because of their sensitivity to the ant’s sting. “Evolution over millions of years works like a blind watchmaker, of how to fix the problem,” says Gary Lewin of the Max Delbrück Center for Molecular Medicine, Germany. When his team used drugs to block the ‘short circuit’ protecting the rats from feeling the burn from AITC, they did react to the pain. The understanding of the genetic mechanism for turning off pain perception could help people in future too. “This could help develop a therapy to shut down pain in humans,” says Lewin. The rats are related to the ugly but exceptional naked mole-rat, which for years has been known to be immune to the pain caused by acid.
5-30-19 Wild bees' nest made entirely out of plastic discovered in Argentina
Plastic waste is just about everywhere on the planet at this point, and some animals have been found to adapt to our litterbug ways. In Argentina, scientists have made the first report of a bee’s nest made only out of plastic pieces. At the end of 2017 and beginning of 2018, Mariana Allasino of the National Agricultural Technology Institute in Argentina, and her team were studying chicory pollinators in San Juan. At the edges of the crops, they put out 63 trap nests made of wood with holes where bees can use material to build brood cells. These are similar in shape to the tubes in honeycomb and hold larvae while they develop. The team checked the trap nests monthly, finding only three nests. Two had brood cells made of petals and mud and were created by a species called Megachile jenseni. They confirmed this when five adults of the species emerged from the cells. The other nest was made entirely of two types of plastic – thin, blue strips the consistency of disposable shopping bags, and white pieces that were a bit thicker. In this nest, one brood cell had dead larva in it, one was empty and may have contained an unidentified adult that emerged, and one cell was unfinished. “I find it rather sad, but interesting. It begs for a choice test in an enclosure to determine why this plastic might be more appealing or adaptive than use of natural materials,” says Theresa Pitts-Singer at the US Department of Agriculture. She says it will be important to determine whether plastic lining in brood cells can be harmful to the bees, as more trapped moisture may lead to higher pathogen levels, and plastic may be toxic in some way as it breaks down.
5-30-19 Climate change link to puffin deaths
Climate change played a role in the deaths of thousands of puffins in Alaska, according to a study. Scientists believe the birds starved to death when the fish they eat migrated north with rising sea temperatures. The bodies of dead, emaciated puffins began washing up on beaches on Saint Paul Island in autumn 2016. Up to 9,000 puffins and other seabirds died over the course of a few months, US scientists say. And climate-driven shifts in fish populations, combined with the onset of moulting, may have caused this mass die-off. "Mass mortality events are increasing in frequency and magnitude, potentially linked with ongoing climate change," researchers led by Timothy Jones of the University of Washington, Seattle, wrote in the journal Plos One. The findings add to fears that rising temperatures are having unpredictable effects on birds, bats and other wildlife. A recent study found birds nesting in the Arctic faced a bigger risk of having their nests raided by predators due to changes linked to climate change. And over two days last November, record-breaking heat in Australia's north wiped out almost one-third of the nation's spectacled flying foxes, according to researchers. The latest study looked at tufted puffins breeding in the Bering Sea, off the coast of Alaska. The birds feed on fish and marine invertebrates, which in turn feed on ocean plankton. Scientists fear that unusually warm waters can shift the ocean food web, spelling trouble for marine life, including puffins. More than 350 bodies of seabirds were found on beaches on Saint Paul Island between October 2016 to January 2017. Most were tufted puffins but bodies of a second seabird, the Crested auklet, were also found.
5-29-19 Hundreds of puffins are starving to death because of climate change
Hundreds of “severely emaciated” puffin carcasses have washed ashore on an Alaskan island, and researchers believe thousands more have died at sea as warming waters continue to shrink their food supply. Between October 2016 and January 2017, inhabitants of St Paul Island in the Bering sea found the starved bodies of more than 350 seabirds, primarily tufted puffins. Analysing the location of bird carcasses and wind data, Timothy Jones at the University of Washington in Seattle and his colleagues estimated that between 3000 and 9000 birds died in total. When they examined some of the bodies, they found no signs of infection or unsafe levels of toxins. “Collected specimens were severely emaciated, suggesting starvation as the ultimate cause of mortality,” Jones wrote. Tufted puffins, which accounted for 79 per cent of the bird carcasses found, eat fish and marine invertebrates, which in turn eat phytoplankton. But changes to atmospheric conditions, including the ongoing heatwave, have massively disrupted the marine ecosystems, he wrote. There is less winter sea-ice, and warmer temperatures have been linked to fewer forage fish, crustaceans and other prey animals as they either die off or move north to cooler waters. Almost all the puffins they found were adults in the process of moulting, which makes them flightless for up to 40 days and requires more nutritional energy than normal. This combination of factors likely led to the huge numbers of deaths, Jones wrote. These mass deaths are increasing in frequency and magnitude, and two other largescale seabird die-offs in the region have been directly linked to a marine heatwave starting in 2013, Jones wrote.
5-28-19 African elephant poaching is falling at last - but it's still too high
The number of African elephants being slaughtered by poachers annually has more than halved, with the decline linked to waning Chinese demand for illegal ivory. South-east Asia’s burgeoning demand for illegal wildlife trade products saw elephant poaching surge in the late noughties, with mortality rates peaking at 10 per cent of the continent’s elephant population in 2011. But rates plummeted to around 4 per cent by 2017, or up to 15,000 elephants killed annually, an analysis of 53 sites across Africa found. The fall was closely correlated with a drop in demand, with the legal trade in mammoth ivory in China used as an indicator of the illegal trade in elephant ivory. Colin Beale at the University of York, a co-author on the study, says: “I think it is good news that the poaching rate is coming down. I don’t think they’ve come down enough.” Elephant populations can grow at around 5 per cent a year. But Beale says evidence suggests a 4 per cent poaching mortality rate is still too high for elephant numbers to be sustainable, because they can also die from natural factors such as drought and young elephants being killed by predators. Ofir Drori of the Eagle Network, which helps African governments with law enforcement, says such ‘desktop data’ of a reduction in poaching strongly contrasts with his experience in the field. “From fighting the trafficking networks on the ground I can say we see no signs of decline whatsoever, and rather a continued increase in levels of ivory trafficking.” The reported Africa-wide fall in poaching rates also masks big regional variations. The highest rates are in west and central Africa, while south and east Africa have very low rates. Botswana, which is renowned for low levels of corruption, has very little poaching. Forest elephants are suffering more than savannah elephants, because the heaviest poaching is taking place in forests.
5-27-19 Monkeys use their 'eagle' call to warn each other about drones
How do you teach a monkey new tricks? Lab trials have proved difficult places to train monkeys to distinguish between sounds and take different actions in response. But in the forests of Senegal’s Niokolo-Koba National Park, researchers were astonished at the speed one species of monkey adapted its behaviour to a new sound. Julia Fisher and her team flew drones over one community of green monkeys (Chlorocebus sabaeus) in the area, to see what they made of a new flying object in their environment. They responded instantly, making alarm calls to warn one another of the prospect of a new threat. The vocalisations were distinct from the ones they made in response to models of leopards and snakes, but almost identical to calls made by a related species of monkey in response to eagles. The results suggest a hard-wired response to the perception of an aerial threat and the use of that specific call. The monkeys adapted so quickly to the new noise that they began scanning the skies and making the calls even when played a sound of the drone from the ground. The monkeys were never seen issuing alarm calls to birds of prey in the area, suggesting the birds they usually see are not considered a threat. The drones, however, seemed to be perceived as dangerous. “It’s certainly disconcerting, unpredictable, something they’ve not seen before, so it makes sense to alert everybody,” says Fisher. She says she was “blown away” by how rapidly the monkeys appeared to learn. “The listeners are smart. It’s almost impossible to get a monkey in a lab to do an audio task.” It is not clear why such learning is harder in a lab environment, she says.
5-27-19 Where is the line between dog and wolf?
The answer isn't in their DNA. Living in the Canadian Rockies allows me ample opportunities to get out into nature. Just an hour outside the city, I can be within wilderness, with no cellphone reception and no other humans. Such wilderness, of course, comes with plenty of wildlife, including a number of contemporary North American canines such as coyotes and wolves. While I tend to go without any human company, I do have a canine companion, one taxonomically positioned within the species Canis familiaris but also bearing a proper name, Yuni, which distinguishes him as a particular individual apart from his species. Above the 42nd parallel, snow is plentiful in these parts of the Rockies, often starting to fall early in the autumn. While Yuni and I get out plenty in the summer, enjoying the relative warmth of the area, we are both in our element during the winter. Yuni is a Finnish Lapphund, a breed from northern Scandinavia; my ancestors are positioned within southern Scandinavia. Being out in the wild during winter affords me, a human, with rich visual signs present in the landscape. Yuni's cues are predominantly olfactory, though at times he also responds visually to the prints left on the ground. Sometimes, we stand paw-print to paw-print, wolf steps next to dog steps. We haven't come face to face with these wolves, but we sometimes listen to their howls in the near distance. Most of the common cultural representations that inform my human mind tell me that we should be very wary, even scared, in the presence of these wild canines. Within the domains of human culture, wolves are commonly evoked as predatory and aggressive. Some locals even inform me that Yuni and I could be torn apart at any moment. My dog certainly doesn't act with any fear in these situations. After all, his existence falls outside the domain of most, though certainly not all, human language games. His is also a dog variety bred for reindeer herding where part of the job is to protect the herd from predators.
5-23-19 The tiniest fish are the most important for healthy coral reefs
We have long overlooked many of the important inhabitants of coral reefs. Tiny fish that hide in the nooks and crannies may provide much of the food that supports larger animals on and around healthy coral reefs. “There are these whole worlds happening that people are just not aware of on coral reefs that involve these incredibly beautiful little fish,” says Isabelle Cote of Simon Fraser University in Canada. Efforts to conserve and restore coral reefs focus on the corals themselves and on larger fish, she says. For instance, no one thinks of providing the small-scale shelter the tiny fish need. Cote’s colleague Simon Brandl has been studying “cryptobenthic” reef fish that are less than 50 millimetres long as adults – basically, the ones you don’t see when snorkelling or diving on a reef. When he looked at surveys of plankton near reefs around the world, he was surprised to discover that 70 per cent of the fish larvae were of these cryptobenthic species. Larger fish produce more eggs overall than the tiny fish, says Cote. But these eggs have large yolks and float in the plankton for weeks. This allows the larvae to disperse over vast distances but relatively few make it back to reefs. By contrast, the eggs of tiny fish develop fast and the larvae stay near reefs, so they end up outnumbering the larvae of bigger fish. That means they are an important food source for other animals. In fact, when the team modelled what happens based on the available data, they concluded that that these tiny fish provide 60 per cent of all the fish biomass eaten on reefs. “There’s this massive turnover,” says Cote. In other words, the total biomass of these tiny fish at any one time is relatively small. But because these fish live fast and die young, they provide most of the eaten biomass over an entire year. The mortality rate can be as high as 70 per cent a week.
5-23-19 Chimpanzees eat tortoises after smashing them open on tree trunks
Tortoise meat is supposedly so delicious it has led people to eat some species to extinction. Evidently chimpanzees enjoy it too, as a group of these apes has figured out how to crack open tortoise shells to eat the meat within.. The chimps in question live in Loango National Park in Gabon, west Africa. They have only got used to humans within the last three years, so little is known about their behaviour. Between 2016 and 2018, Tobias Deschner at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany and his colleagues observed 38 incidents of chimps trying to eat hinge-back tortoises, all but four of them successful. When a chimp found a tortoise, it picked it up and started hitting its underside – which is softer than the tough shell on its back – against a hard surface like a tree trunk. Once the tortoise had been cracked open, the chimp climbed into a tree to eat it. On one occasion, the group’s alpha male ate half a tortoise, then wedged the remainder into the fork of a tree and slept overnight in a nearby nest. He then returned the next day and ate the rest. The chimps only ate tortoises during the main dry season from May to October, when other food was plentiful. The tortoises may simply be easier to find then, says Deschner. “During the dry season the leaves are really dry, and then it’s amazing how much noise a tortoise can make just by moving around,” he says. Other groups of chimpanzees have devised other tools, such as using sticks to “fish” for termites and spear bush-babies, and using moss as a sponge to drink water. It is not clear why chimps in other groups, some of them studied for decades, do not eat tortoises. The reptiles are widespread in Africa, so availability is not the issue.
5-22-19 Lyme disease is spreading across the US but your dog can help track it
As the climate warms, Lyme disease is spreading. To assess the risk of catching the infection in new areas, we need to be able to track the ticks that carry it. Now an analysis of veterinary records suggests dogs are the answer. Lyme disease can lead to heart failure or paralysis but we don’t monitor how many people come into contact with the bacterium that causes it. “We don’t screen ourselves for exposure,” says Jenna Gettings at the University of Georgia. “The only time people are tested for tick-borne disease is when they have symptoms. Whereas with dogs, we screen healthy animals.” In the US, pet dogs are tested for Lyme disease at yearly health checks, and their data is reported to a central database. It’s currently possible to share veterinary records widely, as these don’t have the same kinds of privacy concerns as human health data, says Gettings. She and her colleagues analysed data from more than 16.5 million dog screening test results from 2012 to 2016. The test detects if dogs have produced antibodies to Borrelia burgdorferi, the Lyme-causing bacterium that can be passed to animals and people in tick bites. Because dogs tend to go to the same places as their owners, their data should reveal where people are at the most risk of contracting the disease. When the team compared the dog data with the reported rates of Lyme disease in humans during the same five-year period, they found an association between the two. In counties where 0 to 10 per cent of dogs screened positive for B. burgdorfei exposure, there was a rapid increase in human incidences of Lyme disease.
5-22-19 Some plants use hairy roots and acid to access nutrients in rock
Fine hairs and chemicals that dissolve rocky substrates are crucial in regions with little soil. No soil? No problem. Some herbaceous shrubs living on rocky mountains in Brazil use roots equipped with fine hairs and acids to dissolve rocks and extract the key nutrient phosphorus. The discovery, published in the May Functional Ecology, helps explain how a variety of plants can survive in impoverished environments. “While most people tend to view nutrient-poor environments as less diverse, they are actually very diverse because plants use diverse ways to get nutrients,” says coauthor Patricia de Britto Costa, a plant ecologist at the University of Campinas in Brazil. She and other colleagues in Brazil and Australia investigated how shallow-soil regions called campos rupestres in Portuguese, or rocky grasslands, can sustain more than an estimated 5,000 plant species — 15 percent of Brazil’s vascular plant diversity — despite occupying less than 1 percent of the country’s land area. What soil there is in these regions is poor, with nearly undetectable levels of the nutrients that plants need. And some plants manage to survive on rocky patches with no soil. Researchers used chisels and hammers to dig up the plants. “We found the roots growing into the rocks,” at least 10 centimeters deep, says coauthor Anna Abrahão, a plant ecologist now at the University of Hohenheim in Stuttgart, Germany. “The roots go deeper, and we always lose some of them.”
5-21-19 Chimps that mash potatoes challenge our understanding of tool use
Chimps have spontaneously figured out how to use a stick to mash a potato. The finding could prompt a rethink of how tool use develops in primate societies. Wild chimpanzees in Guinea climb palm trees to eat the trees’ “hearts”, which look like white asparagus. They use sticks to mash the hearts before eating them, like cooks using pestles and mortars. Chimps elsewhere don’t do this, suggesting that the behaviour is cultural and that Guinea chimps pick it up by copying each other. However, Claudio Tennie of the University of Tübingen in Germany is sceptical about copying. Many studies have demonstrated copying among chimps by showing them how to get food out of a puzzle box and seeing if they can then do it. Tennie says these studies are flawed because the chimps may simply be grasping how such boxes work and then figuring out how to open them themselves. To see whether chimps can work out such tricks on their own, Tennie and his colleague Elisa Bandini studied semi-wild chimps at the Chimfunshi Wildlife Orphanage in Zambia. The chimps had never seen stick-pounding. Bandini and Tennie gave them potatoes that had been boiled for 3 minutes: long enough to be edible, but still hard to eat. In three out of four groups, one chimp collected a stick and used it to mash the potato (American Journal of Primatology). “They redevelop these kind of behaviours on their own from scratch,” says Tennie. In a separate study involving Tennie, captive chimps figured out how to use sticks to dig up underground tubers, without ever having seen it done (PLoS ONE).
5-21-19 Putting a bird feeder in your garden really does help wildlife
Putting bird feeders in your garden really does help, according to a UK study looking at the growth of bird populations in the past 40 years. “We know that feeding happens on a huge scale in the UK, US, Australia and parts of Europe,” says Kate Plummer of the British Trust for Ornithology. “We are trying to understand what the impacts of that might be.” Volunteers for the trust have been monitoring which species feed on the food they put out in their gardens since the 1970s. Plummer’s team analysed this data to see what changes there have been over time. “There’s about 68 or so species that have always used feeders. They used them in the 70s and they use them now,” Plummer says. “But actually within our own gardens we are seeing a greater number of species.” For instance, just 10 per cent of volunteers saw wood pigeons and chaffinches at their feeders in the 1970s. Now they are seen at feeders in more than 80 per cent of gardens, alongside other birds that have always been common visitors, such as robins, blackbirds and blue tits. The team found this greater diversity rose in tandem with the increasing diversity of foods and of feeder types introduced over the decades, as revealed by adverts in bird magazines. Finally, the team compared its findings with survey data on bird populations. It could be, for instance, that increases in population sizes have led to increases in feeder use rather than vice versa. But because in urban areas the populations of birds that don’t use feeders haven’t increased while those that do have, the team thinks the feeding is driving the increases in populations.
5-21-19 Tiger sharks feast on migratory birds that fall out of the sky
Other marine animals don’t appear to target land birds that end up in the Gulf of Mexico. It all started when a small tiger shark barfed up a bunch of feathers. Marcus Drymon, a fisheries ecologist at Mississippi State University in Biloxi, had been catching sharks as part of a long-term shark monitoring program in the north-central Gulf of Mexico. Typically, a shark spent only about 90 seconds out of the water, enough time for scientists to weigh and tag it before releasing it. But one day in 2010, a tiger shark, perhaps stressed by the experience, left its stomach contents on the boat’s deck. “Being the science nerd I am, I scooped up all the feathers, all [that] tiger shark barf, and put it in a bag and took it back to the lab,” Drymon says. Little did he know that those stomach contents would lead to a discovery about how young tiger sharks take advantage of bird migrations to get a free meal. First, Drymon wanted to know what bird species the feathers had come from. So he reached out to an old friend, molecular ecologist Kevin Feldheim of the Field Museum in Chicago. Feldheim usually looks at shark DNA to study relationships between individual sharks. But he agreed to try to identify the feathers with DNA barcoding, a technique that lets scientists identify a species based on a short strand of mitochondrial DNA. The analysis showed that the feathers came from a brown thresher, a type of terrestrial songbird. Intrigued, Drymon searched the scientific literature, finding a handful of reports of tiger sharks eating terrestrial birds, and he decided to investigate how prevalent these meals were.
5-20-19 Bonobo mothers stand guard and chase off rivals while their sons mate
If your mum gets too involved in your love life, spare a thought for bonobos. Females of these great apes, which are closely related to chimpanzees, help their sons with hook-ups, guard the young lovers while they mate, and even haul rival males off females mid-sex. And it’s a strategy that works. Males whose mothers are in their group have three times the number of babies as those who don’t. It’s a strategy that’s akin to the “grandmother hypothesis” in humans, which says that older women can boost their reproductive success by helping their daughters rear children rather than having more offspring of their own. “Female bonobos can increase their fitness even if they don’t reproduce any more — but not through daughters, it’s through their sons,” says Martin Surbeck of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. Bonobos have an unusual social structure in that the top-ranking individuals are female, and sons usually stay with their mothers while young females leave to find new groups. These apes are also famed for having lots of sex, for social reasons, as well as reproduction. It happens whether or not females are fertile — although when they are fertile they are more desirable. Surbecks’ team has previously described the bonobo mothers’ over-involvement in their sons’ love lives while following a community of 35 animals in the Salonga National Park in the Democratic Republic of Congo. They found mating attempts are often disturbed by others, but mothers tend to hang around their sons and stop any such meddling. “If your son is copulating and another male tries to interfere, you chase this male away,” says Surbeck.
5-20-19 Bad moods could be contagious among ravens
The birds seem to pick up on and share negative emotions, but not positive ones. Here’s a downer: Pessimism seems contagious among ravens. But positivity? Not so much. When ravens saw fellow birds’ responses to a disliked food, but not the food itself, their interest in their own food options waned, researchers report May 20 in the Proceedings of the National Academy of Sciences. The study suggests that the birds pick up on and even share negative emotions, the researchers say. Ravens are “very good problem solvers … but this paper’s really highlighting their social intelligence as well,” says Andrew Gallup, a psychologist at SUNY Polytechnic Institute in Utica, N.Y., who was not involved in the study. The work paints a richer picture of how the birds’ brains work, he says. Known for their smarts, ravens act in ways that suggest a capacity for empathy, such as by appearing to console a distressed comrade. Thomas Bugnyar, a cognitive ethologist at the University of Vienna, and his colleagues wanted to look into one building block of empathy — whether animals share emotions. To be able to feel for others, an animal needs to be able to feel like others, he says. But sizing up an animal’s mood is tricky. Scientists generally rely on behavioral or physiological cues to clue into a creature’s emotional state. More challenging is assessing how one animal’s mood might influence another’s: Similar actions appearing to stem from kindred emotions may just be mimicry. To tune into the moods of ravens, the researchers set up experiments to watch whether the birds reacted positively or negatively to a neutral stimulus. This so-called cognitive bias test, used on a wide variety of animals from bees to pigs, “is basically … asking how you would judge a glass — if it’s half full or half empty,” Bugnyar says.
5-20-19 Is there a problem with salmon farming?
David Ainsley runs a tour company, taking tourists on his boat to experience the beauty of the west coast of Scotland. He is also a marine biologist and a diver and over the past eight years he has filmed the seabed next to a fish farm in Loch Shuna. Campaigners like him claim the feed, faeces and chemicals from salmon farms fall through the nets, killing the marine life underneath. The industry says it is focused on sustainability. The Scottish Environment Protection Agency (Sepa) is introducing tougher regulations.
5-20-19 Scientists: Why we should appreciate wasps
Scientists have put together a map of the UK's wasp population, showing the distribution of key species. Data recorded by volunteers gives an insight into where wasps are living in the nation's grasslands, woodlands and towns. The researchers say wasps are a much maligned insect, which deserve more attention. Rather than being "bothersome and pointless", they are in fact beneficial insects, keeping other pests in check. Dr Seirian Sumner of University College London said wasps are nature's pest controllers and a world without wasps would mean that we would have to use a lot more pesticides to control the other insects that we dislike and find annoying. "They're the maligned insect of the insect world - they're viewed as the gangsters, " she told the BBC. "Whereas actually we should be viewing them as a beneficial insect - they're doing us a favour, and we're just completely overlooking that favour." Dr Sumner and Prof Adam Hart of the University of Gloucestershire came up with the idea of the "Big Wasp Survey", to draw attention to wasps and their role in the natural world. A total of 2,000 people took part in the two-week citizen science project in late summer 2017, sending in more than 6,000 wasp samples for identification. The findings were used to draw up a map showing the distribution of common wasps and hornets, and how they vary across the UK. The German wasp (Vespula germanica) and the common yellowjacket wasp (Vespula vulgaris) were the most common species (both representing 44%). The European hornet (Vespa crabro) made up 6%, while two rarer species were also found.
5-18-19 Compassionate conservation is 'seriously flawed'
The idea that you cannot kill any animal is "fatally flawed" as a conservation concept, scientists argue. Conservation measures should concentrate on species or habitats rather than individual animals, they observe. Invasive species, they argue, often require mass culling of an animal in order to protect an endangered species. Under so called "compassionate conservation", such an approach would not be allowed. "The argument is that conservation and sustainability needs a variety of approaches. You need to be pluralistic about both the cultural and scientific approaches," explained study co-author Prof Kartik Shanker from the Indian Institute of Science. "There is universal agreement that animal welfare is important by which we mean that we should aim to reduce cruelty to animals and this applies to both wild biodiversity and domestic animals. Prof Shanker said there was agreement that cruelty should be minimised. "I think the problem arises when compassionate conservation states that you should not kill animals for any reason whatsoever," he told BBC News. Prof Shanker and his team of co-authors referred to a paper published last year that outlined a framework for compassionate conservation. They said that it had four key tenets: Do not harm, Individuals matter, Inclusivity, and Peaceful co-existence. The team challenged the "no kill" philosophy of this paper. They wrote: "Our view is that compassionate conservation… is seriously flawed. Compassion need not preclude humanely killing an animal if that reduces the animal's suffering, enhances the survival of the species or its habitat, or safeguards human life or other more threatened species."
5-17-19 Sea otters are bouncing back - and into the jaws of great white sharks
Decades of conservation work have boosted sea otter populations in many parts of the North Pacific, but the animals are now being killed by great white sharks. The sharks aren’t actually trying to eat the otters, preferring calorie-dense, blubbery prey like seals and sea lions. The bites are merely investigative, with sharks recoiling with a mouth of fur instead of a fatty meal. But such bites often cause mortal injuries to the otters, and they’re now happening more often off California’s beaches. After seeing a growing trend in the number of dead, bitten sea otters being washed ashore, Jerry Moxley, at the Monterey Bay Aquarium, and his colleagues set out to investigate where and when these bites were happening. The team compiled data on the seasonal movements of sharks and their preferred prey, elephant seals, as well as data on strandings of bitten otters. They used this information to compare the timing of shark bites on prey as well as mistargeted species – otters and humans. They found that sea otters were being bitten more frequently in the summer, around the time adult sharks come closer to shore before moving on to seal rookeries. This is also when humans are most often mistakenly targeted. The researchers think the sharks, low on fat reserves after their migration from feeding grounds hundreds of kilometers out into the Pacific, are less discriminating towards any seal-shaped animals they encounter. Moxley and his team also found that it was mostly intrepid young and male otters that fell victim to sharks. “The males and younger otters are more pioneering—more likely to venture into new territory beyond the denser kelp cover in the otters’ core range,” says Moxley.
5-17-19 No, koalas are not 'functionally extinct', but they are in trouble
Who has said koalas are “functionally extinct”? The Australian Koala Foundation, which lobbies for the animals’ protection, has put out a press release stating that it “believes koalas may be functionally extinct in the entire landscape of Australia”. The release triggered a flurry of worried headlines. So are they? No, although many populations of koalas are falling sharply due to habitat loss and global warming. Could they go extinct? There is no danger of koalas going extinct in Australia overall, says biologist Christine Adams-Hosking of the University of Queensland, who has studied the marsupials’ plight. “But at the rate of habitat clearing that is going on, we are going to see increased local population extinctions,” she says. Why has the AKF made this claim now? The claim was made on the eve of elections in Australia in which environmental issues such as climate change have become a big issue. The AFK has called on politicians to act. “There’s a lot of politics going on, and somehow the koala gets involved,” says Adams-Hosking. What does functionally extinct even mean? The term is used in several different senses. It can mean that a species has declined to a point where it can no longer plays the role it once did in a ecosystem, with significant effects on that ecosystem. Some define it even more narrowly, saying a species is functionally extinct when its decline leads to the extinction of other species. That’s not what we’re talking about here. There are more meanings? Yes. Others use it – arguably incorrectly – to describe a species that is probably extinct but we can’t be sure. For instance, when researchers failed to find any river dolphins in China in 2006, they declared the baiji “functionally extinct”.
5-17-19 Vaccines may help bats fight white nose syndrome
Oral inoculation would spread from bat to bat through nuzzles. Oral vaccines could give wild bats a better chance at surviving white nose syndrome, the fungal disease that has ravaged bat colonies in North America. In lab tests conducted on captured little brown bats, vaccination led to fewer infected bats developing lesions and more of the bats surviving, researchers report May 1 Scientific Reports. White nose syndrome, caused by the fungus Pseudogymnoascus destructans, has killed around 7 million bats in the United States since 2006. In some regions, the disease cut some bat colonies by 75 percent. The white fuzz grows across bats’ skin when the animals hibernate, eventually making them wake up, fly around and waste energy needed to survive winter (SN Online: 1/29/16). “It’s just devastating to some bat populations,” says veterinarian Elizabeth Falendysz at the U.S. Geological Survey National Wildlife Health Center in Madison, Wisc. Falendysz and colleagues made two vaccines against the fungus by implanting raccoon poxviruses with DNA instructions for making one of two fungal proteins, in order to trick the bats’ immune system into recognizing and fighting the fungus. (Vaccines that helped in rabies eradication efforts and in fighting plague in prairie dogs rely on the same mechanism.) Wild little brown bats (Myotis lucifugus) were vaccinated before being exposed to the fungus. Of 10 bats given a combination of both vaccines, only one developed lesions within the experiment’s 100-day hibernation period. Because little brown bats don’t do well in captivity, the team struggled with dwindling sample sizes, so it was hard to compare these numbers to other individual treatments. But 14 of the other 23 bats, or 61 percent, that didn’t get this vaccine combo developed lesions.
5-16-19 Squished faces aren’t the only cause of bulldog breathing difficulties
Many English and French bulldogs develop breathing difficulties, and the flat faces of these breeds have long been thought to be responsible, but now a gene mutation in these dogs suggests that face shape isn’t the only culprit. Jeffrey Schoenebeck at the University of Edinburgh, UK, and his colleagues have found a mutation in a gene called ADAMTS3, which is also present in Norwich terriers. Norwich terriers often suffer from similar breathing problems even though they have proportional noses. The team analysed DNA from more than 400 Norwich terriers, and also checked the dogs’ airways for signs of disease. The team found a significant association between the gene mutation and the likelihood of a Norwich terrier having a breathing problem called upper airway syndrome. “Mutation in the gene affects development and maintenance of the lymphatic system,” says Schoenebeck. In humans, the gene mutation is associated with fluid retention and swelling. The team thought that dogs with the gene could be predisposed to swelling in the upper airways that may result in breathing problems, so went on to check other breeds. Of the 24 English bulldogs the team analysed, 19 were found to have two copies of the mutated gene, while of 99 French bulldogs the team looked at, 17 carried one copy of the gene while three had two mutated copies. Skull shape is still a contributing factor to the breathing problems common in English bulldogs, French bulldogs and also pugs, says Schoenebeck. Because of their squished faces, they have a disproportionate amount of soft tissue around their nostrils, which affects air flow. Schoenebeck says the mutation could be used to develop genetic screening tests for breeders.
5-16-19 Some dog breeds may have trouble breathing because of a mutated gene
Norwich terriers don’t have flat snouts, but can suffer the same wheezing as bulldogs. Dogs with flat faces aren’t alone in their struggle to breathe. It turns out that Norwich terriers can develop the same wheezing — caused not by the shape of their snouts, but possibly by a wayward gene. DNA from 401 Norwich terriers revealed that those suffering a respiratory tract disorder shared the same variant of gene ADAMTS3 that’s associated with swelling around airways. Nearly a third of the dogs had two copies of that mutated gene. And those same dogs scored worse on airway-function tests than dogs with just one copy or the normal versions of the gene, researchers report online May 16 in PLOS Genetics. The gene variant, which does not hinder the gene’s main function in the development of lymphatic vessels, also turned up in the DNA of French and English bulldogs. That finding indicates that those pooches’ smooshed snouts might not be the only factor behind their labored breaths. “This is the first evidence to show that it’s not just all about skull shape,” says study coauthor Jeffrey Schoenebeck, an animal geneticist at the University of Edinburgh’s Roslin Institute. The research might someday help dog breeders build healthier pups. Schoenebeck suggests that a genetic test could be developed to identify Norwich terriers with the genetic variant. Breeders could then use the test to keep those dogs from reproducing and passing the mutation along.
5-16-19 Bloodthirsty bedbugs have feasted on prey for 100 million years
New genetic analyses reveal the insects evolved from at least the Cretaceous. The first bedbug infestations may have occurred in the beds of Cretaceous critters. Scientists previously assumed bloodsuckers’ first hosts were bats. But a new genetic analysis of 34 bedbug species reveals that bedbugs appeared 30 million to 50 million years before the nocturnal mammals, says Michael Siva-Jothy, an evolutionary biologist at the University of Sheffield in England, and his colleagues. The analysis, published online May 16 in Current Biology, pegs the emergence of ancient bedbugs at more than 100 million years ago. It also fleshes out more of the pests’ history. For instance, two bedbug species that humans are most familiar with didn’t evolve just to plague us. The common bedbug (Cimex lectularius) and the tropical bedbug (C. hemipterus) emerged around 47 million years ago, long before early human ancestors meandered into bedbug-infested caves, the team found (SN Online: 4/10/17). The new study “puts the Cimicidae family on the map in terms of understanding its diversity, understanding its evolutionary history in a way that no other previous studies had,” says Zach Adelman, a molecular geneticist at Texas A&M University in College Station, who was not involved in the study. To build a collection of bedbug specimens, a global network of scientists plucked insects from damp caves and dusty museum exhibits over 15 years. For each species, researchers looked at four genes known to mutate at a constant rate, like an evolutionary timekeeper. The team then calibrated that data with the known fossil records from two insects — an ancient species of bedbug and a closely related insect species — to create its timeline.
5-16-19 Bedbugs survived the dinosaur extinction event
A study that began as an investigation into the "utterly bizarre" way in which bedbugs reproduce has revealed they have existed for far longer than humans. DNA samples from 30 species of bedbug revealed the insects had been around for at least 115 million years. The blood-sucking parasites predate their earliest known hosts - bats - by more than 50 million years. The surprising finding is published in the journal Current Biology. Prof Mike Siva-Jothy, from the University of Sheffield's department of animal and plant sciences, who was part of the research team, said its initial investigation had been into what is known as "traumatic insemination". Male bedbugs have a dagger-like penis, with which they stab the female to inseminate directly into her bloodstream."It's the reproductive version of peacock's tail - it's so extreme," said Prof Siva-Jothy. "These animals are so strange - they don't do anything like any other animal does."It took 15 people 15 years to gather all the genetic samples, because these creatures are so cryptic." Most species the researcher sought out were hidden away in remote caves, where they feed on their bat hosts. But once the team had samples from enough different species, they were able to build their genetic bedbug timeline - mutations that occur spontaneously in the creatures' genetic code act like a molecular clock, allowing the scientists to trace the bugs' evolution back through millions of years. Dr Steffen Roth, from the University Museum Bergen, in Norway, who led the study, said: "The first big surprise we found was that bedbugs are much older than bats, which everyone assumed to be their first host. "Although, we don't yet know what their host was at the time when T. rex walked the Earth."
5-14-19 Peacock spiders’ superblack spots reflect just 0.5 percent of light
New images reveal microscopic structures that manipulate light to create the dark patches. Male peacock spiders know how to put on a show for potential mates, with dancing and a bit of optical trickery. Microscopic bumps on the arachnids’ exoskeletons make velvety black areas look darker than a typical black by manipulating light. This architecture reflects less than 0.5 percent of light, researchers report May 15 in the Proceedings of the Royal Society B. The ultradark spots, found near vivid colors on the spiders’ abdomens, create an “optical illusion that the colors are so bright … they're practically glowing,” says Harvard University evolutionary biologist Dakota McCoy. Male peacock spiders swing and shake their brilliantly colored abdomens during elaborate mating displays. Pigments produce the red and yellow hues, but blues and purples come from light interacting with hairlike scales (SN: 09/17/16, p. 32). Black areas on the spiders contain pigment, too. But scanning electron microscopy also revealed a landscape of tiny bumps in superblack patches on Maratus speciosus and M. karrie peacock spiders. In contrast, all-black, closely related Cylistella spiders have a smooth texture. Scanning electron microscope images show bumps, which manipulate incoming light, in superblack patches on the abdomens of two species of peacock spiders. While Maratus speciosus (left) has only bumps, M. karrie (middle) also sports spiky scales that limit reflection by scattering and absorbing light. A Cylistella spider (right) has a smoother surface, which results in an ordinary black appearance.
5-13-19 Mariana Trench: Deepest ocean 'teems with microbes'
The deepest place in the ocean is teeming with microscopic life, a study suggests. An international team of scientists found that the very bottom of the Mariana Trench, which lies almost 11km (7 miles) down in the Pacific Ocean, had high levels of microbial activity. The research is published in the journal Nature Geoscience. The underwater canyon was once thought to be too hostile an environment for life to exist. But this study adds to a growing body of evidence that a range of creatures can cope with the near-freezing temperatures, immense pressures and complete darkness. Dr Robert Turnewitsch, one of the authors of the paper from the Scottish Association for Marine Science, said: "The deepest parts of the deep sea are certainly not dead zones." In 2010, the scientists sent an unmanned submersible down into the vast underwater canyon, where it collected samples of the murky sediment that cakes the sea floor. An analysis of the levels of oxygen in the sample revealed the presence of a large number of microbes. Dr Turnewitsch explained: "These microbes, they respire as we do. And this oxygen consumption is an indirect measurement of the activity of the community." Surprisingly, these primitive, single-celled organisms were twice as active at the bottom of the trench than they were at a nearby 6km-deep (four miles) site.They were feasting on a plentiful supply of dead plants and creatures that had drifted down from the sea surface, the decomposing matter becoming trapped within the steep walls of the trench. "The amount of food down there and also the relative freshness of the material is surprisingly high - it seems to be surprisingly nutritious," said Dr Turnewitsch. The level of material found at the bottom of the trench was so high that it suggests the Mariana Trench - which is in an area of the ocean known as the Hadal zone - could play a key part in the carbon cycle and therefore in regulating the planet's climate. Dr Richard Turnewitsch said: "The fact that large amounts of organic matter that contain the carbon accumulate and are focused in these trenches also means they play an important role in the removal of carbon from the ocean and the overlying atmosphere. "The Hadal trenches may play a more important role in the global marine carbon cycle than was previously thought."
5-11-19 Animal cruelty sentencing: Just 8% of convicts jailed
Fewer than one in 10 people convicted of animal cruelty offences in Wales in the last decade have been jailed, research by BBC Wales shows. Last year, a man from Caerphilly avoided jail after he was convicted of having sex with his two dogs. The maximum custodial sentence for animal cruelty in England and Wales - six months - is the lowest in Europe. Magistrates "treat each individual case on its merits", the chairman of the Magistrates' Association said. Just 102 of the 1,268 convictions for animal cruelty offences in courts in Wales - 8% - resulted in a custodial sentence between 2007 and 2017, an analysis of Ministry of Justice figures reveals. And there has been a significant decline in the number of custodial sentences issued by courts in Wales - from a peak of 17 in 2011, to just six in 2017 - despite animal cruelty cases being at a five-year high. Responding to the figures, the RSPCA has called for tougher sentencing. But the BBC has found that only two maximum six-month sentences were issued by Welsh courts in the past decade. A Caerphilly man who was caught having sex with his two dogs avoided prison and was banned from keeping animals for 10 years. Robert Gwynn, 60, received a three-month suspended sentence last May after his neighbours witnessed the him committing the "disgusting and horrific" acts against his own dogs, Taff and Ben. In another case prosecuted by the RSPCA, a Merthyr Tydfil cat owner spoke of his horror when he discovered CCTV footage of his cat being intentionally set upon and mauled to death by a dog. Two boys, aged 15 and 17, were sentenced to a 12-month referral order to the youth offending team and were banned from keeping animals for 10 years after admitting causing unnecessary suffering.
5-10-19 Deep-sea fishes’ eye chemistry might let them see colors in near darkness
Proteins found in eye rod cells suggest deep-sea sight may be more than just shades of gray. Some fishes in the deep, dark sea may see their world in more than just shades of gray. A survey of 101 fish species reveals that four from the deep sea had a surprising number of genes for light-sensitive eye proteins called rod opsins, researchers report in the May 10 Science. Depending on how the animals use those light catchers, the discovery might challenge the widespread idea that deep-sea fishes don’t see color, says coauthor Zuzana Musilová, an evolutionary biologist at Charles University in Prague. To see, many fishes, humans and most other vertebrates rely on two types of light-detecting cells in the eye known as rods and cones. Cone cells use two or more kinds of opsins and need decent amounts of light to work. Rods generally use only one opsin called RH1, which works in dim light. That variety in opsins in cones, but not in rods, lets vertebrates see a range of colors in well-lit conditions but be color-blind in the near dark. In the new study, Musilová and Fabio Cortesi of the University of Queensland in Brisbane, Australia sailed on research ships equipped to reach into the ocean depths for fish. The deep-sea specimens came from the “twilight” zone 200 to 1,000 meters below the surface, where sunlight becomes only a subtle lessening of darkness. The most colorful things to look at would be bioluminescent spots on animals’ bodies.
5-10-19 Climate change: How frogs could vanish from ponds
Climate change is having an impact on frogs found in British ponds, research suggests. A deadly frog disease is spreading due to warmer temperatures and in the next 50 years could cause entire populations to vanish, according to a study. The virus could spell disaster for the common frog, which is a familiar sight in garden ponds and the countryside. Amphibians have been particularly hard hit by changes in the natural world. Four out of 10 species are on the edge of extinction globally due to factors such as disease, habitat loss and climate change. The study provides "strong evidence" of the impact of climate change on wildlife disease and how it might aid the spread of the virus across the UK, said Dr Stephen Price of ZSL's Institute of Zoology. "Climate change isn't something that's just happening in faraway places - it's something real and present that's already had hard-to-predict impacts on wildlife in our own back gardens here in the UK," he said. The prospect of entire populations of frogs being wiped out is "a real sadness" given the fond memories many people have of pond dipping and collecting tadpoles, he added. The research looked at a disease known as ranavirus, which can kill a large number of frogs in a short time. It found mass die-offs matched historic temperature changes, with outbreaks predicted to become more severe, widespread and over a greater proportion of the year within the next few decades, if carbon emissions continue unchecked. At present, the disease is confined largely to England, but climate change could lead to outbreaks across the UK and earlier in the year. If the disease were to hit tadpoles in spring, then whole populations could disappear "almost overnight", said the researchers.
5-9-19 Some deep-sea fish have evolved souped-up colour night vision
Fish living in the deep ocean have evolved highly-sensitive eyes that can see a range of colour hues in the near-darkness. “It’s a big surprise,” says Zuzana Musilova at the University of Basel in Switzerland. “They have more sensitive eyes and can see way better than humans in lower light.” Musilova and her colleagues collected DNA from 26 species of fish that live more than 200 metres below sea-level. Analysing this DNA, the team found that six species carried additional genes for rod opsin – the light-sensitive protein that enables the retina’s rod cells to detect light. Vertebrate animals use rod opsin to detect light in dim environments, but most species – including humans – only have one rod opsin gene. However, adult silver spiny fins (Diretmus argenteus) – a flat fish that lives at depths down to 2,000 meters— has 38 of them. The team translated these genes into proteins in a dish and shone lights of different wavelengths onto them, to see how they’d respond. They found that that these opsins detect a wide range of colours, and are especially sensitive to green and blue light. “We believe they can detect more shades of blue and green than us,” Musilova says. Musilova says having highly sensitive eyes may be useful for detecting the glowing bioluminescence emitted by many deep-sea creatures. These bioluminescent lights are mostly blue and green in colour. Being able to tell colours apart could help fish distinguish whether a flash comes a predator or prey, Musilova says.
5-9-19 Chimpanzees observed ganging up on a leopard and stealing its food
A group of chimpanzees stole a freshly killed animal from a leopard, then ate it. It is the first time the apes have been seen challenging such a large and dangerous predator. The finding could show how ancient apes and hominins first gained access to meat as a food source, and hints at the origins of cooperative hunting. Michio Nakamura of Kyoto University in Japan and his colleagues study a group of wild chimpanzees living in Mahale Mountains National Park in Tanzania. On the morning of 15 November 2016, Nakamura and a colleague were observing the chimps when they noticed a leopard sitting nearby. It soon moved off, perhaps because some of the chimps made intimidating “waa barks”. A little later the group’s alpha male, Primus, arrived and led some of the chimps to a nearby tree, in which a female named Christina was sitting. All of them looked at a patch of thick bush on the ground. Then Christina climbed down, went into the bush, and pulled out the body of an antelope called a blue duiker (Philantomba monticola). It was freshly dead, with wounds on its throat that were still oozing blood. Over the next five hours, the chimps took turns to eat the duiker, consuming its intestines, right hind leg and left forelimb. Throughout this period, various lines of evidence indicate that the leopard was either continually present or kept returning to the scene – perhaps trying to recover the duiker. Chimpanzees intermittently made waa barks again, and at one point the leopard was sighted by one of the observers. Nevertheless, the chimps made no attempt to flee. The chimps had the advantage of numbers, says Nakamura. Leopards sometimes hunt lone chimps or mothers with dependent young, but in this case “there were some ten chimpanzees, including one adult male, rushing to the scene,” he says. The incident illustrates the advantages chimps gain from living in cooperative social groups, he says, pointing to their ability to mount coordinated hunts for prey like colobus monkeys.
5-9-19 Penguin and seal dung nourishes organisms that are kilometres away
Penguin and seal poo can help plants that are kilometres away. Nitrogen from the dung spreads to areas 200 times larger than the animals’ colonies in Antarctica, nourishing the plants and other animals. Antarctic penguins and elephant seals play an important role in transporting nutrients from the ocean to land. They feed on small marine animals, and unabsorbed nutrients are expelled as faeces. Stef Bokhorst at Vrije Universiteit Amsterdam and his colleagues wanted to know how penguin and seal dung might affect the Antarctic land ecosystem. So the team collected moss and lichen, which are Antarctica’s primary vegetation, from 67 different sites across the Antarctic Peninsula. They also sampled water bears and springtails – tiny creatures that feed on the vegetation, as well as predatory mites that eat small bugs. Their analysis showed an elevated level of an isotope of nitrogen called nitrogen-15 in all organisms growing in areas that had penguin and seal colonies compared to those that grew in regions without any mammal colonies. The nitrogen-15 levels were so high that it could be from no other source but penguin and seal dung, Bokhorst says. Penguins and seals excrete large amounts of nitrogen-15 because of their protein-rich diet. The nitrogen evaporates from their faeces and is blown inland by ocean wind. This effect can extend over an area of 6.6 square kilometres at most and up to 240 times the size of a penguin or seal colony. The nitrogen enriches the soil and in turn increases the abundance of moss, lichen and other animals, as it is an important nutrient for organisms. As a result, in areas under the influence of marine mammal colonies, the team often observes 10 times more springtails in Antarctic moss communities than European grasslands, where the climate is milder, Bokhorst says.
5-8-19 Underwater tests reveal sharks may be smarter than you think
Sharks may be smarter than they seem. Recent experiments reveal they have a grasp of quantity and can learn cognitive skills from other sharks. SHARKS may be even more calculating than they seem. They can learn cognitive skills from other sharks and recent experiments reveal they have a grasp of quantity. Vera Schluessel at the University of Bonn in Germany and her colleagues tested how well 12 bamboo sharks could recognise different numbers of objects. Each shark was put in a training pool with pictures of two different groups of geometric shapes projected onto a wall. The team then cycled through at least 40 objects of different shapes and shades to ensure the sharks weren’t simply picking up on the darkness of the objects or the area of wall they covered. Around half the sharks learned to reliably press their nose against the image with the most objects, after which they were rewarded with food. These sharks only seemed capable of picking out the bigger group if it contained at least two more objects than the smaller one. This may be because the difference between six and seven fish or predators is unimportant in the wild, says Schluessel. The reason not all the sharks learned how to do the task could be because they, like all animals, have intellectual differences. Sharks join a growing number of animals that have been discovered to have similar skills at distinguishing quantities, including black bears, guppies and rhesus monkeys. In one experiment, dogs and wolves were able to reliably pick the larger of two groups. But dogs could only do so when one of the groups had substantially more objects. Some shark species are social learners and can perform a task in a tank more quickly if they watch another shark that has already been trained to do it.
5-8-19 Birds introduced to Hawaii have evolved rapidly in just decades
Non-native birds are replacing Hawaii’s endemic species, adapting to new environments at a blistering pace of evolution. In the Hawaiian Islands, most native fruit-eating birds have gone extinct and been replaced by introduced counterparts. On the island of O’ahu, seed dispersal through fruit consumption is now mostly carried out by non-native species. Jason Gleditsch, of the University of Illinois at Urbana-Champaign, and his colleagues have been studying how these changes have affected the island. They have found that, despite the loss of native fruit-eaters, O’ahu still has complex, functioning ecosystems – possibly thanks to rapid evolution of non-native birds to fill the niches vacated by the lost endemic species. To see whether the introduced birds have been evolving on O’ahu, Gleditsch and his colleague Jinelle Sperry compared four non-native songbird species on the island with museum specimens collected from their native range relatives. They measured the birds’ bills, tails, legs and wings – body parts that are all used for foraging.They discovered that, since living on the island, these birds have undergone substantial physical changes of up to 13 per cent in some measurements over a remarkably brief period. Compared to native range specimens, two species had significantly shorter legs, and most species had larger, thicker bills, shorter wings, and longer tails. The four species studied were introduced to O’ahu only 50 to 90 years ago. “Evolution is typically thought to occur over millennia,” says Gleditsch. “We’re talking about ten to twenty generations at most.” But statistical analysis suggests that the birds’ evolution is likely only partially shaped by adapting to life on the island. There’s evidence that “founder effects” may also have been at work – an evolutionary phenomenon in which the genetic mix of a small starting population can prompt a species to evolve changes that aren’t necessarily useful or adaptive. (Webmaster's comment: When an animal makes new children every year, and last years children are making more new children, evolution can be very rapid.)
5-8-19 Wasps are the first invertebrates seen to use a type of logic
Logical reasoning is complex behaviour, and has often been thought to be limited to animals that have complex nervous systems. But a new study shows that wasps can use a kind of logical deduction, the first such finding in invertebrates. The type of reasoning is called transitive inference and it’s something people do easily: if you know that A is bigger than B, and B is bigger than C, then you can reason that A is bigger than C. Elizabeth Tibbets at the University of Michigan and her team put 40 paper wasps (23 Polistes dominula and 17 Polistes metricus) individually into a shallow rectangular container that had one of 5 colours, labelled A to E, at each end. An electric shock was placed under the side of the container that was highest in the alphabet in each pair. The wasps were first trained on letters that were adjacent to each other – A/B, B/C, C/D, and D/E. After 10 trials, they were then tested on pairs B/D and A/E, meaning they would have to use logic to avoid getting a shock. Overall, 65 per cent of the wasps managed to correctly choose B over D, which is better than chance. They also chose A over E at around the same rate, but since A was always free of shocks and E always delivered them, that may be less significant, says Tibbets. Wasps may have evolved this ability because of their social structures. “They spend a huge amount of time fighting about dominant rank, and transitive inference is really important for figuring out dominance relationships,” says Tibbets. This type of study has been tried with honeybees, but they weren’t found to use the same deduction processes. Perhaps that’s because they don’t form these same dominance hierarchies, Tibbets says.
5-7-19 A belly full of wriggling worms makes wood beetles better recyclers
Common decomposers infested with benign nematodes eat more and so release more nutrients. Having hundreds of roundworms living inside your abdomen may seem like a bad thing. But for horned passalus beetles, hosting wriggly nematode larvae may benefit them and the eastern U.S. forests they live in. Beetles that harbor Chondronema passali larvae eat more rotting wood than beetles without the larvae, researchers report May 1 in Biology Letters. That increased decomposition could speed the cycling of forest nutrients, the authors suggest. Earlier research found that about 70 to 90 percent of Odontotaenius disjunctus, commonly called bess beetles or patent leather beetles, are inhabited by hundreds if not thousands of nematodes, but appear to suffer few ill effects. The larvae feed off the beetles’ haemolymph, the insect version of blood, and in doing so suck up some of the beetles’ available energy, an effect that’s noticeable only when the beetles are under short-term stress. That increased need for energy could be what drives infected beetles to chomp more wood, says Andy Davis, an ecologist at the University of Georgia in Athens. It’s also possible that beetles with larger appetites have more opportunities to become infected since they eat more wood, he says. Davis and undergraduate student Cody Prouty captured 113 beetles from the woods near campus and isolated each one in a container with a chunk of wood. “On a quiet day, you could go in the lab and hear them chewing,” Prouty says.
5-7-19 Trophy hunting: Gove 'cautious' over ban on imports
The UK will not be banning imports from trophy hunting yet, Michael Gove has told BBC Radio 5 Live. The Environment Secretary said it was a "delicate political balancing act". He said he had been advised by wildlife charities to "be cautious" in following other countries in outlawing imports from the controversial sport. Trophy hunting is the shooting of carefully selected animals, including some endangered species, under strict government controls. Mr Gove was interviewed by former England cricketer Kevin Pietersen as part of a new BBC Radio 5 Live podcast, Beast of Man, which looks into how the South African rhino can be saved from extinction. Clients, mainly from Europe or the US, often pay thousands of pounds to take part in a hunt, and keep a "trophy" - usually the head or skin, or another body part. It's a big business in some African countries. Critics describe it as a blood sport, but proponents say it helps raise vital money for conservation, especially for endangered species. (Webmaster's comment: But mostly it reinforces the desire to kill something, anything, in the human male!)
5-7-19 British bluebells 'have advantage over Spanish bluebells'
Fears that the British bluebell could go extinct are unfounded, say scientists. The introduced Spanish variety has lower fertility and is unlikely to wipe out the native plant, according to genetic tests. The Spanish bluebell's escape into the wild has raised concerns that the two plants could mix, leading to the loss of one of the spectacles of spring. The violet-blue flowers appear in April and May, carpeting the woodland floor. It turns out that the British bluebell has a genetic advantage. "The greater fertility of the native British bluebell coupled with the huge numbers of individuals that exist in the wild means that it's got considerable resilience against any threat from these introduced plants," said Prof Pete Hollingsworth, director of science at the Royal Botanic Garden Edinburgh (RBGE). The British bluebell is one of the nation's best-loved plants, with 50% of the world's population found in the UK. The native bluebell, Hyacinthoides non-scripta, also goes by the name common bluebell, wood bell, fairy flower and wild hyacinth. Millions of bulbs can be found in just one ancient woodland, giving rise to carpets of flowers in April and May. The Spanish bluebell, Hyacinthoides hispanica, was introduced into the UK by the Victorians as a garden plant and can be found today alongside the native bluebell in woodlands as well as on road verges and in gardens.
5-5-19 Monkeys seem to prefer each other's company after a scary experience
After a frightening experience, some people like company – and that might go for monkeys too. When a hurricane devastated a small island, its resident rhesus macaques became more sociable, spending more time close to each other in the following months. The uninhabited island of Cayo Santiago, off the coast of Puerto Rico, is home to about 1500 macaques, descendants of animals taken there 80 years ago for medical research. Ever since, they have been given food but otherwise left to live naturally. The site, called Monkey Island, has become a useful way to study primate behaviour and genetics. Two years ago, hurricane Maria hit the Carribbean, killing thousands of people on Puerto Rico and leaving many without electricity and water. On Monkey Island, much of the vegetation was destroyed, with trees uprooted or stripped of their leaves. It must have been terrifying for the animals, says Sam Larson of the University of Pennsylvania. “If I woke up and all those trees had gone I would feel like something was wrong. And the hurricane itself has got to be the scariest thing. I would be clinging on to trees for dear life.” A tenth of the monkeys died in the storm, their feeding stations and water sources were disrupted and their social lives changed too. Before the hurricane, the monkeys were fairly stand-offish with unrelated individuals, and often attacked unfamiliar monkeys who got too close. The year after, they were more often seen alongside other animals, even unrelated ones, although they didn’t groom each other more. In one group, monkeys were observed with another within a two-metre radius up to 10 times as often as before the hurricane. Larson says one possibility is the company helped the animals feel less stressed by the radical changes to their environment.
5-4-19 Meet the scientists studying seal poo
The British Antarctic Survey are monitoring the droppings of some of the higher predators on the island of South Georgia in the Antarctic.They say it helps them keep track of what's happening in the environment.
5-3-19 Spy whale
Norwegian fishermen found a tame beluga whale last week that may have been trained by the Russian navy to be used in special operations. The whale, which approaches people to be petted and knows how to fetch, was wearing a harness that read “Equipment of St. Petersburg” in English and had a mount for a camera, although no camera was attached. “A Russian researcher I have spoken to says she knows that the Russian defense has such whales in captivity for military training,” marine biologist Audun Rikardsen told the Norwegian daily Aftenposten. In the mid-1990s, a tame beluga—a species native to the Arctic—was found swimming in the Black Sea, where Russia has a naval base. Its teeth had been filed down, possibly so it could hold a magnetic mine in its mouth.
5-3-19 Biodiversity heroes: The teenagers saving Madagascar's wildlife
The island nation of Madagascar has a dubious accolade: it is the world-leader in deforestation. Now, some of the island's teenagers have started a farming revolution - working to stop food production from destroying the island's rich rainforest. The bridge across the river to Mangabe has collapsed. Probably many years ago. Just a few wooden stumps now protrude from the murky water separating densely forested riverbanks. The only way across is on an unnervingly wobbly canoe. We crouch low - backpacks at our feet - gripping the sides of that canoe as it is expertly steered across the water. We are less than 100 miles from the capital of Madagascar, Antananarivo, but this is a stark reminder of just how remote the communities of this protected area are. When we have crossed the river, it is still a two-hour walk to Mangabe village. We're going there to meet a group of Malagasy teenagers - young famers who are leading a small but vital revolution - transforming how people farm in order to save their forest. Almost 9,000km away in Paris, at a glossy, international gathering, scientists and politicians are finalising an assessment on humanity's relationship with nature. With its somewhat ungainly title, the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) will publish a seminal upsum of the ecological emergency our planet is facing; humanity's impact on the natural world. There is little doubt that, worldwide, humanity struggles to coexist with other species that inhabit the planet - even some that we are keenly aware that we need. Biodiversity encompasses pollinating insects we rely on for food, trees and plants that provide clean air and water and the network of life underfoot that keeps soil fertile and productive. It is the network of life - we depend on it. The global report due on 6 May has the lofty goal of setting out a path to a more sustainable future. But here in Mangabe, communities live alongside one of the richest, most diverse rainforests in the world. They make their livelihoods entirely through farming; here the link between people and the forest is palpable and inextricable.
5-2-19 Pandas’ share of protein calories from bamboo rivals wolves’ from meat
Skewed digestive powers give the plant eaters the ability to extract the key nutrient. Giant pandas eat bamboo like a wolf in vegan clothing. In the wild, pandas devour massive amounts of bamboo and digest it so efficiently that protein from the plants probably supplies at least half of the animals’ calories, a study finds. That’s about on par with measurements of how many calories from protein make up the carnivorous diets of wolves and feral cats, conservation biologist Fuwen Wei of the Chinese Academy of Sciences in Beijing and colleagues report May 2 in Current Biology. Giant pandas, which evolved from omnivores and carnivores, still show some strong signs of ancestral meat eating. Biologists knew that a panda’s gut works more like a carnivore’s than an herbivore’s, and has microbial residents similar to a carnivore’s. So Wei and colleagues wanted to see how that carnivore-like gut handled a bamboo diet. Lurking in bamboo stands in China’s Qingling Mountains, the researchers gathered wild panda poop for analysis. Comparing the nutrients excreted by pandas with nutrients in bamboo plants gave the researchers a sense of how much protein, carbohydrates and fat were being absorbed by the animals. The fieldwork focused on China’s northernmost population of wild pandas, which dine mainly on two bamboo species found in the Foping Nature Reserve. Pandas are not small animals, yet “they do not make a lot of noise in bamboo,” Wei says. But some of the pandas had been fitted with collars carrying GPS trackers, which helped the researchers find and stay within about 20 meters of the animals to quickly scoop up some of the roughly 120 droppings left by each panda in a day of grazing.
5-2-19 Pollution-proof fish borrow genes from relatives to survive toxins
In comic books, falling into a vat of toxic chemicals can give you super powers. The same is sort of true for one species of fish – with help from a superhero relative. The 15-centimetre-long Gulf killifish (Fundulus grandis) lives in estuaries around the Gulf of Mexico, some of which are heavily polluted. They survive levels of toxic halogenated and polycyclic aromatic hydrocarbons (HAHs and PAHs) that cause lethal deformities in other animals. The killifish in these regions have evolved resistance in less than 60 years. To discover how they did it, Elias Oziolor of Baylor University in Texas and colleagues compared the genomes of the toughest fish with those from less polluted areas. They found that many of the genetic variants conferring resistance come from a related species, the Atlantic killifish or mummichog (Fundus heteroclitus) – an astonishingly tough fish that has evolved resistance to many pollutants. That’s surprising because the mummichog normally lives along the Atlantic coast, and the nearest population to the Gulf of Mexico is 2500 kilometres away in Florida. The team think a few mummichog were carried to the Houston Ship Channel, possibly in the ballast water of ships, where they mated with Gulf killifish. It is now clear that evolution can happen extremely rapidly. However, it requires lots of genetic variation for natural selection to act on. It appears the Gulf killifish did not harbour enough variation among themselves but were saved by genes introduced by hybridisation. Because many threatened species have lost genetic diversity just when they need it to adapt to a changing world, some biologists have suggested that we should deliberately hybridise species to provide more diversity for evolution to act on.
5-2-19 Older bees pass on immunity-boosting molecules to other bees in jelly
Bee colonies are even more of a superorganism than we thought. When disease strikes, bees can add immunity-providing molecules to the jellies they feed to larvae, to give the hive a kind of collective immune system. A decade ago, Eyal Maori at Cambridge University and colleagues tested a new way of treating diseases in bees. The treatment was based on a technique RNA interference, which involves feeding the bees double-stranded RNA molecules that shut down specific genes. Many insects naturally produce these double-stranded RNA molecules as an immune response to infections by viruses, bacteria or fungi. The treatment worked, but strangely kept on working for months, even after the bees fed the RNAs were dead, suggesting the protection was somehow being passed on to young bees. Now investigating this further, Maori and his team found that bees pass RNAs on to other bees by adding them to the worker and royal jellies that they secrete to feed larvae. What’s more, bees produce special proteins that bind to RNAs to protect the molecules and prevent them from breaking down. This is the first time that individuals of the same species have been shown to exchange RNA in this way, says Maori. When the team sequenced the natural RNAs in the jellies, they found RNAs corresponding to ten viruses, suggesting that bees start making and sharing disease-targeting RNAs when infections strike. Bees may use RNAs for more than defence. The team suspect that they are the key ingredient in the royal jelly that makes larvae turn into queens rather than workers. Bees may also use RNAs to prepare future generations for the specific environment they will face. “This could be a form of social epigenetics,” Maori says.
5-1-19 We still don't know how some animals find their way on huge migrations
From ants to bees to birds, animals cross vast and often unknown territories to reach food and breeding grounds. A new book looks at their extraordinary wayfinding skills. THERE seems to be no limit to the resourcefulness with which insects, birds, fish and mammals navigate their way through the world. Consider the desert ant. After meandering hundreds of metres from its nest, the ant manages to scuttle home in a straight line across unfamiliar ground. Honeybees use an internal clock and sensitivity to polarised light to remember the location of food, communicating it to their hive through their famous waggle dance. And there is the Arctic tern, taking a round trip from the north Atlantic to Antarctica of more than 70,000 kilometres. David Barrie’s Incredible Journeys is brimful of such wayfinding wonders. But it is as valuable for what it reveals about our ignorance. No one knows how those terns stay the course across vast expanses of open ocean, nor how juvenile European cuckoos find their way to their wintering grounds in Africa for the first time without a guiding parent. Pigeons are known to have a keen sense of smell, but, despite decades of research, we can’t agree if they use it to navigate. The consensus is that many animals can sense Earth’s magnetic field, but how they use it remains unclear. “There are three radically different theories, any or all of which may prove to be correct,” writes Barrie, adding that “some entirely different mechanism… may be at work”. Many biologists have spent their lives wrestling with these mysteries, and their obsessive ponderings and ingenious experiments are as fascinating as the behaviours they study. Take Rüdiger Wehner, one of the greatest authorities on the navigational abilities of ants. He made his breakthrough discovery – that they orientate using an inbuilt “sun compass”– by painting over parts of their tiny compound eyes and watching their response.
5-1-19 Hippos poop a huge amount of silicon every day – and it’s a good thing
By eating huge amounts of grass and then defecating in water, hippos are acting like living silicon pumps – and the health of their habitat may depend on it. Every evening, hippos eat around 40 kilograms of grass and other plants rich in silicon dioxide – also known as silica – only to spend the following day lazing around in the water where they digest and excrete it. While researchers have previously studied the role hippos play in moving nitrogen, carbon and phosphorus around their ecosystem, it has been unclear whether they also influence silicon in their habitat. To find out, Jonas Schoelynck at the University of Antwerp, Belgium, and his colleagues studied the silicon levels in a hippo-dominated ecosystem in south-western Kenya. In one 250-metre stretch of the river Mara, they spotted up to 80 hippos. Analysing dissolved and particulate silicon in the river revealed that the hippos transported a total 0.4 tonnes of silicon a day – that’s 76 per cent of the total movement of silicon throughout the ecosystem. “Hippos act as a kind of conveyor belt, transporting silica from land to water,” says Schoelynck. This silicon pump in hippo form is vital to the ecosystem, because single-celled algae in the water need this element, and algae provide food for the other plants and animals in the waterways, Schoelynck says. But hippos have been killed or driven out from most of the rivers that lead into one of Africa’s great lakes, Lake Victoria. If populations shrink further, the amount of silicon pumped into waterways will diminish, and the important plants and fish there could be in jeopardy, says the team.
5-1-19 Hippo poop cycles silicon through the East African environment
The animals play an outsized role in pumping a nutrient crucial to the food web into waterways. Hippos keep the nutrient silicon on the move through the East African environment. Each day, the giant grazers transport nearly half a metric ton of silicon, an important nutrient for both plants and animals, from land to water, scientists report online May 1 in Science Advances. The hippos forage for silicon-bearing grass on land and then excrete it into the waters where they lounge. A team led by biologist Jonas Schoelynck of the University of Antwerp in Belgium tracked silicon moving through Kenya’s Mara River, a hippo hangout, by analyzing ratios of two silicon isotopes — versions of the element with different masses — in grasses, hippo feces, soil and waters. Those ratios are modified by different biological and chemical processes, so can act as fingerprints for the different sources of silicon. The team found that hippos play an outsized role in cycling silicon through the local ecosystem. Hippos grazing on grasses in the savanna can consume about 800 kilograms of silicon daily through the plants. As a hippo lingers in the water, it can excrete about half of the silicon it consumed. All told, the animals “pumped” 0.4 metric tons of silicon from the grasslands into the Mara River daily, increasing the total amount of silicon measured in the water by more than 76 percent, the team estimates. Having more silicon available is particularly important for tiny floating alga called diatoms to build their silica shells (SN: 7/17/04, p. 42), the researchers note. But hippos are threatened by hunting and habitat loss: Populations decreased by up to 20 percent from 1996 to 2004. If the animals were to vanish from the Mara River, diatom growth in the water could decrease dramatically. Because the single-cell diatoms are at the base of the food web, that, in turn, could cause a cascade of food shortages across the ecosystem.
5-1-19 Narwhals are thriving despite extremely low genetic diversity
The narwhal gene pool is not very diverse. That is normally a problem for animal populations, making them less able to adapt to changing circumstances. But narwhals are doing pretty well – which suggests genetic diversity might not be as vital as we think. Narwhals are toothed whales that live in the Arctic, and are famous for having an enlarged tusk that protrudes from their upper jaw. Michael Westbury of the Natural History Museum of Denmark and his colleagues sequenced the genome of a narwhal from west Greenland. The genome of a single individual can tell biologists a lot about the genetic diversity of the species, not only now but deep in the past. For each section of the genome, every individual has two copies: one from their mother and one from their father. By comparing how similar these sequences are, and how areas of high and low similarity are spread throughout the genome, geneticists can piece together how closely related the animal’s parents were, and make inferences about ancestral populations. The analysis found much lower levels of diversity throughout the narwhal genome compared with other Arctic marine mammals, like the beluga whale, the bowhead whale and the walrus. Low diversity is often the result of inbreeding, or a small population size. But neither of these explanations fits with the narwhal data. The global population is estimated at 170,000 – enough to change their official conservation status from “near threatened” to “least concern” recently. Their genetics suggest the narwhal population has grown rapidly since the start of the last glacial period around 115,000 years ago, but before this had been slowly declining for about a million years. This gradual decline might explain why the lack of diversity does not seem to be a problem. While a rapid population crash can mean important genetic variations are lost, the narwhals’ slow decline could have enabled them to preserve diversity where it matters.
5-1-19 Pandas gobble as much protein as polar bears despite being vegetarian
Pandas’ obsession with bamboo doesn’t appear to make sense. None of their bear relatives are vegetarian, and their digestive system still looks like that of a meat eater. However, a study has found that pandas eat the same amount of protein as that of carnivores, offering a possible explanation for their seemingly mismatched diet and digestive system. Previous research has found that although pandas evolved teeth and jaw bones for chewing bamboo, these vegetarian bears have a digestive tract that resembles that of a carnivore. Fuwen Wei at the Chinese Academy of Sciences in Beijing and his colleagues studied pandas living in Foping National Nature Reserve in north-west China. Over the course of 15 years, the team followed several pandas closely to collect their leftover food. After analysing the food’s protein levels, the team found protein contributed to about 50 per cent of their diet, which is comparable to that of carnivores, such as polar bears. Other herbivorous mammals, like horses, usually have a diet composed of only 20 per cent of protein. “We were very surprised,” says Wei. Pandas’ intake of carbohydrates and fats was also similar to meat eaters. Although pandas exclusively eat bamboo, they are very picky about which part of the plant they eat, says Wei. Pandas forage for bamboo shoots, which have the highest protein content of all parts of the plant. In summer, when the shoots in lower altitude areas mature and become fibrous, pandas migrate into the mountains to look for late sprouts. During autumn and winter, when shoots are not available, they mostly eat bamboo leaves and ditch the stems, which are hard and low in protein. This may explain why pandas have retained a carnivorous digestive system, says Wei.