11-25-21 Feeding pet dogs just once a day might keep them healthier as they age
Dogs fed once a day are less likely to be diagnosed with age-related conditions than dogs fed more often, according to an analysis of surveys completed by 24,000 owners of pet dogs. For now, dog owners should stick with their current regime, says Matt Kaeberlein at the University of Washington in Seattle. “Based on this study, we are not recommending that people make a change in the way they are feeding their dogs.” In 2019, Kaeberlein helped establish the Dog Aging Project to study the genetic and environmental causes of ageing in dogs and other animals, including people. Any dog owner in the US can take part by filling in a survey once a year. There is some evidence that intermittent fasting can slow ageing in some animals, such as mice. Kaeberlein analysed the project data to see if dogs fed once a day were more or less likely to be diagnosed with various categories of age-related conditions, from cancers to the canine equivalent of dementia, than those fed more often. In most cases, dogs fed once per day were significantly less likely to have had such a diagnosis. “In my view, it’s pretty compelling correlative evidence,” says Kaeberlein. However, the study hasn’t established causation, he says. The total amount that a dog eats, rather than how often it eats, might explain the correlation. Dogs fed twice a day or more might be more likely to be obese, for instance. The project team plans to ask owners how much their dogs eat and whether they are obese. But measuring caloric intake accurately is hard to do in surveys, says Kaeberlein. Ideally, the team would like to carry out a trial involving switching some dogs to once-a-day-feeding to see if it affects their health. “The strength of the study is that numbers are large and the statistical methods are sound,” says Alex German at the University of Liverpool in the UK. But it also has many weaknesses, he says, and he “strongly agrees that people shouldn’t change the way they feed their dogs until further studies are done.”
11-25-21 Wild Wild Life newsletter: How you can 'do your bit' for wildlife
Greenwashing is rife and full of ineffectual suggestions for saving the planet. Here are four lifestyle changes that actually do make a difference for biodiversity. Hello, and welcome to November’s Wild Wild Life, the monthly newsletter that celebrates the biodiversity of our planet’s animals plants and other organisms. To receive this free, monthly newsletter in your inbox, sign up here. I’ve been breaking in a new pair of walking boots on woodland walks, spotting as many fungi as I can. I can’t pretend to be anywhere near an expert – the UK is home to more than 15,000 species of fungi. That number isn’t quite as daunting as it sounds, though, because many of these species are microscopic and not mushroom-forming. I’ve had some successes in identifying the most common species, but I still marvel at anyone who is confident enough to eat those that they identify as edible. This month, in the aftermath of COP26, I’m looking at actions we can meaningfully take to help wildlife and lessen the biodiversity crisis. Plus, why it pays to have really red feathers if you’re a waxbill, and a newly recognised species of octopus. The COP26 summit in Glasgow, UK, this month was the biggest opportunity to tackle climate change since the Paris Agreement, back in 2015. Amid all the breaking news, big pledges and grand announcements, something kept niggling at me. I couldn’t turn on the TV without an advert telling me I could “do my bit” by recycling a plastic bag or eating a veggie burger. My problem with such messages is that they are nowhere near enough to be “my bit” – anything that’s promoting easy swaps or simple lifestyle changes sounds great but is unlikely to have any impact on the problem. Greenwashing has become a familiar concept now, and I’ve written before about more meaningful action that people can take both to tackle climate change and cope with eco-anxiety. But what about the other great planetary crisis besides climate change: the biodiversity crisis? Humans and our domesticated animals now make up more than 90 per cent of the mammalian mass living on our planet. The things we do are threatening around 1 in 8 species with extinction, and just 3 per cent of Earth’s land is classed as ecologically intact.
11-24-21 Albatrosses divorce more often when ocean waters warm
The typically monogamous birds seek new partners when conditions are harsher than usual. When it comes to fidelity, birds fit the bill: Over 90 percent of all bird species are monogamous and — mostly — stay faithful, perhaps none more famously than the majestic albatross. Albatross couples rarely separate, sticking with the same breeding partner year after year. But when ocean waters are warmer than average, more of the birds split up, a new study finds. In years when the water was warmer than usual, the divorce rate — typically less than 4 percent on average — rose to nearly 8 percent among albatrosses in part of the Falkland Islands, researchers report November 24 in Proceedings of the Royal Society B. It’s the first evidence that the environment, not just breeding failure, affects divorce in wild birds. In fact, the team found that during warmer years, even some females that had bred successfully ditched their partners. The result suggests that as the climate changes as a result of human activity, higher instances of divorce in albatrosses and perhaps other socially monogamous animals may be “an overlooked consequence,” the researchers write. Albatrosses can live for decades, sometimes spending years out on the ocean searching for food and returning to land only to breed. Pairs that stay together have the benefits of familiarity and improved coordination, which help when raising young. This stability is particularly important in dynamic, marine environments, says Francesco Ventura, a conservation biologist at the University of Lisbon in Portugal. But if breeding doesn’t work out, many birds — mostly females — leave their partner and try to find better luck elsewhere (SN: 3/7/98). Breeding is more likely to fail in years with more difficult conditions, with knock-on effects on divorce rates the following years. Ventura wanted to find out whether the environment also has a direct impact: changing the rate of divorce regardless of whether the breeding had gone well.
11-24-21 Hybrid salmon found in Canada may be a result of climate change
Salmon found near the mouth of the Cowichan river on Vancouver Island are a hybrid species of coho and Chinook, which may have arisen as the timing and location of their spawning grounds overlapped. Hybrid salmon have emerged near Vancouver Island in Canada, possibly due to environmental changes in the waterways where they hatched. Andres Araujo at Fisheries and Oceans Canada in Nanaimo and his colleagues analysed the genes of salmon surveyed mostly within the Strait of Georgia, which separates Vancouver Island from the mainland, between 2013 and 2019. They found that samples from what they assumed to be young Chinook salmon (Oncorhynchus tshawytscha) had unusual genetic markers. More sampling and genetic analysis revealed that these fish were hybrids, crossed with coho salmon (Oncorhynchus kisutch), another species found in the region. Many of the hybrids look like a mix of the two species, says Araujo. Some have grey-lined gums, intermediate between the Chinook’s black gums and pale coho gums, for example. Hybrid salmon have been documented before, but very rarely. In the latest study, the team found a persistent, low-level presence of hybrids, most of which were found near the mouth of the Cowichan river, an important spawning ground for the two species. The team says nearly 5 per cent of the fish sampled that are thought to have originated in the Cowichan are hybrids. Araujo and his colleagues think these hybrids could be a result of the impact of climate change on the Cowichan. In recent years, dry conditions have lowered the river’s water level, delaying the start of the Chinook salmon’s late summer spawning. This increases the chance that the coho – which arrive and spawn in the autumn – will overlap with the Chinook spawning, possibly resulting in interbreeding.
11-22-21 Octopus-inspired camouflage fabric can change colour to blend in
Many camouflage materials are limited by the need for power or external sensors as they effectively record video of what is behind an object to be hidden and display it on the front. Instead, a new material inspired by octopuses and squid shines an infrared torch on an object to match its surroundings. Xuesong Jiang at Shanghai Jiao Tong University in China and his colleagues have created the material from two layers, each of which has a different thermal expansion rate. One layer is infused with pigments of mixed colours and the other is made to be the same colour as the background. When the material is cool, the layers have different tensions, which causes tiny wrinkles and creases to form on the surface. Light shone onto the surface warms up the layers, causing them to expand at different rates and making the two materials smooth again. Creating and eradicating these wrinkles allows the colour of any reflected light to be controlled. In the wrinkled state, a mixed spectrum of bright colour is reflected, but when the material smoothes out, the reflected colour matches the background, and whatever is clad in the material becomes camouflaged. Because the system doesn’t use sensors or power, researchers believe it could create inexpensive adaptive camouflage uniforms. The US Army has previously made a call for proposals for wearable camouflage with chameleon-like abilities.
11-18-21 Red crabs swarm across roads and bridges in Australia
Tens of millions of red crabs have covered roads and bridges on Christmas Island as they undertake their annual migration. The crabs are travelling from the forest to the coast to spawn, the migration beginning shortly after the first rainfall of the wet season.
11-18-21 This eco-friendly glitter gets its color from plants, not plastic
Minuscule arrangements in cellulose reflect light in specific ways to give rise to vibrant hues. All that glitters is not green. Glitter and shimmery pigments are often made using toxic compounds or pollutive microplastics (SN: 4/15/19). That makes the sparkly stuff, notoriously difficult to clean up in the house, a scourge on the environment too. A new, nontoxic, biodegradable alternative could change that. In the material, cellulose — the main building block of plant cell walls — creates nanoscale patterns that give rise to vibrant structural colors (SN: 9/28/21). Such a material could be used to make eco-friendly glitter and shiny pigments for paints, cosmetics or packaging, researchers report November 11 in Nature Materials. The inspiration to harness cellulose came from the African plant Pollia condensata, which produces bright, iridescent blue fruits called marble berries. Tiny patterns of cellulose fibers in the berries’ cell walls reflect specific wavelengths of light to create the signature hue. “I thought, if the plants can make it, we should be able to make it,” says chemist Silvia Vignolini of the University of Cambridge. Vignolini and colleagues whipped up a watery mixture containing cellulose fibers and poured it onto plastic. As the liquid dried into a film, the rodlike fibers settled into helical structures resembling spiral staircases. Tweaking factors such as the steepness of those staircases changed which wavelengths of light the cellulose arrangements reflected, and therefore the color of the film. That allowed the researchers, like fairy-tale characters spinning straw into gold, to transform their clear, plant-based slurry into meter-long shimmery ribbons in a rainbow of colors. These swaths could then be peeled off their plastic platform and ground up to make glitter.
11-17-21 An inside look at oysters – and how to enjoy them safely
I LOVE raw oysters, so hoped to write a column saying there is no need to worry about food poisoning. When I looked into it, though, I found cause for concern. But there are safe ways to enjoy delicious oysters. Folklore has it that oysters can be eaten in any month with an “r” in it – in other words, avoiding the summer months, when they spawn. This discernment may date back to ancient times. By measuring parasitic snails in oyster shells, a study of a 4300-year-old human habitation in Georgia, US, found that ancient people mostly harvested oysters in the autumn, winter and spring. During the spawning season, oysters convert their resources into sperm or eggs, which renders them less palatable. People may also have avoided taking oysters in summer to allow populations to recover. Nowadays, farmed oysters are available and good to eat all year round and are among the most sustainable seafoods. Since the 1980s, many farmed oysters have been triploid: they have three sets of chromosomes and are therefore infertile. These oysters grow faster than natural oysters and remain firm and plump in the summer. As filter-feeders, oysters can pick up pathogens lurking in the water. To reduce this risk, they are usually kept in clean water for 42 hours after harvesting in the UK, a process called depuration. Sadly, this isn’t completely effective – particularly with respect to norovirus, one of the most common causes of gastroenteritis. A 2017 report found that between 100 and 1000 copies of the norovirus genome may remain in each gram of oyster tissue after depuration. Just 10 copies are thought to constitute an infectious dose. In the UK, about 13,000 people a year experience illness after eating seafood, usually raw oysters. Given that more than 13 million oyster meals are served each year, you might consider this a low risk. But recent headlines about raw sewage discharged around British coasts may make you think twice.
11-17-21 Why haven’t cats evolved since domestication, unlike other animals?
Cats were domesticated in ancient Egypt, yet unlike other domesticated animals, don’t seem to have evolved significantly since. Why? I have come to the conclusion that humans are at the whim of three things in life: the weather, hormones and cats. Ask any cat owner and you will discover that they have to do exactly as the animal bids, whether that means sitting uncomfortably so as not to disturb the cat sleeping on their knee, or holding open a door while it twitches its “tail of indecision” before running the other way. I therefore suggest that humans have subtly evolved to meet the needs of cats rather than the other way round. It could be argued that the domesticated European house cat has reached the top of the evolutionary ladder, with all the benefits of a 21st-century Western lifestyle and none of the drawbacks. It is worth thinking about this next time Tiddles jumps into your warm spot as you head off to work on a winter morning! When travelling in Egypt, visiting tombs from pharaonic times and looking at 4000-year-old frescos and statues featuring cats, one gets the impression that they were essential to the afterlife of kings, nobles, craftsmen and scribes. There are so many depictions of them throughout that period. There are the ferocious tomcats cutting off the head of a serpent demon, cats under the chairs of noble people, statues of cat-like goddesses and many cat mummies. These cats resemble present-day barn, village and house cats. Does this mean that cats were domesticated in Egypt but haven’t changed since? As is true for the history of all domestic animals, the reality is much more complex. First of all, cats were probably domesticated in the Middle East at the dawn of agriculture thousands of years before they were introduced to Egyptian households. In the Middle East, the local wildcats must have been attracted by the rodents prowling around granaries in the settlements of early farmers. A special human-cat relationship was established that mutually benefited both partners: the cats must have been happy to feast on these rodents, while the farmers must have been happy to get rid of the pests.
11-17-21 AI predicts which mammals are most likely to spread covid-19
Water buffalo, Sunda pangolins and mink are among the 540 mammals predicted to be likely to spread the coronavirus based on their biology and where they live. An AI tool has predicted 540 mammalian species that are most likely to spread covid-19 using information about where they live and aspects of their biology. According to the model, mink, Sunda pangolins and bats are among the top 10 per cent of species most likely to spread covid-19, which matches results from lab experiments. The SARS-CoV-2 coronavirus, which causes covid-19, invades human and animal cells by engaging the ACE2 protein on host cells with its spike protein. This step is required to infect an animal and be transmitted to other hosts. Distinct species have different versions of the protein, so understanding how well their ACE2 protein binds to the coronavirus spike protein can help scientists predict which animals are most likely to spread covid-19. But the amino acid sequences that make up the ACE2 protein are available for only around 300 species. Barbara Han at the Cary Institute of Ecosystem Studies in New York and her colleagues built a machine learning tool to predict whether the ACE2 protein from 5400 mammalian species can bind strongly enough to the spike protein from the original coronavirus variant to spread the virus, even without knowing their ACE2 amino acid sequences. The species predicted to be able to harbour the virus include white-tailed deer, which were recently found to have very high rates of infection in North America. Striped skunk and 76 rodent species including rats and deer mice were also deemed likely to spread the coronavirus, along with some farmed species such as water buffalo. To create the model, the team first estimated how strongly the spike protein binds to the ACE2 protein from 142 mammalian species for which the ACE2 sequences are known, and whether or not these species are likely to spread the coronavirus based on this binding strength.
11-17-21 Pale barn owls in UK and Ireland hint at ancient land bridge
The barn owls of northern Europe are typically dark-feathered, making the pale-feathered barn owls of the UK and Ireland an anomaly - now a study suggests they arrived via an ancient land bridge connecting the area to Iberia. Barn owls are one of the most widely distributed birds, being found on six continents. In Europe, they follow a general pattern: southern areas host pale owls and darker birds dominate in the north. But barn owls in the UK and Ireland are consistently a stark white, and a new analysis explains why. Ana Paula Machado studied the owls (Tyto alba) while at the University of Lausanne in Switzerland. She and her colleagues analysed DNA from 147 barn owls across six European populations. They targeted a gene called MC1R, which is known to influence feather pigmentation in barn owls, along with 22 other genes the owls carry that have been linked to feather colour. In particular, they were looking for evidence that owls from Ireland and the UK had dark-feathered ancestors and then underwent strong selection for pale feathers, as an adaptation to local conditions. They didn’t find any. “We didn’t see that one coming,” says Machado, so they began looking for an alternative explanation. She and her colleagues used data on the habitats that barn owls occupy today to predict how they would have been distributed across Europe under ancient climatic conditions. This revealed a now-submerged land corridor of suitable owl habitat along the Bay of Biscay, bridging Iberia and the Ireland-UK region some 20,000 years ago. This suggests owls in the UK and Ireland had pale-feathered ancestors from southern Europe. The genetic data corroborates this, showing that owls from the region have close relations with those from Portugal. The Iberian route is a surprise. Most animals that recolonised the UK and Ireland after the Pleistocene ice sheets retreated around 18,000 years ago are thought to have entered via Doggerland, a boggy land bridge that existed at the time and connected Belgium with southern England.
11-13-21 Climate change may be shrinking tropical birds
Even a subtle decrease in size could help animals stay cooler, researchers suspec. In a remote corner of Brazil’s Amazon rainforest, researchers have spent decades catching and measuring birds in a large swath of forest unmarred by roads or deforestation. An exemplar of the Amazon’s dazzling diversity, the experimental plot was to act as a baseline that would reveal how habitat fragmentation, from logging or roads, can hollow out rainforests’ wild menagerie. But in this pristine pocket of wilderness, a more subtle shift is happening: The birds are shrinking. Over 40 years, dozens of Amazonian bird species have declined in mass. Many species have lost nearly 2 percent of their average body weight each decade, researchers report November 12 in Science Advances. What’s more, some species have grown longer wings. The changes coincide with a hotter, more variable climate, which could put a premium on leaner, more efficient bodies that help birds stay cool, the researchers say. “Climate change isn’t something of the future. It’s happening now and has been happening and has effects we haven’t thought of,” says Ben Winger, an ornithologist at the University of Michigan in Ann Arbor who wasn’t involved in the research but has documented similar shrinkage in migratory birds. Seeing the same patterns in so many bird species across widely different contexts “speaks to a more universal phenomenon,” he says. Biologists have long linked body size and temperature. In colder climates, it pays to be big because having a smaller surface area relative to one’s volume reduces heat loss through the skin and keeps the body warmer. As the climate warms, “you’d expect shrinking body sizes to help organisms off-load heat better,” says Vitek Jirinec, an ecologist at the Integral Ecology Research Center in Blue Lake, Calif.
11-12-21 Birds in the Amazon are adapting to climate change by getting smaller
An analysis of 77 tropical bird species in the Amazon shows that all of them have shrunk and a third developed longer wings over the past 40 years. Tropical birds deep in Brazil’s Amazon rainforest are shrinking and developing longer wings as they adapt to climate change. Researchers studied data for 77 tropical bird species over the past 40 years and found that all of them had lost body mass, with some species losing nearly 2 per cent of their weight per decade. A third of the species studied also developed longer wings. A landmark 2019 study of birds that had crashed into buildings in Chicago, Illinois, found that they had lost mass and gained wingspan over a 40-year period, but those species were migratory. To see whether seasonal migration, the birds gradually shifting latitude or the direct effects of human activity had been driving the change, researchers examined the records of 15,000 non-migratory birds inhabiting a pristine tract of rainforest a few hours drive from the city of Manaus in north-west Brazil. “We see these pretty remarkable changes in their bodies that are consistent with what we would expect under climate change,” says Vitek Jirinec at the Integral Ecology Research Center in California, who led the study. The mean temperature of the birds’ habitat today is 1°C warmer in the wet season and 1.65°C warmer in the dry season compared with 1966. Weather patterns are also more extreme, with 13 per cent more rain falling in the wet season and 15 per cent less in the dry season. The birds lost mass more sharply following extremely dry or wet seasons. This could be a short-term response to changes in their environment, such as a lack of rainfall causing a decline in the number of insects that the birds feed on. But wingspan was significantly larger in one third of the species and the wing-to-mass ratio significantly smaller in two thirds of them, suggesting that the mechanisms behind the change could be complex and genetic rather than temporary. “Mass is a generally good index of body condition in birds,” says Jirinec. “If they are simply not getting enough to eat, you would expect them to lose weight. But why would they have more energy to grow their wings?”
11-12-21 The Amazon's pink river dolphin population is in freefall
The population of botos, river dolphins found in the Brazilian Amazon, is declining due to fishing with gill nets and is predicted to fall by at least 95 per cent in less than 50 years. Strange, pink, small-eyed freshwater dolphins glide through today’s turbid waters of the Amazon River basin. But they are speedily approaching extinction. The Amazon river dolphin, or “boto” (Inia geoffrensis) is one of the few remaining dolphins on the planet that are restricted to freshwater, with two other superficially similar species persisting in South Asia. Anthony Martin at the University of Dundee in Scotland and his colleagues have spent more than two decades studying the botos around Mamirauá Sustainable Development Reserve in the Brazilian Amazon. Using their wealth of long-term data, Martin and Vera da Silva at the National Institute of Amazonian Research in Brazil calculated how the population was trending. The team used 22 years of survival and reproductive data on more than 650 dolphins to create a model that predicts the botos’ population size in the coming decades. “When we first started this work, there were dolphins everywhere, and we thought of them as actually very abundant,” says Martin. But their model delivered a shock. “It knocked our socks off,” says Martin. “The decline is far more profound than we had imagined.” In all six of their simulations, the dolphins’ numbers are predicted to fall by at least 95 per cent in less than 50 years. The extinction of the boto may occur in just over a century. In this part of the central Amazon, the botos’ precipitous decline is largely due to entanglement and drowning in monofilament gill nets, and people catching and using the dolphins as fish bait. Martin says that the boto is treading the same path as the baiji, a river dolphin native to the Yangtze River in China that is likely now extinct. “All of the true river dolphins – the ones that can’t get away from humans – they’re all going down the plughole.”
11-11-21 Deep-sea rockfish that live to be 200 hint at genes for longevity
Longevity research often focuses on short-lived lab animals like mice – but a study of long-lived rockfish might offer new genetic clues for extending lifespans. Rockfish are among the longest-living animals known to exist, and by studying the natural variation in their lifespans, researchers have discovered key insights into the genetic basis of longevity. Studies into ageing have traditionally focused on laboratory mice because they are easy to work with. However, Peter Sudmant at the University of California, Berkeley, and his colleagues adopted a different approach, studying longevity in creatures with longer lifespans. The researchers performed a genomic analysis of 88 species of Pacific Ocean rockfish (genus Sebastes) – deep-sea creatures that live between 11 and 200 years – to map out the genetic underpinnings of their lifespans. They accounted for factors such as body size and their environment, which are variables that are known to affect ageing in many organisms. “We found genes associated with many different pathways — genes involved in DNA repair, metabolism and immune response,” says Sudmant. It is possible that a set of genes called butyrophilins, which are known to influence many human diseases of inflammation, contribute to the extreme lifespan of long-lived rockfishes. “We found that these genes, which we think play an immunosuppressive role, have higher ‘copy number’ [meaning some have been duplicated] in ultra-long-lived species,” says Sudmant. “This highlights a specific set of genes and pathways that might be important to follow up in humans.” An investigation into the lives of these long-lived animals is critical to learning how to enhance and prolong human health, says Steven Austad at the University of Alabama at Birmingham. “I don’t believe we will make much headway in extending human health if we only study short-lived organisms like fruit flies and mice.”
11-10-21 Chimpanzees dislike the smell of death like we do
Some chimpanzees will carry around an infant that did not survive, which made researchers wonder if they are as sensitive to the chemicals that produce odours in dead bodies. Chimpanzees avoid the smell of dead things, much like we do. This odour may play a key role when chimpanzee mothers grieve their young. It is thought that humans and some other animals evolved disgust for putrescine – the chemical odour compound associated with decomposing bodies – to protect them from disease or predation by scavengers. However, nobody had tested whether chimpanzees were sensitive to the smell of death, says James Anderson at Kyoto University in Japan. He and his colleagues investigated this with two female and four male chimpanzees, all aged between 24 and 48 years old, that were housed in Kyoto University’s Kumamoto Sanctuary. One night a week over a six-week period, the chimpanzees returned to their cages after roaming in the sanctuary to find either a stuffed dead bird or a stuffed glove in a cardboard box just outside their cages. The researchers dispersed odours from a bucket, using a fan to waft the scents of water, putrescine or other substances. The chimpanzees avoided the object significantly more when putrescine was diffused, regardless of whether it was a bird or a glove, says Anderson. “With the putrescine, it was clear that the chimps wanted away from there,” he says. The two oldest individuals, aged 46 and 48, were the least repulsed by the smell of putrescine. Chimpanzee mothers sometimes carry dead infants for weeks or months. The researchers didn’t test such mothers, but they suspect that these apes accept the odours due to attachment to their infants, or they might just get used to the smell. Post-partum chimpanzees may also have a reduced sense of smell, but studies would be needed to test this, says Anderson. Eventually, often at a time when the putrescine odour would be the strongest – around two to four days after death – chimpanzee mothers abandon their dead babies, says Anderson.
11-10-21 Cats can mentally map their owner’s location from voice alone
In tests with hidden loudspeakers, cats show signs of being surprised when their owner’s voice seemed to quickly "teleport" from one side of a room to another. Domestic cats can mentally map their owner’s location simply from the sound of their voice. Previous studies of cats (Felis catus) have revealed they are able to track objects that move out of sight – showcasing a level of what is known as “object permanence”, the recognition that an object continues to exist even if it can no longer be seen. But few studies have tested how cats use their other senses to track objects and individuals. Saho Takagi at Kyoto University in Japan and her colleagues put cats’ hearing to the test by investigating how they responded to their owner’s voice. To do so, they studied 50 domestic cats – 27 of which live at “cat cafes” where people can pay to watch and play with cats, while the remaining 23 were house cats. The team placed each cat alone in a test room with two doors and a window. They placed a speaker outside the room near one door and a second speaker outside near the second door or the window. The two speakers were at least 4 metres apart. To observe the cats, the team set up five video cameras in the room. Read more: Cats refuse to snuggle with objects that smell like their owners During each test, the researchers used the speakers to play recordings of the cat’s owner – whether a cafe owner or a member of the household – or a stranger calling the cat’s name. The voice was played twice, 2.5 seconds apart, and could come from either the same speaker both times or once from each speaker. Eight people then evaluated each cat’s response by carefully analysing the video footage. The results suggest that cats show little surprise – indicated by moving their ears or changing head direction – when their owner’s voice was played twice from the same speaker, or when the stranger’s voice was played either twice from the same speaker or once from each speaker.
11-10-21 Asian honeybees scream in alarm when giant hornets attack the hive
Asian honeybees produce what has been described as a disturbing scream-like sound when their hive is attacked by giant hornets. A frenzied alarm signal produced by a type of Asian honeybee during a giant hornet attack has been identified for the first time. Hornets are Asian honeybees’ most devastating predators and can wipe out entire colonies. Heather Mattila at Wellesley College in Massachusetts and her colleagues recorded sounds inside hives containing Asian honeybees (Apis cerana) as they came under attack either by a type of giant hornet (Vespa soror) related to the infamous “murder” hornet (Vespa mandarinia), or a smaller hornet species (Vespa velutina). The team also recorded sounds from the hives in the absence of predators. In total, the researchers captured nearly 30,000 bee signals in more than 1300 minutes of recording, from three beekeeping yards in Hanoi, Vietnam. By analysing pictures of the sound patterns, the team discovered that bees produce a previously undescribed set of harsh and irregular noises that can change rapidly in frequency when giant hornets, but not smaller hornets, arrive at the hive. They named these signals “antipredator pipes”. No such sounds were detected in the absence of threats. “I found it really disturbing. When you analyse the recordings, part of you is scared for the bees, and part of you is so excited for how unusual these sounds were,” says Mattila. The acoustic properties are very similar to alarm shrieks and fear screams made by other animals like primates and birds, says Mattila. Using cameras to film the hive entrances, the team found that the antipredator pipes seemed to rally more bees to the hive entrance. Once here, the bees placed more animal dung around colony entrances, a behaviour known to deter hornets. The arrival of smaller hornets didn’t lead to increased dung-depositing by the bees.
11-10-21 Researchers have unlocked the secret to pearls’ incredible symmetry
The discovery could inspire more optimal materials for solar panels and space travel. For centuries, researchers have puzzled over how oysters grow stunningly symmetrical, perfectly round pearls around irregularly shaped grains of sand or bits of debris. Now a team has shown that oysters, mussels and other mollusks use a complex process to grow the gems that follows mathematical rules seen throughout nature. Pearls are formed when an irritant gets trapped inside a mollusk, and the animal protects itself by building smooth layers of mineral and protein — together called nacre — around it. Each new layer of nacre built over this asymmetrical center adapts precisely to the ones preceding it, smoothing out irregularities to result in a round pearl, according to an analysis published October 19 in the Proceedings of the National Academy of Sciences. “Nacre is this incredibly beautiful, iridescent, shiny material that we see in the insides of some seashells or on the outside of pearls,” says Laura Otter, a biogeochemist at the Australian National University in Canberra. A pearl’s symmetrical growth as it lays down layers of nacre relies on the mollusk balancing two basic capabilities, Otter and her colleagues discovered. It corrects growth aberrations that appear as the pearl forms, preventing those variations from propagating over the pearl’s many layers. Otherwise, the resulting gem would be lopsided. Additionally, the mollusk modulates the thickness of nacre layers, so that if one layer is especially thick, subsequent layers will be thinner in response (SN: 3/24/14). This helps the pearl maintain a similar average thickness over its thousands of layers so that it looks perfectly round and uniform. Without that constant adjustment, a pearl might resemble stratified sedimentary rock, amplifying small imperfections that detract from its spherical shape.
11-9-21 Newly recognised octopus species described in south-west Australia
Octopus djinda is caught in fisheries and eaten by people, but has only now been recognised as a separate species from another Australian octopus. A new species of octopus has been described in south-west Australia, after a study determined it is different enough from its eastern Australian relative to be considered taxonomically distinct. Although the species has only now been given its own name, people have long been catching and eating the animal, which supports one of the world’s few sustainable octopus fisheries. The new species has been named Octopus djinda, following consultation with the Aboriginal Advisory Committee of the Western Australian Museum in Perth. Djinda means “star” in the Nyungar language. The octopus is found along the south-west coast of Australia. It was previously believed to belong to the O. tetricus species that lives along Australia’s east coast and New Zealand, but Michael Amor at the Western Australian Museum and Anthony Hart at the Western Australian Fisheries and Marine Research Laboratories have found that O. djinda has more suckers along its arms. “It may not sound like much,” says Amor, but when trying to identify species of octopus hiding in plain sight, “a few suckers can be a big deal”. Genetic analysis also suggests that the octopus is sufficiently distinct from O. tetricus to be considered a separate species. O. djinda is targeted by the Western Australia octopus fishery, which is the largest and fastest-growing such fishery in Australia. But it has appropriate catch limits, says Amor, and is one of only two octopus fisheries worldwide that has been certified as sustainable by the Marine Stewardship Council. However, it is often the case that many types of octopus are lumped together in fishing statistics, which makes it difficult to assess how many of a particular species are being caught. “This is a major problem when trying to interpret catch trends, especially with increasing fishing pressure and climate change,” says Amor. “Now that O. djinda is formally recognised as a species and, importantly, distinguished from O. tetricus, formal catch statistics reporting can proceed at the species-level in Australia and globally,” he says.
11-9-21 Some songbirds now migrate east to west. Climate change may play a role
A dramatic shift in some Richard’s pipits’ winter plans might be linked to a warming Europe. As the chill of autumn encroaches on Siberia’s grasslands, Richard’s pipits usually begin their southward trek to warmer latitudes. But a growing number of the slender, larklike songbirds seem to be heading west instead, possibly establishing a new migratory route for the species. This would be the first new route known to emerge on an east-west axis in a long-distance migratory bird, researchers report October 22 in Current Biology. The finding could have implications for how scientists understand the evolution of bird migration routes over time and how the animals adapt to a shifting climate. Richard’s pipits (Anthus richardi) typically breed in Siberia during the summer and travel south for the winter to southern Asia. Occasionally, “vagrant” birds get lost and show up far from this range, including in Europe. But as a Ph.D. student at the Université Grenoble Alpes in France, evolutionary biologist Paul Dufour noticed, along with colleagues, that described sightings and photo records of the pipits wintering in southern France had increased from a handful of birds annually in the 1980s and 1990s to many dozens in recent years. So, Dufour, now at the University of Gothenburg in Sweden, and his team started monitoring the pipits in France and Spain to see where the birds were coming from, and if the birds were visiting Europe on purpose or just getting lost. The researchers captured seven pipits in France during the winter of 2019–2020, tagging them with a sensor that estimates the birds’ geographic positions based on light levels and length of day. The team then released the birds. The next winter, the team successfully recaptured three of them. Those sensors showed that the birds had all flown back to the same part of southwestern Siberia for the summer before returning to France.
11-8-21 Wild honeybees believed to have been wiped out discovered in ancient woodlands
A bee conservationist made an unexpected discovery in the ancient woodlands surrounding Blenheim Palace in England. Filipe Salbany found hundreds of thousands of rare honeybees that appear to be the last wild descendants of Britain's native honeybee population, The Guardian reports. These bees are smaller, furrier, and darker than their counterparts that live in managed beehives, and they "live in nests in very small cavities, as bees have for millions of years," Salbany said. In the early 1990s, the varroa mite arrived in Britain and was thought to have wiped out the wild honeybee population, but Salbany said he believes the bees he came across have evolved to survive such threats. DNA samples have been extracted from the bees for testing, and Salbany said it's clear their wings are smaller and their veins are "very distinct," distinguishing them from imported bees. The woodlands are not open to the public and there is no gardening or planting activity, so there is "very little human interaction," Salbany told The Guardian. The bees are so relaxed that he's able to touch them safely, and they make "incredibly pure" honey. Salbany said he thinks it's likely there are other spots with hidden wild bee populations, and that's why "we need to protect our ancient woodlands. Because that's where we are likely to find these bees."
11-6-21 Watch first footage of Asia’s long-lost bird, the black-browed babbler
The black-browed babbler had been missing for 172 years before its unexpected rediscovery last year – now we have our first footage of the bird in the wild. The enigmatic black-browed babbler has been studied in the wild for the first time following its reappearance after a 172-year absence. No Asian bird has been missing for as long as the black-browed babbler (Malacocincla perspicillata) was before its rediscovery in 2020. Following the unexpected first sighting, Panji Gusti Akbar from Birdpacker, a birdwatching group in Indonesia, and his colleagues set out in September 2021 to explore the enigmatic bird’s habitat in the limestone hills of Kotabaru Regency, in Indonesian Borneo. The team spotted a pair of babblers in dense shrubbery near the side of the cliffs. Akbar noted that the birds moved very quietly and discreetly, which may be the reason they were hidden from us for so long. Once the birds were close enough, the team captured the first images and videos of the birds in their natural habitat. The babbler can be identified by a prominent bill, grey and brown feathers, and a distinctive black eyestripe. Before its rediscovery, our only evidence of the bird’s existence came in the form of a single stuffed specimen and a number of natural history accounts dating back to the mid-19th century. Akbar said in a statement: “It was a breathtaking moment to finally see this species in the wild, as most of its natural history is entirely unknown, so that every single behaviour we observed can be new to science.” Paul Insua Cao, chair of the Oriental Bird Club’s conservation committee, said in a statement that the rediscovery spotlights the biodiversity crisis happening around the world. The black-browed babbler would probably have become extinct had it not been for its rediscovery, as we can now start looking to protect its habitat, said Cao.
11-4-21 Baleen whales eat (and poop) a lot more than we realized
In a single day, a blue whale can gulp down the caloric equivalent of 30,000 Big Macs. Whalers have plucked giant whales from the sea for much of the last century, reducing their numbers by up to 99 percent for certain species. Some scientists thought that krill — the tiny crustaceans that many whales eat in gargantuan gulps — would explode in number as a result, mostly free from the feeding pressure of the largest animals that have ever lived. But that didn’t happen. Instead, Antarctic krill numbers have dwindled since the mid-20th century, by more than 80 percent in areas heavily trafficked by whalers. Many other consumers of krill, like seabirds and fish, have suffered too in the absence of the crustaceans and their giant eaters. Now, scientists have a clearer idea why this happened: whale poop, or rather, the lack of it. A new study finds that baleen whales, including blue and humpback whales, eat on average three times as much krill and other food as previously thought, and more food in means more poop out. Paradoxically, the collapse of the krill may stem from fewer whales excreting iron-rich, digested krill, denying these ecosystems some crucial nutrients they need to thrive. Phytoplankton blooms, which sustain krill and many other parts of the food web, rely on that iron. Restoring whale populations to prewhaling levels could help bolster these ecosystems and even store more carbon in the ocean, researchers report in the Nov. 4 Nature. “It’s hard to know what role whales play in ecosystems without knowing how much they’re eating,” says Joe Roman, a marine ecologist at the University of Vermont in Burlington who wasn’t involved in the research. Whale food intake was coarsely understood before, he says, and this study will “allow us to better understand how the widespread depletion of whales has impacted ocean ecosystems.”
11-3-21 Baleen whales eat three times more krill than we thought
Baleen whales are the largest animals on Earth, and they are even hungrier than we had assumed, which has huge implications for marine ecosystems. Baleen whales, the largest animals in the world, eat three times more prey than previous estimates suggested. The discovery implies that these whales play a larger role in sustaining marine ecosystems than we had thought. Matthew Savoca at Stanford University in California and his colleagues tracked 321 tagged baleen whales from seven species, including the blue whale (Balaenoptera musculus), the fin whale (Balaenoptera physalus) and the humpback whale (Megaptera novaeangliae). The researchers followed these whales throughout the Atlantic, Pacific and Southern Oceans and estimated their feeding patterns using aerial photographs of the whales’ foraging areas and acoustic measurements of prey density, primarily crustaceans such as Antarctic krill (Euphausia superba). The team found that the average amount of prey consumed per day by the seven baleen species was between 5 and 30 per cent of their body mass – a range that is three times higher than previous average estimates. In the Southern Ocean, the team estimated baleen whales ate around 430 million tonnes of krill per year before industrial whaling began in the early 20th century. This is twice the estimated mass of krill in our oceans today. “This new higher estimate is important for the functioning of ocean ecosystems because whales act as giant nutrient recycling plants,” says Savoca, “By consuming even more prey than previously thought in most cases, they are also pooping more, and that poop is actually marine fertiliser.” This fertiliser sparks the growth of marine plants, including phytoplankton, and provides food for krill and other small fish.
11-3-21 Do you speak elephant? With this new dictionary you will
An ambitious directory of elephant behaviours and vocalisations offers amazing insights into their minds and culture – and could help save these magnificent beasts from extinction. A HERD of around 40 elephants processes across open grassland in Mozambique’s Gorongosa National Park. Led by a matriarch named Valente, they are headed towards a newly felled tree, a potential food source. The tree is out of sight: perhaps the elephants detected vibrations from the impact through their feet. That’s cool, and the procession is impressive – but elephant scientist Joyce Poole isn’t sure why this particular video went viral. Since May, she and her husband Petter Granli have been posting clips of elephants daily on social media, and others are far cuter or odder. The duo are co-founders of a US-based non-profit organisation called ElephantVoices, and these videos are part of a project they have been working on for the past five years. Called the Elephant Ethogram, it is a freely available online library of elephant behaviours and vocalisations, along with their meanings. Since it went live, Poole and Granli have been inundated with messages expressing wonder and gratitude. This shouldn’t come as a surprise. The human desire to decipher other animals is ancient, and science has recently brought that dream closer – through, for example, the use of artificial intelligence to start decoding the vocalisations of whales and birds. The Elephant Ethogram is less flashy, but far more impressive. Andrew Whiten, who studies animal behaviour at the University of St Andrews, UK, calls it a “staggering achievement”. It is probably the most ambitious ethogram ever created. As well as giving anyone the pleasure of understanding elephants more intimately, it could transform the way researchers see these magnificent animals – and even help avert their extinction.
11-3-21 Bats’ landing styles differ depending on where they roos
An analysis of 35 bat species found in Central America, Bulgaria and China shows that the landing style each species takes is related to the make-up of their roost. Bats are unique among mammals thanks to their ability to fly, but what goes up must come back down. An analysis of bats’ landing methods has revealed that their touchdown techniques can give insights into other aspects of their lifestyle, such as the kind of shelter they live in. “If you’re going to be able to fly, you have to be able to land without dying,” says David Boerma at the American Museum of Natural History in New York City. Pulling off a safe landing is tied directly to a critical resource: the roosts where bats seek shelter and raise their young. Roosts provide protection and a social life, and act as an anchor for how bats interact with their surrounding environment. While at Brown University in Rhode Island, Boerma and his colleague Sharon Swartz, also at Brown University, investigated the mechanics of bat landings by recording footage of 665 landings from 35 species of bats, mostly at field sites in Central America, Bulgaria and China. They then compared the bats’ landing techniques with the properties of their roosts and the evolutionary relationships between the species. The pair found that a bat’s landing style was related to the physical properties of the landing surface, rather than the roost’s location. Boerma was surprised, as he originally expected that bat species that were closely related or had around the same body size would land similarly regardless of their roost characteristics. Some bats landed with a flip as they grasped the surface with their feet. This approach seems to have evolved multiple times and is linked to stiff, horizontal roosts, like cave ceilings. Four-point landings, in which the bat touches down with all four feet at once, are the simplest and oldest method, derived from the grappling descent of gliding ancestors, and were common with surfaces like foliage that have a bit more give. Some three-point landings worked well in cramped situations.
11-3-21 Dogs may get worse separation anxiety when left alone with another dog
Some dogs will bark and howl when left alone by their owner, but an analysis of video footage shows getting a second dog may make the problem worse. Dogs living with other dogs often bark more than those in single-dog households when their owners leave home for a few hours – and they whine and howl just as much. The discovery suggests that getting a second dog might not be a reliable way to resolve the anxiety that some dogs experience when they are separated from their humans. It also overturns a popular belief that dogs that are separated from their owners but are in the company of others of their kind are “not that alone”, says Gerrit Stephan at the Academy for Animal Naturopathy in Switzerland. “We do not suggest that dogs in single-dog households [in general] are better off when left alone, but we observed more separation-related behaviour in multi-dog households,” he says. “Canine company may help dogs cope with separation from human attachment figures in individual cases, but our results indicate that this is not granted and should be checked carefully by owners.” In fact, because one dog barking can set off barking in other dogs, a person attempting to calm separation anxiety in their first dog by getting a second one might make the situation worse, he says. Stephan and his colleagues reached these conclusions after studying videos captured inside the homes of dog-owners and recording dogs’ reactions when their humans left the house without them as part of their regular routine. They looked at footage of 32 dogs living alone and 45 dogs living with others. Most of the time, the dogs lay around doing nothing, says Stephan. Minor activity – like sitting or standing still, or raising their head – took up 22 per cent of their time, and the animals were actively moving around for less than 2 per cent of the time.
11-3-21 Red feathers determine which common waxbill is the boss
For a songbird called the common waxbill, dominance isn't governed by body size, intelligence, or even temperament, but by the intensity of the colours in their chest feathers. Common waxbills with the highest social ranks aren’t necessarily larger or more intelligent than their peers – but they do have chest feathers that are a richer shade of red. This may be because individuals are so healthy that they can spare resources on accentuating their colours. Patrícia Beltrão at the University of Porto in Portugal and her colleagues discovered this by evaluating dozens of common waxbills (Estrilda astrild) that were captured as adults in a large outdoor netted area. The researchers measured the birds’ body size and then used digital photography and reflectance spectrophotometry to determine the size and saturation levels of the red-feathered chest patches. They also ran standard behaviour tests on each bird to judge their intelligence, stress tolerance and level of aggression or passivity. Then, they monitored bird feeders in the netted area, recording when a bird recognised another as higher-ranking by giving up its place at the feeder. The researchers found that the only obvious factor linked with rank and dominance was the saturation level of the red chest plumage, says Beltrão. If a bird has more saturated red colouring, it could indicate that it is healthy enough to spare nutrients in food for pigment use, so the feathers could act as a “badge of honour”, says Beltrão. “But that’s just a hypothesis.”
11-3-21 Vampire bats that live together share a common gut microbiome
Vampire bats form tight social groups and even share regurgitated food – and doing so means the bats end up with a similar gut microbiome. Microbes may be transferred between vampire bats when they lick and groom one another and share regurgitated food – and this means the bats living together end up with a common “social microbiome”. What’s more, within each colony, the more one bat touches another with its mouth and tongue – a sign of how socially close the pair are – the more the pair’s microbiota align with one other, says Gerald Carter at the Ohio State University in Columbus. “Their relationships map right onto their microbiome similarity.” Carter and his colleagues ran DNA sequencing on faecal samples from common vampire bat (Desmodus rotundus) colonies in six US zoos and one wild colony in Belize. They also took faecal and inner gut samples from an experimentally grouped colony of bats, which originally lived in three separate wild colonies in Panama and were then housed together for four months. For this last group, they also ran infrared video recording for six hours a day throughout the experiment to observe social contacts, especially licking. Bats living in the same colony – whether in the wild or in zoos – typically had gut microbiomes that were similar to each other and dissimilar to those from other colonies, in terms of the microorganisms present and their relative abundances, says Carter. Despite living together for only four months, the microbiomes of bats in the experimentally merged group were also similar to each other, but less so than those in the natural colonies in zoos and in the wild. The more physical – and especially oral – contact there was between any two bats in that colony, the more similar their microbiomes were. The findings suggest that while bats might get their gut microbiota from their parents, their environment and their diet (which is exclusively blood), their microbiomes can change easily and rapidly to line up with those of bats in their social community, says Carter.
11-3-21 Nursery web spiders woo mates with food wrapped in chemical-laced silk
Chemicals in the silk of male nursery web spiders help them attract a mate when used as gift wrap. Male nursery web spiders persuade females to mate by wrapping food in their own silk, which is laced with attractive chemicals. This gift-giving is a common part of courtship among nursery web spiders (Pisaura mirabilis), but Michelle Beyer and her colleagues at the Ludwig Maximilian University of Munich in Germany wanted to find out more about how it works. The team gave freshly euthanised houseflies to P. mirabilis male spiders and allowed them to wrap the prey in silk. They then either unwrapped the fly before submerging the silk in ethanol and water and then re-wrapping a fresh fly inside, or left the gifts untouched. They also prepared unwrapped dead flies as a control. The researchers used tongs to offer the food gifts to 35 female spiders and found that unwashed gifts were accepted around 75 per cent of the time, while washed gifts were accepted around 40 per cent of the time, suggesting that molecules on the unwashed silk swayed the females towards gift acceptance, though exactly which substances is unclear. “Since both ethanol and water are known to remove, among others, acids, esters, alcohols or ketones, I would expect the chemicals involved to belong to one of these groups. If the females are satisfied with what they sense, for example chemical presence or concentration, they could indeed feel more attracted to the males,” says Beyer. The unwrapped control gifts were only accepted around half the time, supporting the idea that chemicals in the silk make the giver more attractive. “Females accepted wrapped gifts more often than a dead fly in plain view,” says Beyer. It is possible that the chemicals require a lot energy to produce, suggesting that the amount of chemicals present indicates how healthy a male is, helping females to pick the fittest mates, says Beyer.
11-2-21 Falling bird numbers mean quieter birdsong in Europe and North America
The natural soundscape of birdsong has probably become quieter in Europe and North America over the past 25 years because of a decline in bird numbers. Springtime birdsong may be becoming quieter and less diverse in North America and Europe due to declining bird populations, which is bad for ecological diversity and may also have a negative impact on human health and well-being. Natural soundscapes are an important way to connect people with nature, and doing so has been shown to benefit both our physical and mental well-being. The familiar trills, whistles and caws of birds are a major component of these soundscapes. Simon Butler at the University of East Anglia in Norwich, UK, and his colleagues compiled bird count data from 202,737 sites in North America and 16,524 sites in Europe, collected between 1996 and 2018. The team then used the data and recordings of 1067 bird species taken from an online database to reconstruct the likely bird soundscape that existed at each site for every year. For each individual bird spotted at a site on a particular year, 25-second clips of their songs were randomly inserted by the team into an empty 5-minute sound file. The volume of individual birds was also randomly sampled to represent birds singing from different distances. “Ideally, it should sound like had you taken a recorder out into the field as the person was doing the bird survey,” says Butler. The researchers then analysed the clips with acoustic modelling, which quantified the songs’ acoustic characteristics, including the volume and pitch, and the amount of variation in these properties. They found a significant decline in the diversity and intensity of birdsongs across both continents over the past 25 years, which means soundscapes in these regions have become quieter and less varied. The results reflect widespread declines in bird populations and biodiversity in North America and Europe over the same period.
11-2-21 Grumpy and aggressive shelter cats become more friendly over time
Some animals can develop problematic behaviours the longer they stay in an animal shelter, but cats tend to become friendlier and less aggressive. Many unfriendly or aggressive shelter cats can become much more sociable with humans – and hence more adoptable – if just given time. Unlike dogs, which can develop problematic behaviours and appear less sociable as they spend more time in animal shelters, cats tend to become friendlier the longer they stay. Cats may need the extra weeks or even several months to recover from stress, veterinary issues or the change in environment that make them less approachable, says Veronika Vojtkovská at the University of Veterinary Sciences Brno in the Czech Republic. Vojtkovská and her colleagues rated the sociability of 158 cats entering an animal shelter over a 12-month period in the Czech Republic, where euthanasia for non-veterinary reasons is illegal. The animals lived indoors in a group of about 25 cats at a time with access to an outdoor enclosure. The cats – all at least 3 months old – underwent their first evaluation after an approximately 14-day quarantine, and then again every two weeks as long as they stayed at the shelter. At the first evaluation, most of the cats were rated as friendly or very friendly, the highest scores on a 5-point scale. Over time in the shelter, these cats either stayed just as friendly or became even friendlier. However, nearly 20 per cent of the incoming cats were initially rated as neutral, unfriendly or so unfriendly that they couldn’t be touched. Of these, more than half showed permanent improvement over time – sometimes taking several months. The longer the cats stayed, the more social they became. “This work supports the idea that human interaction is an important aspect of a shelter cat’s social life,” says Kristyn Vitale at Unity College in Maine. “It is possible that as cats get more comfortable in their surroundings and new routines, they also feel more confident to engage in a higher diversity of behaviours, such as engaging in social behaviour with people,” says Vitale.
11-1-21 Barn owls make mental maps of their surroundings while they are flying
Neurons that help humans make mental maps, called place cells, have now been seen in flying birds for the first time. Owls may make maps of their surroundings in their brains just like humans do. The fact that this ability has been seen in mammals and non-mammals could suggest it evolved hundreds of millions of years ago. Yoram Gutfreund at Technion-Israel Institute of Technology and his colleagues implanted a wireless neural recording device into the brains of six barn owls (Tyto alba), using these to analyse brain activity as they flew back and forth between two perches. The researchers were looking for evidence of place cells – neurons that fire when an animal visits a specific place. These cells let an animal make a mental map of its surroundings and have been found in humans, rodents and bats. They have never been recorded in flying birds before, although they have been seen in a tufted titmouse, a type of songbird, as it walks. The team recorded each bird for about 20 minutes, tracking flight with eight high-speed infrared cameras, repeating the experiment several times with each bird. By combining data from the owls’ brains with the infrared recordings, the team found that certain hippocampus neurons fired more strongly at specific points in the flight path and depending on which direction a bird was going in. This response was unaffected by lighting changes or movements by the experimenter in the room. Place cells in rodents display similar behaviour. But the team notes that the cells could instead be time-sensitive and their firing dependent on how long the birds have been in the air. Cells have been found in rodents that fire at distinct time points after the initiation of an action.
11-1-21 Gene-edited stem cells help geckos regrow more perfect tails
Experiments coaxed the geckos to regrow tails with some nerve tissue and bonelike cartilage. Regenerating body parts is never easy. For instance, some lizards can grow back their tails, but these new appendages are pale imitations of the original. Now, genetically modified stem cells are helping geckos grow back better tails. Tweaking and implanting embryonic stem cells on the tail stumps of mourning geckos (Lepidodactylus lugubris) allowed the reptiles to grow tails that are more like the original than ever before, researchers report October 14 in Nature Communications. These findings are a stepping-stone to developing regenerative therapies in humans that may one day treat hard-to-heal wounds. A gecko’s tail is an extension of its spine — with the vertebrae to prove it. Regenerated tails, however, are simpler affairs. “It’s just a bunch of concentric tubes of fat, muscle and skin,” says Thomas Lozito, a biologist at the University of Southern California in Los Angeles. That’s because stem cells in adult geckos produce a molecular signal that encourages the formation of cartilage in new tails, but not bone or nervous tissues (SN: 8/17/18). Lozito and his colleagues used embryonic stem cells, which can develop into a wider range of tissues than adult stem cells, modified them to ignore this signal and then implanted them on the tail stumps of geckos that had their tails surgically removed. The tails that grew from these modified stem cells had bonelike grooves in the cartilage and generated new neural tissue at the top of the tail. These modified tails still lack a spinal cord, making them a far cry from the original. “We fixed one problem, but there are still many imperfections,” Lozito says. “We’re still on the hunt for the perfect tail.”
11-1-21 New Zealand bat flies away with bird of the year award
A bat has been named as New Zealand's bird of the year, in a controversial move that has ruffled feathers. The long-tailed bat had swooped in to clinch the title in an online poll. Contest organisers had included the bat, one of the country's few land-based native mammals, to raise its profile as a critically endangered species. But the victory has annoyed some, with one commenter saying the country had gone "batty". Outraged bird-lovers cried fowl on Twitter, calling it a "total farce", a "stolen election", as well as more colourful and unprintable terms. Some on social media also saw it as a much-needed public relations victory for bats, after a particularly trying two years. But environmental group Forest and Bird, which organises the competition every year, said the bat's inclusion was not a bid to restore its image in the wake of the coronavirus pandemic. Spokesperson Laura Keown said in a statement that "a vote for bats is also a vote for predator control, habitat restoration, and climate action to protect our bats and their feathered neighbours!" The Bird of the Year contest has been seen as a way to raise awareness of New Zealand's biodiversity and species that are under threat. In apparent defiance of the laws of scientific taxonomy, Forest and Bird had decided to include a land mammal for the first time this year, saying they faced similar challenges as birds. The long-tailed bat, also known as the pekapeka-tou-roa and is only the size of a thumb, beat a flightless parrot to win the title. More than 56,700 people cast their votes, with more than 7,000 for the bat and just over 4,000 for the kakapo, which won the contest last year. This is not the first time the contest has flown into controversy. In 2019, hundreds of votes were found to have come from Russia, spurring fears of voter fraud. Organisers later determined that they were likely to have come from Russian bird-lovers, instead of hackers intent on manipulating the vote.