4-30-21 Wild horses and donkeys dig desert wells that boost biodiversity
Feral horses and donkeys in the Sonoran desert in North America dig their own wells, inadvertently providing a water source for other animals and increasing biodiversity in the area. Erick Lundgren at Aarhus University in Denmark and his colleagues monitored four separate streams in part of the Sonoran desert in Arizona. The streams are usually supplied by groundwater but dry up in the summer. The team surveyed each stream every few weeks over the summers of 2015, 2016 and 2018, and found that horses and donkeys in the area dig wells there to access the groundwater. “It’s a very hot, dry desert and you’ll get these pretty magical spots where suddenly there is surface water,” says Lundgren. The horses and donkeys dig wells up to 2 metres in depth to access water. The team saw 59 other vertebrate species at the wells, 57 of which were recorded drinking from the wells. On average, species richness was 51 per cent higher at these wells than observed in nearby dry areas during the same time periods. “These resources are in fact used by all other animals – there was a cacophony of organisms,” says Lundgren. This included squirrels, mule deer, quails and even a black bear at one point, he says. The wells also function as germination points for plants, especially riparian pioneer trees. These horses and donkeys provide a useful source of water for a range of species, which is especially important given that deserts are becoming hotter and drier as a result of climate change. Despite this find, large herbivores are often seen as threats to conservation and biodiversity. “Some research from the western United States has shown that feral horses exclude native wildlife from water sources in deserts,” says Lucas Hall at California State University, Bakersfield. “The benefit they may provide by creating new water sources will likely be offset by their high populations and exclusionary effects on other wildlife.”
4-30-21 Wild donkeys and horses engineer water holes that help other species
Often cast as invasive pests, the equids may actually benefit some ecosystems. Water drives the rhythms of desert life, but animals aren’t always helpless against the whims of weather. In the American southwest, wild donkeys and horses often dig into the dusty sediment to reach cool, crystal clear groundwater to quench their thirst. New research shows this equid ingenuity has far reaching benefits for the ecosystem. Equid wells can act as desert oases, providing a major source of water during dry times that benefits a whole host of desert animals and keystone trees, researchers report in the April 30 Science. Introduced to North America in the past five hundred years or so, wild donkeys and horses are often cast as villains in the West. These species can trample native vegetation, erode creek beds and outcompete native animals. But when Erick Lundgren, a field ecologist at Aarhus University in Denmark, first observed wild donkeys digging wells in 2014, he wondered whether these holes might benefit ecosystems, similar to the way elephant-built water holes can sustain a community in the African savannah. “Because of the way we value [feral] horses and donkeys, the orthodoxy tends to focus on how they harm ecosystems,” he says. “We wanted to see whether these holes provided a resource when water is scarce.” First, Lundgren and his colleagues had to see whether these holes actually increase accessible water. Over the course of three summers from 2015 to 2018, they mapped out the surface area of water in wells and groundwater-fed streams at four sites in Arizona’s Sonoran Desert. Water availability was highly variable among sites, but equid wells generally increased accessible water, especially as temperatures rose. At one site, wells were the only source of drinking water once the stream completely dried up. Elsewhere, wells provided up to 74 percent of available surface water. Wells also decreased the distance between water sources by an average of 843 meters, making this essential resource more accessible and easing tensions that can escalate among drinkers at isolated water holes, Lundgren says. Once wells were dug, other animals came. In droves.
4-30-21 Mantis shrimp start practicing their punches at just 9 days old
Glass-bodied young mantis shrimp reveal key secrets of their speedy weapons. The fastest punches in the animal kingdom probably belong to mantis shrimp — and they may begin unleashing these attacks a little more than a week after hatching, when they have just started to hunt prey, a new study shows. For the first time, researchers have peered through the transparent exoskeletons of these young mantis shrimp to see the inner mechanisms of their powerful weapons in motion, researchers report online April 29 in the Journal of Experimental Biology. The findings are letting scientists in on hidden details of how these speedy armaments work. Mantis shrimp are equipped with special pairs of arms that can explode with bulletlike accelerations to strike at speeds of up to roughly 110 kilometers per hour. Previously, scientists deduced these weapons act much like crossbows. As a latch holds each arm in place, muscles within the arm contract, storing energy within the arm’s hinge. When the crustaceans release these latches, all this energy discharges at once (SN: 8/8/19). But researchers didn’t know at what age mantis shrimp first begin launching these spring-loaded attacks. Computer simulations predicted that the armaments might be capable of greater accelerations the smaller they got, suggesting young mantis shrimp could actually have faster weapons than adults, says Jacob Harrison, a marine biologist at Duke University. To solve this mystery, Harrison and his colleagues collected a host of microscopic creatures off boat docks in Oahu, Hawaii, sifting out larvae of Philippine mantis shrimp (Gonodactylaceus falcatus) roughly the size of rice grains. They then glued the larvae onto toothpicks to record their punches in high-speed video. The researchers also captured a clutch of eggs from the species and raised the hatchlings for 28 days to see how the anatomy of their weaponry developed over time.
4-29-21 Mice on opposite North American coasts evolved the same way
On opposite sides of North America, house mice have strikingly similar adaptations to cold climates, and have independently evolved changes to genes that drive their similar behaviours and hardiness. House mice (Mus musculus domesticus) are native to Western Europe but have spread across the world thanks to their close association with humans. They arrived in the Americas more than 200 years ago and have since expanded into climates quite different from their original temperate home. To find out how these mice have adapted to new environmental conditions, Michael Nachman at the University of California, Berkeley, and his team collected 50 mice from locations in western North America ranging from Arizona in the US north to Alberta, Canada. The team analysed DNA from these wild mice and kept some to breed lab populations, comparing the western mice with those from a previous study on mice from eastern North America, ranging from Florida to New York. The mice were most closely related to those that shared their side of the continent, suggesting that mice in western and eastern North America had moved north independently after an initial spreading along a southern route, says Nachman. Yet the lab-reared mice from Alberta and New York were physically similar: both were bigger than southern mice and made larger nests, discouraging heat loss and providing insulation, respectively. Nachman was surprised the nest style was so clearly genetically encoded after just a few hundred generations. “Even at room temperature in a comfy lab with plenty of water and constant temperature and plenty of food, the mice from Canada build a bigger nest than the mice from Arizona,” he says. The western and eastern mice from cold climates shared changes in 16 genes, many involved with the regulation of body temperature.
4-29-21 Female black widow spider mates with and eats multiple males
A South American black widow spider starts biting, wrapping up and eating her willing partner before they have finished mating – and then mates with (and eats) another male. “Usually there are some advantages to the male for being eaten during mating, like longer copulations as well as decreased female receptivity to future males,” says Luciana Baruffaldi at the University of Toronto, Scarborough, Canada. “In this case, though, we don’t yet know how the male benefits from sexual cannibalism.” Despite a reputation for eating their mates, female widow spiders don’t always engage in such behaviour. However, scientists have identified three species in which widow females do often practise sexual cannibalism – eating a mate – during copulation. In two of the species – the redback spider (Latrodectus hasselti) and the brown widow spider (Latrodectus geometricus) – the males actually initiate the cannibalism by flipping themselves over to “offer” their abdomens to the female, Baruffaldi says. Curious about the behaviour of the third species – the mirabilis widow (Latrodectus mirabilis), native to South America – Baruffaldi and her colleague Maydianne Andrade collected dozens of juvenile spiders from the wild in Uruguay. They kept the arachnids in plastic cages at the Clemente Estable Institute of Biological Research in Montevideo, Uruguay, until they had moulted, meaning they had reached sexual maturity. The scientists then placed each female into a larger “mating arena” cage. Once each female had built a web, the researchers added a male to the arena. All 20 females accepted males that “courted” them by vibrating the webs. During copulation, 14 of the females cannibalised the males – which put up no resistance. The females bit the males’ legs and bound them up in silk while pulling the males’ abdomens up to their mouths to start eating them.
4-28-21 The Deep-Sea Podcast review: The mind-boggling mysteries of the deep
IT IS hard to imagine what the deep sea actually looks like. There is practically no light in this lowest layer of the ocean, which starts at a depth of 1800 metres and reaches almost 11,000 metres at its deepest-known point within the Mariana trench in the western Pacific Ocean. Hence nobody has actually seen the deep sea close up, meaning we typically rely on colourful depth maps created with acoustic techniques to visualise it. Furthermore, it is hard to make sense of the sheer scale of what lies underwater. The Pacific Ocean covers almost half the planet, for example. Due to its intangible nature, inaccurate analogies are often used to describe the deep sea. Alan Jamieson at the University of Newcastle, UK, is renowned for his journeys to the deepest parts of the ocean. He has teamed up with Thomas Linley, a deep-sea fish expert, to co-host a podcast that portrays the deep sea as it really is, but without removing any of the wonder. Every episode of The Deep-Sea Podcast delves into both important issues, such as whether deep-sea mining should be allowed to happen, and more light-hearted angles, such as a Halloween special on why humans seem to intrinsically fear the deep sea. The first instalment kicks off with one of Jamieson’s biggest bugbears: comparing the deep sea with the moon. It is often said that we know more about the moon’s surface than the deep sea, which he says is just plain wrong. “What other scientific discipline would start by saying how little they know about it?” Jamieson thinks the analogy is unfair, firstly because the moon isn’t that big. The surface area of the Atlantic Ocean, for example, is almost three times larger than that of the moon. And while crewed missions to the moon have pretty much stopped, those to the deep sea have never ceased and have even ramped up. “We know so much more about the deep sea now than we did five years ago or 10 years ago,” says Jamieson.
4-28-21 New species of 'pumpkin toadlet' poisonous frog found in Brazil
Pumpkin toadlets are poisonous frogs with brilliant orange skin that are small enough to fit on a thumbnail – and researchers have uncovered a new species of these vibrant amphibians. Ivan Nunes at São Paulo State University in Brazil and his colleagues suspected a local toadlet species (Brachycephalus ephippium) was more than it appeared to be. Unusually widespread for a pumpkin toadlet, the species was found throughout the south-eastern coastline of Brazil. The team suspected that the wide-ranging frogs were actually multiple species with smaller ranges. Nunes and his team collected wild toadlets from the Project Dacnis preserve near São Paulo, measuring and comparing the physical features of 276 frogs. The team also made 76 field surveys between October 2018 and September 2019 to study toadlet behaviour and habitat use. They also included museum specimens that were collected over a range of 200 kilometres. The team analysed DNA samples from 71 toadlets, and recorded the mating calls of several males to see how they compared with those of close relatives. Most pumpkin toadlet species are quite similar. They are exceptionally tiny frogs, among the smallest in the world at just over a centimetre long, and often have bright, tangerine skin that secretes a powerful neurotoxin. But the researchers found that a group of toadlets in the southern Mantiqueira mountains – a rugged, forested landscape with a diverse array of frogs found nowhere else – were distinct from their neighbours. They were smaller than B. ephippium, with faded black spots and DNA that differed by about 3 per cent. These differences warranted classification as a new species: B. rotenbergae. Like some other pumpkin toadlets, B. rotenbergae has bony plates on its skull and back that are fluorescent and glow through the skin under UV light. Nunes says it isn’t known what the fluorescent bones are for, but they might play a role in communication.
4-28-21 White noise could warn birds to avoid colliding with tall structures
Projecting white noise in the direction of oncoming birds could stop them from colliding with buildings or wind turbines. Birds keep their heads down to streamline their bodies as they fly, says John Swaddle at the College of William & Mary in Virginia. So, visual cues may not be enough to warn them of oncoming structures. That is why billions of birds around the world, particularly those that migrate long distances, die in collisions with manufactured structures each year. “Birds fly a bit like texting while driving,” says Swaddle. He and his team used white noise at around 70 decibels – about as loud as a vacuum cleaner – to try to get their attention when they are near tall structures. “These acoustic stimuli are like someone honking at them, making them more aware of their surroundings,” he says. The team used directional speakers around two communication towers along the Delmarva peninsula in Virginia, an area that millions of birds pass through going south during the North American autumn migration. The speakers were angled to only be heard by oncoming birds travelling from the north, and cameras recorded the flight paths of birds within a 500-metre radius. The team broadcast two sounds within the frequency range that most birds can hear, playing them for 30 minutes at a time with 30 minutes of silence between them over a total of 3 hours. One sound fell between 4 and 6 kilohertz, the other between 6 and 8 kilohertz. The team played these sounds for six days between September and November 2019. Compared with the periods of silence, bird activity decreased roughly 16 per cent around the towers when the 4-6 kilohertz sound was played, and 12 per cent while the sound at 6-8 kilohertz played. When birds flew within 100 metres of the tower, they were considered at risk for a collision. But the lower sound frequencies caused them to slow down more and divert their trajectories further around the tower. Swaddle says this may be because birds hear frequencies between 4 and 6 kilohertz more clearly.
4-28-21 Suzanne Simard interview: How I uncovered the hidden language of trees
First she discovered the wood wide web. Now Suzanne Simard has found that underground connections in a forest are like a brain that allows trees to form societies – and look out for their kin. Suzanne Simard was raised in the Monashee mountains in British Columbia, Canada. Her research, beginning with the discovery of the wood wide web, has transformed our understanding of forests. She is now a professor of forest ecology at the University of British Columbia. FEW scientists make much impact with their PhD thesis, but, in 1997, Suzanne Simard did just that. She had discovered that forest trees share and trade food via fungal networks that connect their roots. Her research on “the wood wide web” made the cover of Nature. What was then a challenge to orthodox ideas is today widely accepted. But Simard and her colleagues continue to challenge our preconceptions of how plants interact. Among other things, their research shows that the wood wide web is like a brain and can communicate information throughout the entire forest, that trees recognise their offspring and nurture them and that lessons learned from past experiences can be transmitted from old trees to young ones. Simard calls herself a “forest detective”. Her childhood was spent in the woods of British Columbia, Canada, where her family had made a living as foresters for generations. As a young woman, she joined the family profession, but soon realised that modern forestry practices were threatening the survival of the ecosystem she loved. She knew that, when logged with a lighter touch, forests can heal themselves, and she set out to discover how they are so naturally resilient. Along the way, her concern for the future of forests sparked an intense curiosity about what makes them tick. Simard is now a professor in the faculty of forestry at the University of British Columbia. Her new book, Finding the Mother Tree: Uncovering the wisdom and intelligence of the forest, tells how – like trees in a forest – her life and research are intricately intertwined.
4-28-21 Honeybees stress each other out by warning about minor parasites
European honeybees produce a warning pheromone when parasites infect their hive, yet the social stress this chemical causes might be more devastating than the parasites themselves. A one-celled fungus called Nosema ceranae can infect the guts of individual bees, causing a disease called nosemosis. Similar to tapeworm infections in humans, nosemosis apparently makes bees hungrier and reduces their resistance to pesticides and probably viruses, but it isn’t particularly fatal. Yet, nosemosis is one of the top reasons honeybee populations are declining. Christopher Mayack at Swarthmore College in Pennsylvania suspected this might have something to do with how the fungus affects the bees’ social structures. “Subtle changes in behaviour can be critical for the honeybee because it’s so highly social,” he says. “If their social harmony – really, their functioning as a group – gets disrupted, it can cause colony collapse, meaning complete dysfunction of the hive.” Bees, like most social insects, use pheromones to communicate. To learn how those pheromones – and hence social communication – alter during an N. ceranae infection, Mayack’s team vacuumed up 100 Apis mellifera forager bees from 30 different hives near Philadelphia, 18 of which were infected by this fungus. They then used a form of spectrometry to measure the bees’ pheromone production and their N. ceranae infestation rates. Compared with bees from uninfected hives, those from infected ones had much higher concentrations of a pheromone the insects produce when threatened by large invaders, like humans and bears. This so-called alert pheromone is commonly released when bees sting, or when they are crushed or killed. Bees also use it to mark flowers where they have already removed the nectar. The chemical seems to serve as an important call to action, whether to repel or to attract.
4-27-21 Male parasitic wasps can detect females inside an infected host fly
Males of a species of parasitic wasp can identify potential mates from chemicals they give off, even before the females have emerged from within their host fly. Jewel wasps (Nasonia vitripennis) are found across North America. Females deposit eggs inside the cocoon-like casings of developing flies, using their ovipositors to inject each fly with a venom that paralyses it. The developing wasps remain in the host as they mature from egg to adult, only eating their way out to mate. Males emerge first, hanging around on the hosts to wait for females to appear. “Males want to increase their mating success, so would benefit from finding hosts with females,” says Garima Prazapati at the Indian Institute of Science Education and Research (IISER) Mohali. It is possible for these wasps to up their chances. Males develop from unfertilised eggs and females from fertilised eggs, so some hosts hold all-male broods, while others house a mixture of males and females. Prazapati and her team collected jewel wasps from the wild and bred them. They isolated some females, keeping them from mating so their eggs would go on to create all-male broods. Next, they individually presented 26 male wasps with two Petri dishes: one holding a host containing male and female adult wasps, and one with a host containing only adult males. The researchers found that the males spent around four times longer on the host with the females inside. Analysing the chemical compositions of both hosts, the team found that the one containing female wasps had a higher abundance of nine cuticular hydrocarbons – compounds that cover the wasp exoskeleton – than the host with males inside. They then dipped adult wasps in a chemical solution that extracts these hydrocarbons and found that adult females also had a higher concentration of them than males.
4-27-21 Old tom cats have more mutations in their sperm like older human males
Genome sequencing of cats and their kittens has shown that the sperm of older tom cats has more mutations, just like that of older human males. This may show evidence of a universal phenomenon in male animals. “Our results suggest that this paternal age effect is general to mammals, and indeed anything that is producing sperm,” says Richard Wang at Indiana University in Bloomington. Each human is typically born with about 50 to 60 small mutations – such as a change in a single DNA letter – not found in the body tissues of their parents. These “de novo” mutations arise as sperm and eggs form. In people, 80 per cent of de novo mutations come from the sperm of the father, and older fathers pass on more than younger ones. “There are some studies that have linked the number of mutations and paternal age with autism, schizophrenia and a number of other neurodevelopmental disorders,” says Wang. There is some evidence this is also the case in other primates. To find out if it happens in other mammals, too, Wang and his colleagues sequenced the genomes of 11 parent-kitten trios. They found an average of 70 per cent of mutations came from the tom cats, and the older the tom, the more mutations it passed on to its kittens. The mutation rate per DNA letter per year is five times as high in cats as in people, the team found. However, because cats have offspring at a much younger age than people do, each kitten had only around 15 de novo mutations, says Wang. The reason the number of mutations increases with age is that sperm production requires continual cell division in the testes, which leads to an accumulation of small mutations. Egg production, by contrast, isn’t continual. However, because eggs remain stuck in the last stage of cell division, chromosomal abnormalities – very large-scale mutations – are much more likely to arise in eggs than sperm. This can lead to conditions such as Down’s syndrome.
4-26-21 This praying mantis inflates a strange pheromone gland to lure mates
Such an organ may be crucial for reproduction in a vast, dense rainforest. Praying mantises — with their angular features, huge eyes and centaur posture — often seem a bit alien. But researchers have recently found one mantis species that takes this otherworldly quality to the next level: Females of this species have an inflatable pheromone gland that protrudes from the back of the abdomen like a green, Y-shaped balloon. This odd organ is unlike anything seen in mantises before, researchers report online April 21 in the Journal of Orthoptera Research. In October 2017, herpetologist Frank Glaw was moving through the nighttime rainforest in Amazonian Peru at the Panguana research station, searching for amphibians and reptiles. His flashlight passed over a brown, leaf-mimicking mantis (Stenophylla lobivertex) in the tangle of vegetation, and he saw “maggotlike” structures protruding from its back. Those structures were quickly sucked back inside the insect after the light hit it, says Glaw, of the Bavarian State Collection of Zoology in Munich, Germany. Glaw was reminded of “parasites that eat the animal from the inside,” having seen such fatally parasitized insects before. With the help of Christian Schwarz, an entomologist at Ruhr-University Bochum in Germany, and observations of some female specimens in captivity, the team figured out that the mantis was no parasite-riddled vessel. When left undisturbed in total darkness, the female mantises extrude a pronged structure inflated with body fluids, roughly the hue and luster of polished jade. It appears to be a highly modified gland for producing pheromones — chemical signals that help female insects attract mates (SN: 5/13/15). Other mantises have simple, noninflatable glands that are located in the same section of abdomen as S. lobivertex’s bifurcated contraption.
4-26-21 The salmon you buy in the future may be farmed on land
In a series of indoor tanks 40 miles south west of Miami, Florida, five million fish are swimming in circles a very long way from home. The fish in question are Atlantic salmon, which are far more typically found in the cold waters of Norway's fjords or Scotland's lochs. As the species is not native to Florida, and would be unable to cope with the state's tropical heat, the water tanks are kept well chilled, and housed in a vast, air-conditioned and heavily insulated warehouse-like building. The facility, called the Bluehouse, opened its first phase last year, and intends to be the world's largest land-based fish farm. Targeting an initial production of 9,500 metric tonnes of fish per year, its owner - Atlantic Sapphire - plans to increase that to 222,000 tonnes by 2031, enough to provide 41% of current US annual salmon consumption, or a billion meals. The company is at the forefront of a growing movement in Europe, Asia and the US towards land-based, indoor aquaculture. But what could it mean for traditional sea-based salmon farms, and most importantly - what about the welfare of the fish? "When we started [exploring the concept] 10 years ago, people thought we were completely crazy," says Johan Andreassen, chief executive of Atlantic Sapphire, which is a Norwegian-owned business. "No-one was recognising that raising salmon on land would ever become financially viable, or even doable. Then the incumbent industry started to become more questioning. But they were waiting to see how the technology evolves. "And now with Atlantic Sapphire, we have proven that it's possible. So now it's a question of how competitive can this be, and how large can it become." The technology that enables Bluehouse to operate is not new, but using it on a commercial scale only became viable in the last few years. Called "recirculating aquaculture systems", or RAS for short, they control everything from the temperature, salinity and pH of the water, to its oxygen levels, artificial currents, lighting cycles, and removal of carbon dioxide and waste. The latter are filtered out, and treated water is reused. As it is a closed-loop system, the salmon are not exposed to seaborne diseases and parasites, so unlike sea-based farms, Atlantic Sapphire says its fish do not need to be treated with antibiotics or pesticides.
4-24-21 AI face analysis can tell if cows and pigs are excited or stressed
An AI system can detect nine emotional states in cattle and pigs by analysing their faces, and could lead to systems for monitoring and improving animal welfare on farms. At present, the focus is on reducing animals’ pain and distress, but automated systems could help boost positive states as well, says Suresh Neethirajan at Wageningen University & Research in the Netherlands. “There is a need to move away from just eliminating negative emotional states to providing positive states, such as playful behaviour.” Neethirajan collected thousands of images and videos of cattle and pigs from farms in Canada, the US and India and classified them based on cues known from previous research to reveal particular states or emotions. For instance, when the white of a cow’s eye is visible, it is usually a sign of excitement or stress. Forward-facing ears in a pig are a sign of alertness and sometimes aggression. Deep learning was used to detect the faces of animals in these images. The system was then trained to identify 13 facial actions, such as ear movements, that are associated with emotional states like stress, aggression, frustration, neutrality, relaxation and excitement. When tested on another set of images, the system matched the human classification around 86 per cent of the time. Neethirajan says it will take a couple of years to develop the system to a point where it could start to be used on farms. But he thinks continuous monitoring by cheap cameras hooked up to a cloud-based system could be far better than the occasional visits by welfare auditors that are required in some countries. According to Neethirajan, the ultimate aim is to be able to predict and prevent problem behaviours, such as tail biting in pigs, which can lead to serious infections.
4-23-21 Grasses pass genes from one species to another but we don’t know how
It’s freecycling, but for DNA. Grasses routinely pass genes from one plant to another, even if they belong to distantly related species. “We’ve shown that lateral gene transfer is a widespread process in grasses,” says Luke Dunning at the University of Sheffield in the UK. The finding adds to the evidence that DNA can be transferred from one complex organism to another, rather than only being inherited, and that this can benefit the recipient. Biologists have known for decades that single-celled organisms like bacteria can pass genes in this way, a process called lateral gene transfer or horizontal gene transfer. But as recently as 20 years ago, it was thought that this didn’t happen in organisms with more complex cells, known as eukaryotes – the group that includes all animals, plants and fungi. “People thought it was completely restricted to bacteria and didn’t happen in eukaryotes,” says Dunning. “It’s probably only been 10 to 15 years that that’s really shifted.” Nowadays many eukaryotic examples are known, such as a plant gene that has crossed into insects. Most studies of this phenomenon have focused on isolated examples: for example, in 2019 Dunning’s team showed that a grass called Alloteropsis semialata had 59 laterally transferred genes. To find out how widespread such gene transfer really is, Dunning’s team studied the genomes of 17 grass species, some of which have been evolving independently of one another for 50 million years. These included food crops like Asian rice, common wheat and foxtail millet. The team found that 13 of the 17 species carried laterally transferred genes – indicating widespread transfer. In total 170 genes had been transferred. “As more and more genomes of eukaryotes are sequenced, we’re seeing so many examples of horizontal gene transfer,” says Julia Van Etten at Rutgers University in New Jersey. She co-authored a 2020 study estimating that about 1 per cent of the genes in the single-celled eukaryotes called protists are the result of lateral gene transfer.
4-21-21 How to plant a fabulous front garden without losing your parking space
THE past year has made many people better appreciate the time they spend outside. But one kind of outdoor space has been on the decline in the UK for a few decades: front gardens. A major factor in this downturn is the growing number of people who pave over their front gardens to create parking spaces, as well as new homes being built this way. According to a 2015 survey by the Royal Horticultural Society (RHS), about 28 per cent of all UK houses were entirely paved or gravelled over at the front, a proportion that had tripled over the previous decade. Having more paved areas leads to flooding, as rain tends to quickly run off into street drainage systems rather than soaking into the earth, and less vegetation means less shelter for birds and less nectar for pollinating insects. All that concrete makes the place hot in summer, too. This greying of our streets is also concerning because a great deal of research has linked time spent in green spaces with better mental health. It is often hard to disentangle cause and effect in such studies, but a recent small, randomised trial in which plants were added to previously bare front gardens did show a modest reduction in people’s stress levels. From the participants’ comments, this may have been partly because they started chatting more to their neighbours as they tended their new plants, says Lauriane Suyin Chalmin-Pui at the University of Sheffield, UK, who led the research. To be fair, not everyone has the time (or a taste) for gardening, and for some households, a paved front area may be the only way they can park next to their home. But needing space for your car doesn’t mean all the greenery has to go. You could pave just two tracks for the car’s wheels and fill the surrounding areas with tough, low-growing plants like alpines.
4-21-21 Are humans the only animals that have unique fingerprints?
The soles of the feet of elephants develop unique patterns, much like human fingerprints. In fact, the carers at the HERD elephant rescue facility in Hoedspruit, South Africa, can identify individuals from their footprint patterns. If characteristics other than actual fingerprints are allowed, then the “fingerprint” idea can be broadened to include most species of animal, not just mammals. “Differences in wing patterns among insects can be as great as differences in fingerprints among primates” Differences in wing patterns among insects, for instance, can be as great as differences in fingerprints among primates. A few years ago, I noticed that a male comma butterfly would often guard a particular sunny glade, flying up to intercept any butterfly that crossed the area. This seemed to go on from early spring until autumn, so it couldn’t have always been the same comma – they don’t live long enough. I took a photograph of any male comma that I saw behaving in this way. Because of the differences in the wing patterns, it was possible to tell which was which. I found that photos I had taken on 30 occasions proved to be of 25 different butterflies. I recall seeing patterns similar to fingerprints on the pads at the tips of spider monkeys’ tails when I was on a trip to Costa Rica. These pads look like an oval of hairless black skin. Spider monkeys use their tails as a “fifth limb”, so I suspect the “fingerprint” structure helps the animals grip branches as they nimbly swing from tree to tree. The sole of the human foot is normally smooth and unmarked. Take up barefoot running, however, and you will find that it develops whorls and lines that look similar to those of fingertips.
4-21-21 Do animals cut the umbilical cord of newborns like humans do?
Humans aren’t the only animals to cut the umbilical cord – cats and dogs bite through them when their offspring are born. However, midwives do delay cord clamping and cutting if the infant is well to allow as much as possible of the blood supply from the placenta to reach them. Some parents choose not to cut the cord and have a “lotus birth”, where the placenta is placed in a bag with herbs and salt to help preserve it. It is then carried around with the baby until the cord dries and detaches naturally, usually within between three and 10 days. Almost all placental mammals do, in fact, intervene to sever the umbilical cord of their newborn. The exceptions are marine mammals and camels.Great apes usually bite through the cord in the process of eating the placenta. This combines cleanliness with returning nutrients to the birthing ape. The difference between humans and other mammals is that we use an instrument rather than our teeth.Precisely when during our evolution we began to take a clinical approach to a natural process is unclear. It is part of the bigger mystery of the nature and origin of disgust: why behaviour that is normal to animals evokes strong adverse psychological and physical responses in humans.
4-20-21 Redonda: The Caribbean island transformed into an eco haven
There are no resorts, no beaches, no amenities, and its contribution to the national GDP is practically zero. Yet the mile-long rocky isle of Redonda in the Caribbean Sea is deemed one of the most valuable spots in the region. Virtually untouched by humans for centuries, Antigua and Barbuda's lesser known third island has long been a key nesting site for migrating birds from across the world and home to wildlife found nowhere else on Earth. When environmentalists first touted the idea of entirely removing thousands of invasive black rats and a herd of feral goats threatening this wildlife, it seemed ambitious at best. Fast forward five years and uninhabited Redonda's once barren terrain is today a fertile eco haven, teeming with fresh new vegetation while populations of birds and endemic lizards have soared. Work began in 2016 but the project's real success was only revealed recently when conservationists made their first trip back in 18 months. "It was such a stark contrast from the first time I saw Redonda in 2016 when it was literally crumbling into the sea," she recalls. "As the helicopter got closer, I could see all these little circles of green and I realised they were brand new trees and shrubs. Not only has the vegetation recovered, it's thriving." Prior to their relocation, the long-horned goats introduced by early colonists 300 years ago had steadily eaten almost all of Redonda's plants to the extent they were starving to death. The rodents, which arrived with a 19th Century guano mining community, were preying on reptiles and eating rare birds' eggs. Removing both species was not without its challenges. The timid goats, unused to human contact, were corralled and flown by helicopter to farmers on the mainland keen to breed them for their drought-hardy genes. Eradicating the rats involved painstakingly laying bait in nooks and crannies across the landscape, flavoured with everything from peanut butter to chocolate "to make sure we got the picky ones", Ms Challenger explains. The bait was laced with a pesticide irresistible to rats but unpalatable to birds and reptiles. (Webmaster's comment: This is wonderful but the island is less than one square mile in area.)
4-19-21 Lucy the Human Chimp review: The ape that was raised like a human
So much is known, now, about our similarities to other primates, it is easy to forget that it was relatively recently that we were still establishing exactly where we humans ended – and they began. Through the 20th century, the study of chimpanzees in particular was a way to learn about ourselves: how we might fare in space, for example, and how we might communicate in the absence of a common tongue. Lucy The Human Chimp, a new television documentary from HBO and Channel 4, explores the meeting of those worlds through the story of one unique relationship: that between Lucy, a chimpanzee raised as a human, and Janis Carter, a graduate student hired to clean her cage. Through the late 1960s, Lucy was the subject of a high-profile study by psychologists Maurice and Jane Temerlin, ostensibly to explore the limits of nature versus nurture. The Temerlins brought Lucy up in their home more or less as though she was a human child, to the point of teaching her to dress herself, eat with silverware and even fix a gin and tonic. Primatologist Roger Fouts, whose success teaching a chimp named Washoe a form of American sign language was heavily publicised in 1970, likewise taught Lucy a vocabulary of 100 signs (though the extent of apes’ comprehension of signing remains disputed). Eventually the Temerlins came to regard the chimp as their daughter. Much has been made of Lucy’s story, including an episode of the acclaimed Radiolab podcast and the novel We Are All Completely Beside Ourselves (for which author Karen Joy Fowler said she drew from Maurice Temerlin’s “very disturbing” book Lucy: Growing Up Human). Lucy The Human Chimp, written and directed by Alex Parkinson, puts forward Carter, now 70, to share what happened next. Carter had been a 25-year-old psychology student within the University of Oklahoma’s chimp research project when, in 1976, she answered the Temerlins’ advertisement for a part-time carer for Lucy. After a frosty start – Carter remembers the chimp as “arrogant, and very condescending” about her poor comprehension of sign language – the two forged a close bond. But the adolescent chimp increasingly posed a threat to her human family, and was confined to a cage.
4-15-21 Heat overrides genes to make bearded dragon embryos change sex
Some lizards that begin developing as males will actually hatch as females if the egg is particularly warm – and now we know why. The heat triggers genes that override chromosomal sex determination. In the 1960s, French scientists discovered that reptiles in Senegal would hatch as females when temperatures rose much above about 30°C. Since then, researchers have noted that the sex of many reptiles and some fish actually depends entirely on the temperature during their development. In a few animals, like the central bearded dragons (Pogona vitticeps) of Australia, sex determination depends on both genetics and temperature. Males have two identical sex chromosomes – ZZ – and females have two different sex chromosomes – ZW. But male embryos will develop as females if the egg is warm enough. This means females may develop in one of two ways, but the mechanisms behind this phenomenon have eluded scientists for more than half a century. To explore the mystery, Sarah Whiteley at the University of Canberra in Australia and her colleagues ran genetic sequencing on unhatched bearded dragons incubated either at 28°C – cool enough for ZZ embryos to hatch as males – or at 36°C – warm enough for ZZ embryos to hatch as females. For the eggs at 36°C, the researchers found that ZW female embryos had “dramatically” different active genes during the major stages of sex development, compared with ZZ females, demonstrating there are two distinct sets of genes that can make a central bearded dragon female. In the ZZ females, the genes that “wanted” to code for male development were forcibly switched off, and those for female development were switched on. “The sex chromosomes in the dragon are… more recently developed – on an evolutionary timescale – compared to [human] sex chromosomes,” Whiteley says. “So sex reversal might be a relic of temperature sensitivity [alone].”
4-14-21 Wasps with no social life may find it harder to recognise others
Paper wasps that live alone don’t see as much development of a part of their brain that seems to be important for facial recognition. The discovery shows how vital the social environment can be to brain development, even in biologically simple animals like insects. Northern paper wasps (Polistes fuscatus) usually live in groups of around a dozen, though these sometimes comprise up to 100 individuals. Group members all share umbrella-shaped nests, often built beneath roof hangings. The wasps can live their entire adult lives alone, but they rarely do. Within their social groups, these insects recognise that all nest-mates share the same odour – but they also learn to identify individual group members by the unique colour patterns on their faces. “These wasps use facial recognition to basically know who’s who and maintain hierarchies, similar to what we see in many primate systems,” says Christopher Jernigan at Cornell University, New York. “It’s really incredible.” To understand how the paper wasps are able to recognise the unique colour patterns on other individuals’ faces, Jernigan and his colleagues gathered several cocoon-filled nests from the natural environment and placed them in clear plastic containers in their laboratory. As soon as the new adults chewed their way out of their silk cocoons – and could see for the first time – the researchers isolated some in a separate container, while leaving others in their nests to lead a social life. They provided all of the wasps with plenty of coloured paper, which stimulates their brains. When the wasps were between 58 and 71 days old, the researchers analysed their brains under a microscope, comparing them with each other and with the brains of newly hatched wasps. They found that, even though the wasps’ bodies didn’t grow after emerging from their cocoons, their brains had increased by about 13 per cent in size during those first two months of adulthood.
4-13-21 Discarded COVID-19 PPE such as masks can be deadly to wildlife
Animals around the world are eating or getting entangled in single-use masks and gloves. A Magellanic penguin in Brazil ingested a face mask. A hedgehog in England got itself entangled in a glove. An octopus off the coast of France was found seeking refuge under a mask. Wildlife and ecosystems around the world are suffering from the impact of discarded single-use COVID-19 protective gear, researchers warn March 22 in Animal Biology. Latex gloves and polypropylene masks which protect people from the coronavirus are exacerbating the plastic pollution problem when not disposed of properly and are causing wildlife deaths (SN:11/20/20). The study is the first global documentation of the impacts of COVID-19 litter on wildlife via entanglement, entrapment and ingestion (SN:12/15/20). In August 2020, volunteers cleaning canals in Leiden, Netherlands, chanced upon a perch — a type of freshwater fish — trapped inside a finger of a latex glove. The ensnared fish was the first recorded wildlife casualty caused by COVID-19 litter in the Netherlands. The find shocked two Leiden-based biologists — Auke-Florian Hiemstra and Liselotte Rambonnet — who wanted to know more about the extent of COVID-19 litter’s impact on wildlife. They embarked on an extensive search, online and in newspapers, to collate examples. They found 28 such instances from all around the world, pointing to a larger, global problem. The earliest reported victim was from April 2020: an American robin in Canada, which appears to have died after getting entangled in a face mask. Pets are at risk, too: In Philadelphia, a domestic cat ingested a glove, and a pet dog in Boston that had consumed a face mask. “Animals with plastic in their stomach could starve to death,” says Rambonnet, of Leiden University.
4-13-21 Saving the kelp forest that stars in My Octopus Teacher
The Bafta-winning Netflix documentary My Octopus Teacher focuses on a film-maker who befriends an octopus. But the unsung star of the show is actually the kelp forest off the coast of Cape Town that he dives in – one of the world’s richest ecosystems. The makers of the documentary are part of a campaign to preserve the underwater forest. BBC Africa Correspondent Andrew Harding went to meet them.
4-12-21 Corals’ hidden genetic diversity corresponds to distinct lifestyles
Understanding how corals behave could be key to preserving ocean biodiversity, experts say. Stony corals that build reefs have been hiding their diversity in plain sight. A genetic analysis of the most widespread reef coral in the Indo-Pacific revealed that rather than being a single species (Pachyseris speciosa), it was actually four distinct species of coral, researchers report April 2 in Current Biology. Coral reefs are the condominiums of ocean biodiversity, supporting more species per square meter than any other marine habitat. Understanding which coral species foster that biodiversity and how those corals behave is vital to taking care of them, especially as a warming climate threatens overall ocean biodiversity (SN: 5/6/20). “Just knowing what’s there is critical to tracking what we are losing,” says Rebecca Vega-Thurber, a marine microbiologist at Oregon State University in Corvallis, who was not involved in the new study. The results suggest other corals thought to be a single species may actually be much more diverse than researchers realized. Using a combination of scuba gear and remotely operated vehicles, marine biologist Pim Bongaerts of the California Academy of Sciences in San Francisco and colleagues sampled more than 1,400 P. speciosa corals from the ocean surface down to 80 meters. In the lab, the sampleslooked identical, and their internal structures were indistinguishable in scanning electron microscope images. Yet, their genomes — their full genetic instruction books — revealed the corals had diverged millions of years ago. That made sense for one of the species in the Red Sea’s Gulf of Aqaba, which was geographically separated from the others. But the other three newly identified species lived together on the same reefs in the waters off South Asia. If the corals were living together, why didn’t one overtake the other two, the team wondered.
4-12-21 The frequencies of a vibrating spider web have been made into music
Spiders are mostly blind, but their webs are sensitive to disturbances, which they detect with their legs. Now, scientists have created an audio-visual virtual reality take on this that converts a web’s vibrations to sounds we can hear, giving us an idea of what it might feel like to be a spider. “The spider web can be viewed as an extension of the body of the spider, in that it lives within it, but also uses it as a sensor,” says Markus Buehler at the Massachusetts Institute of Technology, who presented the work at a virtual meeting of the American Chemical Society. “When you go into the virtual reality world and you dive inside the web, being able to hear what’s going on allows you to understand what you see.” Because of differences in the length and tension of each strand of a spider’s web, they emit a different frequency when disturbed and can even be used to send out signals or communicate with other spiders when the web’s owner taps on the strands. Buehler’s team used laser imaging to create a 3D map of webs made by tropical tent-web spiders (Cyrtophora citricola). They identified each thread’s vibrating frequency through its size and elasticity, then converted those frequencies into ones that can be heard by humans. By piecing the visual and auditory layers together, users connect the sounds to the threads they see, mimicking a spider surveying its world, he says. The team made some artistic decisions, such as using a synthesiser with a harp-like sound. Threads that are closer to the listener or connected to many others sound louder than others. For Buehler, who has spent hours listening to the noises the virtual webs make, they no longer just sound dissonant, but begin to have identifiable structure. “We believe we have an accurate reflection of what the spider would ‘see’,” he says.
4-11-21 Saving green turtles... by cooling their eggs
The future of Australia's green turtles is under threat by climate change - but not how you might think. Warmer sand temperatures are leading to way more females being hatched than males. Ade Adepitan travels to breeding spot Heron Island, in the Great Barrier Reef, to find out how conservationists are helping to save the reptiles.
4-10-21 Female monkeys call to males when they see a predator approaching
When faced with a predator, female putty-nosed monkeys will call males to help protect them from the threat. Putty-nosed monkeys (Cercopithecus nictitans) live in the forests of West Africa in groups of one male with multiple females and their offspring. The male will tend to roam further from the group and leave females to forage for themselves, but the females and lone male will alert each other when predators are nearby. Communication in this species differs based on sex. Females produce a single “chirp” to alert others when any form of predator is nearby, while the lone males will use different calls based on the type of predator spotted: “pyow” calls for those on the ground, like leopards, and “hack” calls for predatory eagles. Claudia Stephan at the Wildlife Conservation Society, Republic of the Congo, wanted to see how female and male putty-nosed monkeys differ in their response to these calls during a predatory event when the male is roaming relatively far from the group. With her colleague Frederic Gnepa Mehon, also at the Wildlife Conservation Society, Stephan located 19 different groups of monkeys in Nouabalé-Ndoki National Park. For each group, the two researchers and their colleagues waited until the lone male was around 20 metres from the group. One volunteer, covered in a leopard print fabric to mimic a predator, then approached either the lone male or the group of females. If the “leopard” approached the lone male, he responded by making a “kek” call. Stephan says this call hadn’t been recorded during research on male putty-nosed monkeys in other regions, so could be a local dialect. But Stephan points out that earlier studies into alarm calls involved stationary leopard models, rather than a moving leopard model. “It could also be that moving danger on the ground elicit ‘kek’ calls, and any danger on the ground is ‘pyow’ calls,” she says.
4-9-21 Is Netflix's Seaspiracy film right about fishing damaging oceans?
A documentary about the fishing industry's impact on sea life and the oceans has caused a lot of debate. Many viewers have been saying they will no longer eat fish after watching the film, and expressed shock at the industrial scale of fishing. Others have argued it oversimplifies a complex issue - many communities depend on fishing for their livelihoods and for food, and are in fact practising sustainable catching methods. We looked into some of the main claims in the Seaspiracy film on Netflix. "If current fishing trends continue, we will see virtually empty oceans by the year 2048," says Ali Tabrizi, the film's director and narrator. The claim originally comes from a 2006 study - and the film refers to a New York Times article from that time, with the headline "Study Sees 'Global Collapse' of Fish Species". However, the study's lead author is doubtful about using its findings to come to conclusions today. "The 2006 paper is now 15 years old and most of the data in it is almost 20 years old," Prof Boris Worm, of Dalhousie University, told the BBC. "Since then, we have seen increasing efforts in many regions to rebuild depleted fish populations." There are plenty of examples of overfished stocks, the catching of unwanted fish, and habitat loss, as well as issues with pollution and climate change, says Prof Worm. But he points out there are also "countless efforts under way to repair the damage that has been done". Other experts have taken issue with the original claims in the 2006 study. There was an "unrealistic extrapolation way beyond the bounds of available data", says fisheries expert Michael Melnychuk, from the University of Washington. He says the study was not well received by the fisheries science community, and that this prediction has "persisted ever since". "Overfishing is certainly a problem in many regions of the world, but in regions where fisheries management regulations are based on scientific evidence and properly enforced, most fish stocks are doing well," says Dr Melnychuk. (Webmaster's comment: Killing a one ton shark just so we can eat a 10 pound fin is so wrong!)
4-9-21 Ocean noise: Study to measure the oceans' 'year of quiet'
Ocean scientists around the world are studying the "unique moment" of quiet created by the pandemic. The researchers have called their vast listening experiment: The year of the quiet ocean. "Lockdown slowed global shipping on a scale that would otherwise be impossible," explained Prof Peter Tyack from the University of St Andrews. The scientists plan to listen to the ocean soundscape before, during and after lockdown. They have identified 200 ocean hydrophones - underwater microphones that are already in place around the global ocean. "So the idea is to use those to measure the changes in noise and how they affect marine life - like calling whales or fish choruses," Prof Tyack said. "Just like people and cities may have noticed that, with much less traffic noise and human activity, you hear more birdsong or maybe see more wildlife in your own environment, we need ways to monitor that in the ocean." The aim is not only to measure how the pandemic briefly changed the ocean soundscape, but to take the opportunity to find out how decades of increasing ocean noise has affected marine life. Combined with other methods such as animal tagging, researchers hope this will reveal the extent to which noise in "the Anthropocene seas" affects life in the deep. "We've had such a big impact on the world's oceans - with pollution and climate change - but the thing about noise is that it's relatively easy to turn down the volume," said Prof Tyack. Prof Jennifer Miksis-Olds, an ocean acoustics expert from the University of New Hampshire said that the data from the year of the quiet ocean would provide insight into much more than just noise pollution. "There is so much we can learn from just listening to the sound of the ocean," she said. "One of my goals is to build a global ocean soundscape map, where you could see the sounds of shipping routes, see migration patterns of whales - from their song - and even learn about climate change from the sounds of icebergs calving."She added that listening to the ocean could help to "find the balance" between human activity and the natural processes in the ocean.
4-7-21 Dead eagles found across the US had rat poison in their blood
In a sample of eagles from across the US, rat poison was found in about 80 per cent of the birds. This widespread exposure to toxic chemicals could impair their health or even lead to death. “This really suggests that despite the best efforts to use these compounds wisely and minimise the opportunity for the raptor species to be exposed, they’re still somehow getting exposed,” says Mark Ruder at the University of Georgia. Between 2014 and 2018, Ruder and his team determined the cause of death for 303 golden eagles (Aquila chrysaetos) and bald eagles (Haliaeetus leucocephalus), which were sent to them from around the US. Some deaths couldn’t be explained, but the team determined that 4 per cent of the eagles died directly as a result of rat poison. They tested 133 of the birds for anticoagulant rodenticide, the most common rodenticide, which can also target opossums and beavers, and found that 82 per cent of the birds had it in their body. There was a high prevalence of what are known as second-generation anticoagulant rodenticides, which are highly toxic and can remain active for months after ingestion. These have been tightly regulated by the US Environmental Protection Agency since 2011 and are only available for commercial use. Eagles often scavenge, and rodents killed by the poison could become their food, although it still isn’t clear how exactly the eagles came into contact with it. It is also unclear whether the poison can affect reproduction or impair their health in other ways, says Ruder. “Such widespread exposure indicates that this issue is more than a localised phenomenon, and if there are widespread health impacts they may occur throughout the population,” says Garth Herring at the US Geological Survey, who wasn’t involved in the study.
4-7-21 Animal intelligence is so common, we must rethink our view of wildlife
Tests show that a growing number of animals have the flexible, problem-solving thinking we once thought of as our own. It's time to treat creatures with more respect. CALL it human curiosity, but it is natural to wonder what a pet is thinking, or to ponder, as philosophers and latterly consciousness researchers have, what it is like inside the mind of a bat or a bird or an octopus. We are inching closer to cracking the secrets of animal minds – and they aren’t what we expected. From Snowball the dancing cockatoo to sheep that can recognise celebrities, there are plenty of examples of animals doing clever things. Nevertheless, such antics could be mere party tricks, not a manifestation of something resembling the “general” intelligence that allows us to think our way through life’s challenges. In fact, many biologists have long assumed that animals don’t do much thinking at all, acting mostly on instinct instead. The idea was so ingrained that our curiosity didn’t extend to testing it – until recently. Obviously, you can’t put animals through human IQ tests. Nor would we necessarily want to, given that those tests provide only a limited and selective view of intelligence. But with a bit of ingenuity, you can devise a battery of tasks appropriate for a particular species. “We search for intelligent life elsewhere, but there is more on Earth than we imagined” A growing number of animals are passing such tests. These include creatures with tiny brains, such as mice, and others, like ravens, that don’t even have the brain structures we usually associate with intelligence. Clearly, humans aren’t alone in possessing a flexible, problem-solving sort of brain – or indeed attributes that build on that, such as culture. So we should be careful what traits we describe as uniquely human. But equally we should be careful not to anthropomorphise too much: no one can even be certain that other people think in the same way they do, let alone animals.
4-7-21 Human-like intelligence in animals is far more common than we thought
Stories of clever animals abound, from pigs playing video games to monkeys trading mobile phones – now tests reveal that they don't merely act on instinct but can think flexibly, like us. BARELY a month goes by without a new tale of animals behaving brightly. There are orangutans that craft umbrellas out of plant leaves, and chimps that employ stones as hammers with a technique that is uncannily similar to one seemingly used by our Stone Age ancestors. In Bali, long-tailed macaques steal from tourists and then exchange their swag for edible rewards – and they have learned to target high-value items as if they appreciate the basic principles of economics. Hyenas employ the art of deception, with low-status individuals sounding an alarm call that scares their rivals away from a tasty carcass. In one UK zoo, several parrots curse copiously, apparently to entertain visitors. Pigs have been taught to play video games, rats can learn the rules of hide-and-seek, and let’s not forget the golfing bees. Superficially, these behaviours certainly seem smart. But what do they really reveal about animal intelligence? The human mind is remarkable for its innovation and problem-solving across many different domains. Do other animals have the same sort of brains, or are their headline-grabbing antics no more than party tricks that require little complex reasoning? Scientists have begun devising elaborate tests to tackle this question. Like our own IQ tests, they allow researchers to assess the capacity of an animal’s mind, compare the mental abilities of different individuals and identify factors that lead to superior performance. The findings have been a revelation. They provide some fascinating insights into the anatomy of intelligence. And they may even shed light on the evolutionary origins of our own minds.
4-7-21 Yawning helps lions synchronize their groups’ movements
Subtle social cues may be embedded in a lion's lazy gape, new research suggests. Watch a group of lions yawn, and it may seem like nothing more than big, lazy cats acting sleepy, but new research suggests that these yawns may be subtly communicating some important social cues. Yawning is not only contagious among lions, but it appears to help the predators synchronize their movements, researchers report March 16 in Animal Behaviour. The discovery was partially made by chance, says Elisabetta Palagi, an ethologist at the University of Pisa in Italy. While studying play behavior in spotted hyenas in South Africa, she and colleagues often had the opportunity to watch lions (Panthera leo) at the same time. And she quickly noticed that lions yawn quite frequently, concentrating these yawns in short time periods. Yawning is ubiquitous among vertebrates, possibly boosting blood flow to the skull, cooling the brain and aiding alertness, especially when transitioning in and out of rest (SN: 9/8/15). Fish and reptiles will yawn, but more social vertebrates such as birds and mammals appear to have co-opted the behavior for purposes conducive to group living. In many species — like humans, monkeys, and even parakeets (SN: 6/1/15) — yawners can infect onlookers with their “yawn contagion,” leading onlookers to yawn shortly afterwards. Seeing the lions yawn reminded Palagi of her own work on contagious yawning in primates. Curious if the lions’ prodigious yawning was socially linked, Palagi and her team started recording videos of the big cats, analyzing when they were yawning and any behaviors around those times. Over four months in 2019, the researchers closely monitored 19 lions at the Greater Makalali Private Game Reserve, just west of Kruger National Park. The team found that lions that saw another member of the pride yawn were about 139 times as likely to yawn themselves within the next three minutes.
4-7-21 Tiny crystals give a plain fish twinkling, colorful dots under light
Puzzling fish twinkles from wide-banded hardyhead silversides might lead to ultra-tiny sensors. As light shines steadily on a silver slip of a fish, minuscule dots on the fish start flashing: blue, yellow, blue, yellow. The bodies “do not glow like luminous fish,” Masakazu Iwasaka, an interdisciplinary engineer at Hiroshima University in Japan has discovered. Instead of making their own light, it turns out that remarkable little photonic crystals in fish spots reflect certain wavelengths of light, alternating between blues and more greenish-yellows, he reports April 7 in Royal Society Open Science. Lots of biological materials have evolved tricks manipulating light. The iconic morpho blue butterfly doesn’t have a flake of blue pigment. It creates its dream-perfect sky blue with stacks of microscopic light-manipulating plates. So do blue-leaved begonias (SN: 11/28/16). Those fish reflectors are doing something similar in wide-banded hardyhead silversides (Atherinomorus lacunosus). “I found the flashing of a small spot by chance” while screening the dots no bigger than 7 to 10 micrometers across on fish backs, he says. Inside the reflective flash spots lie little platelets of the compound guanine that have grown in such a way that they can reflect colorful light depending on the angle. Guanine may sound familiar. It’s one of the four major coding units that pair up in storing DNA’s genetic information. What gives the fish guanine platelets particular abilities though remains a puzzle. Iwasaka suspects that inside a spot, platelets move in ways that change their apparent color and dazzle power. The blue-yellow light pulses only in living silversides. Dead fish just reflect white-white. Iwasaka hopes to create human-made counterparts to the fish reflectors. He proposes mimicking fishy structures for sensors far, far smaller than the period on a magazine page. Versions of little sparkling fish lights could fit into the world of micro-electromechanical systems (MEMS) to monitor conditions inside living tissues, responding to light or flashing themselves. In earlier work, he’s shown how guanine platelets can be manipulated in magnetic fields, suggesting that such sensors could be targeted and herded.
4-1-21 Ewes prefer to mate with submissive rams when given a choice
When female sheep get the choice, they would rather mate with a subordinate male than a dominant one. Dominant rams usually mate with ewes much more often than lower-ranking rams do. But they can literally run out of sperm from mating so much in a short period of time. And if they fathered all the lambs in a flock of sheep (Ovis aries), the group would have less genetic diversity, which can lead to malformations and inheritable diseases. So ewes, which generally mate with several males when they are in heat, could have their own strategy for preventing inbreeding, says Rodolfo Ungerfeld at the University of the Republic in Uruguay. To test this, he and his colleagues first ranked male hierarchy among eight rams by placing two of them with a ewe in heat to see which one stood closest to her for the longest time. Domestically raised sheep usually show dominance by subtle body language instead of violent fighting. Then they put the rams in pairs of one dominant and one subordinate male and tied them up at opposite corners of a large pen. They let the ewes loose in the pen, one at a time while they were in heat, until all 28 ewes had chosen between the rams. The researchers found that the ewes spent more time with the subordinate ram – on average it was three times longer, says Ungerfeld. Ewes also mated with the subordinate rams twice as often as the dominant ones. And a quarter of the ewes refused to approach the dominant ram at all. The findings make sense for a species in which sperm from different males compete for the female’s eggs in the reproductive tract, says Andrew McLean at the University of Melbourne in Australia. Ewes seeking out subordinate males to mate with ensure genetic diversity in their flock.