7-31-20 This parasitic plant consists of just flashy flowers and creepy suckers
With only four known species, Langsdorffia are thieves stripped down to their essentials. Doorknobs in skirts. Microphones in tutus. There are lots of ways to describe Langsdorffia flowers, but parasitic-plant specialist Chris Thorogood says they “absolutely look to me like deep-sea creatures.” Whatever you compare them to, the flowers are intricate, screaming red showpieces. That’s the total opposite of the unshowy rest of the plant. It has no leaves, just grayish, ropelike tissue that probes through soil and ranks in looks somewhere between blah and dried-up dog droppings. The mix of flashy sexual parts and super-simplified other structures makes sense for the plant kingdom’s extreme parasites, including the four known Langsdorffia species. Why grow a lot of greenery to feed yourself when you can steal what you need (SN: 8/23/16)? “They’re vampire plants,” says Thorogood, at the University of Oxford Botanic Garden & Arboretum. Langsdorffia’s underground rope sucks all the nutrition it needs from the roots of other plants, such as figs and mimosas. The burrowing freeloaders “challenge our notion of what plants even do,” he says. Spotting such marvels requires finding just the right wild spot. Neither Oxford nor any other botanic garden grows them, and Thorogood has never seen a live one, he lamented in a Langsdorffia profile in the May 2020 Plants People Planet. But his lucky coauthor, ecologist Jean Carlos Santos, has. The flowers of L. hypogea species pop out of the ground here and there in Central and South America, including Brazil’s savanna, the cerrado. “Imagine the visual impact,” says Santos, of Universidade Federal de Sergipe in São Cristóvão, Brazil. The flowers bloom during the dry season, erupting in loud reds from a thin carpet of other plants’ dead, brown leaves.
7-31-20 An immune system quirk may help anglerfish fuse with mates during sex
Deep-sea species lack genes involved in the body’s response against pathogens or foreign tissue. For deep-sea anglerfishes, sex resembles an organ transplant. It’s hard to find a partner in the dark depths, so a tiny male anglerfish fuses its tissues to a more massive female during mating, allowing the two to share not only sperm but even blood and skin (SN: 7/26/75). The creatures are the only animals known to mate in this parasitic way. How males and females fuse and avoid being rejected by each other’s immune systems — like a mismatched organ transplant — has been a mystery. Now, a study finds that anglerfish might not have to evade the immune system in the first place. Some species lack key genes involved in the body’s immune response, which may make fusion without deadly consequences possible, researchers report online July 30 in Science. In vertebrates, immune protection typically involves a bodily response called adaptive immunity that identifies and eliminates foreign threats like viruses. Immune cells, such as T cells, recognize fragments of invaders and present those pieces to other cells that then mount an attack. In another line of defense, proteins called antibodies bind to trespassers to mark them for removal by the immune system. In organ transplants, such responses can cause the new organ to fail. The deep-sea anglerfishes’ missing genes are involved in making those systems work. “When you look at [these fish], you scratch your head and think, ‘How is that possible?’” says Thomas Boehm, an immunologist at the Max Planck Institute of Immunobiology and Epigenetics in Freiburg, Germany. In humans, it’s often difficult to find the right match for organ transplants because of the adaptive immune system, “but these creatures seem to be doing it without knowing what’s going on.”
7-30-20 Deep-sea anglerfish fuse bodies to mate thanks to an odd immune system
Some species of anglerfish – the deep-sea predator that uses a luminous lure to attract prey – have a bizarre way of reproducing: they fuse with their mates. We now know how the fish can fuse tissues without triggering a potent immune response. They have a strange immune system. There are 168 known species of anglerfish, which are found at ocean depths beneath about 300 metres. Some species mate through a process known as sexual parasitism. Males, which are often less than 10 millimetres in length, attach to the body of the larger female. For some species of anglerfish, this attachment is temporary. In others, it is permanent: the skin tissues of the two fish fuse and eventually their circulatory systems connect, and the male becomes dependent on its mate for nutrients. In all other vertebrate species, the fusion of tissues would trigger a significant immune response, because an animal’s immune system attacks cells it recognises as foreign – the reason why people have to take immunosuppressive drugs after receiving an organ transplant. By analysing the DNA of 31 anglerfish specimens from 10 species, Thomas Boehm at the Max Planck Institute of Immunobiology and Epigenetics in Freiburg, Germany, and his colleagues found that fusing anglerfish species are missing key immune system genes. All other vertebrates have some form of adaptive immunity, in which white blood cells known as T-cells and B-cells protect the body by recognising foreign pathogens and producing specific antibodies against them. “Patients with defects in adaptive immunity are very poorly,” says Boehm. But the anglerfish seem to have traded adaptive immunity for reproductive success without severe consequences. Species with temporarily attaching males didn’t have functional aicda genes, which are needed for antibodies to mature. Permanently attaching species also had non-functioning rag genes, which are needed to assemble T-cell receptors.
7-30-20 Extinction: Quarter of UK mammals 'under threat'
A quarter of native mammals now at risk of extinction in the UK. This is according to the first Red List of UK mammals - a comprehensive review of the status of species, including wildcats, red squirrels and hedgehogs. The report's authors are calling for urgent action to prevent their loss. Prof Fiona Mathews from the Mammal Society told BBC News: "What this is clearly saying is that we have to act now - we can't continue on this same trajectory." It is the official list categorising species based on their conservation status - or how threatened they are. Compiled after a review of all the available evidence on mammal populations, threats to their survival and to their habitats, the list has to meet the internationally-agreed criteria for assessing the conservation status of different species."When we draw all the evidence together - about population size and how isolated and fragmented those populations are - we come up with this list of 11 of our 47 native species being threatened imminently," explained Prof Mathews. "And there are more species that are categorised as 'near threatened'. "That means that we need to keep an eye on these species, because while we don't yet have a red flag waving, they're still abundant enough to be able to turn things around." The Scottish wildcat and the greater mouse-eared bat are both listed in the most severely threatened category of Critically Endangered. And much more familiar animals - the red squirrel and the water vole - have been put in the second most urgent category of Endangered. Different animals face different threats. The now Critically Endangered Scottish wildcat population has not recovered from decades of persecution and, for the red squirrel, disease and competition from introduced grey squirrels has driven a steep decline. But something most conservation scientists agree on is that we we need to leave more wild space across the landscape for these species to recover.
7-29-20 A South American mouse is the world’s highest-dwelling mammal
A yellow-rumped leaf-eared mouse was found 6,739 meters (4.2 miles) above sea level atop a dormant volcano. A yellow-rumped leaf-eared mouse has shattered the world record as the highest-dwelling mammal yet documented. The mouse (Phyllotis xanthopygus rupestris) was found 6,739 meters, or 22,110 feet, above sea level on the summit of Volcán Llullaillaco, a dormant volcano on the border of Chile and Argentina. For comparison, Mount Everest is 8,848 meters high (29,029 feet). The record was previously held by the large-eared pika (Ochotona macrotis), reported at an altitude of 6,130 meters during a 1921 Mount Everest expedition. Birds have been found at even higher altitudes (SN: 2/13/14). That mammals can live at these heights is astonishing, considering there’s only about 44 percent of the oxygen available at sea level. “It’s very difficult to sustain any kind of physical activity, or mental activity for that matter,” says Jay Storz, an evolutionary biologist at the University of Nebraska–Lincoln. The temperature is also rarely above freezing and can drop as low as –60° Celsius. Storz and colleagues captured several yellow-rumped leaf-eared mice, including the summit-topping one, plus mice from three other species from a range of high altitudes, the team reports July 16 in Proceedings of the National Academy of Sciences. Next, the team plans to look for genetic changes that might have equipped these animals to survive at high elevations. Surprisingly, another yellow-rumped leaf-eared mouse was found at sea level, indicating that this species has the broadest altitude distribution of any mammal, in addition to the altitude record. “It’s so amazing that they’re up there,” says Graham Scott, a physiologist at McMaster University in Hamilton, Canada who was not involved in the study. Understanding how these and other animals survive under low-oxygen conditions could provide insight into how humans could overcome diseases that cause reduced oxygen levels, he says.
7-28-20 Endangered tigers have made a remarkable comeback in five countries
Tiger numbers are increasing across five of the countries where the endangered big cat is found, conservationists have said. The number of wild tigers is on the increase in Bhutan, China, India, Nepal and Russia, a decade on from the launch of an ambitious scheme to double the population of the species. The TX2 initiative was launched in 2010 when it was estimated that wild populations of the cat were at a historic low, with as few as 3200 animals remaining across the 13 countries where they are found. The scheme aims to double the number of tigers in the wild by 2022. In India, the number of wild tigers in 2018 is estimated to have been at between 2600 and 3350 animals – around three-quarters of the world’s population, and more than double the number in 2006. Nepal’s population of tigers had nearly doubled by 2018, up from 121 individuals in 2009 to 235. The population in Nepal’s Bardiya National Park alone has increased from just 18 tigers in 2008 to 87 in 2018, conservation charity WWF said. In Russia, Amur tiger numbers have increased by 15 per cent in the past 10 years to around 540 animals, and in Bhutan’s Royal Manas National Park, the population rose from only 10 tigers a decade ago to 22 in 2019. In 2010, China had no more than 20 wild tigers, most of which had crossed the border from Russia. The country recorded a landmark moment in 2014 when camera traps captured footage of a tigress and her cubs in Wangqing Nature Reserve in Jilin province, indicating that tigers were breeding in China again and dispersing into new areas. Becci May at WWF UK, said: “Ten years ago, tigers were in such a perilous state that there was a very real risk of them becoming extinct in the wild. From that population low in 2010, they are finally making a remarkable comeback in much of South Asia, Russia and China, thanks to coordinated and concerted conservation efforts in these countries.”
7-28-20 Australia's fires 'killed or harmed three billion animals'
Nearly three billion animals were killed or displaced during Australia's devastating bushfires of the past year, scientists say. The findings meant it was one of "worst wildlife disasters in modern history", said the World Wide Fund for Nature (WWF), which commissioned the report. Mega blazes swept across every Australian state last summer, scorching bush and killing at least 33 people. Mammals, reptiles, birds and frogs died in the flames or from loss of habitat. During the peak of the crisis in January, scientists had estimated that 1.25 billion animals had been killed in New South Wales and Victoria alone. But the new estimate takes in a larger area. About 11.46 million hectares - an area comparable to England - was scorched from September to February. "When you think about nearly three billion native animals being in the path of the fires, it is absolutely huge - it's a difficult number to comprehend," said Prof Chris Dickman, who oversaw the project by 10 scientists from Australian universities. He said they could not yet state an exact death toll, but noted the chances of animals escaping the blazes and surviving were "probably not that great" due to a lack of food and shelter. The numbers were based on population counts and estimates of animal density before the disaster. Limitations on data meant that some groups - such as invertebrates, fish and turtles - were not included in the estimates. In February, the Australian government identified 113 animal species which needed "urgent help" after the bushfires. Almost all on the list had lost at least 30% of their habitat in temperate forests and grasslands of Australia's south and east. Koalas and wallabies - as well as bird, fish and frog species - were among those needing the most help, said experts. The government pledged A$50m (£27m; $35m) to wildlife and habitat recovery, but environmentalists have called on Australia to strengthen its conservation laws. Australia is holding a royal commission inquiry into the fires, which is due to report findings in October.
7-27-20 A wasp was caught on camera attacking and killing a baby bird
Some wasps scavenge carrion, but reports of attacks on live birds are rare. A wasp’s bites may be as bad as its sting. A paper wasp (Agelaia pallipes) has been caught on camera attacking and killing a baby bird in its nest, researchers report July 13 in Ethology. The video shows the wasp landing on the 4-day-old lined seedeater’s head while its parents were away. The wasp repeatedly bit the nestling and tore at its flesh, leaving it bloodied and mortally wounded. Other young birds in the same area of Florestal, Brazil, had similar injuries, suggesting that such attacks may be more common than expected. We tend to think that birds prey on wasps, but the opposite can happen, says Thiago Moretti, a forensic entomologist in Campinas, Brazil, who was not involved with the work. Wasps are known to visit birds’ nests to get a protein-rich snack of parasites, such as mites or fleas, that dwell on the birds, he says. The insects also scavenge carrion. But they rarely attack living vertebrates, he says (SN: 6/21/19). With a vulnerable bird, “it is a matter of opportunity.” Researchers caught the killing while filming nests to study the parental behavior of lined seedeaters (Sporophila lineola). “It was totally unexpected,” says Sjoerd Frankhuizen, a zoologist at Wageningen University & Research in the Netherlands. Upon finding the wounded nestling, Frankhuizen and his team suspected a reptile, larger bird or possibly ants, since the body was left behind. “We really had no idea that it would be a wasp,” he says. A. pallipes lives in big colonies, so you wouldn’t expect one to take down a nestling on its own, Frankhuizen says. During this encounter, thought, the lone attacker made 17 visits during the roughly hour and 40 minutes of video, possibly making multiple trips to carry bits of the bird to its own nest, he says.
7-26-20 Why are scientists creating genetically modified mosquitoes?
Creating these "Trojan horse" bugs could save human lives. But is it moral? Scientists plan to release altered mosquitoes designed to sabotage the species' ability to reproduce. Is this safe? Here's everything you need to know:
- Who's doing this? The federal Environmental Protection Agency has approved a plan by a British biotech company called Oxitec to release about 1 billion genetically modified (GM) mosquitoes in the Florida Keys and, next year, Texas. The mosquitoes (code-named OX5034) will only be male — the gender that does not bite humans — and will carry a new gene that will be passed on to their female offspring and cause them to die while they're still larvae.
- How does this technology work? Scientists first genetically modified an animal — a mouse — in 1974. But the process remained cumbersome and slow until the development of the CRISPR technique and other "gene-editing" technology this decade.
- Where do the plans stand? n May, the EPA greenlighted Oxitec's plans for both Florida and Texas, issuing the company an experimental use permit. Florida state authorities followed suit with their own approval.
- What could go wrong? Some geneticists, including Dr. Ricarda Steinbrecher of EcoNexus, a public-interest research organization, have raised alarms that Oxitec's altered mosquitoes haven't been adequately studied. The researcher said "the underlying mechanism(s) leading to cell death" in the larvae aren't "fully understood" and thus can't yield "precise and predictable results.
- What's the upside? Some see world-changing possibilities. Florida witnessed its first mosquito-to-human transmission of the Zika virus (which causes serious birth defects) in 2016, and West Nile is a perennial problem.
- Oxitec's modified moths: South Florida and Texas aren't the only places that Oxitec is testing its genetically modified insects. Earlier this year, Cornell University scientists announced the results of a project they had conducted with the company involving its genetically modified diamondback moths, or Plutella xylostella.
7-24-20 Coronavirus: Vietnam bans wildlife trade over pandemic risk
Vietnam has banned the import of wildlife and wildlife products to reduce the risk of new pandemics. The move also bans wildlife markets for such items, including online sales. Vietnam has previously been accused of turning a blind eye to the sale of products such as pangolin scales and rhino horns often used in traditional medicine. Scientists have long warned that the wildlife trade can be an incubator for disease. The origins of the current Covid-19 pandemic are thought to lie in the wildlife trade, with the disease emerging in bats and jumping to people via another, as yet unidentified, species, which could include rats, civets and pangolins. "The prime minister orders the suspension of imports of wildlife - dead or alive - their eggs... parts or derivatives," said the order released on Thursday on the Vietnamese government website. "All citizens, especially officials... must not participate in illegal poaching, buying, selling, transporting... of illegal wildlife." The country will also "resolutely eliminate market and trading sites which trade wildlife illegally", the order said. Conservationists welcomed the move. "Vietnam is to be congratulated for recognising that Covid-19 and other pandemics are linked to the wildlife trade," said Steven Galster, chairman of the anti-trafficking group Freeland. "This trade must be banned as a matter of international and public health security," he added. However, one group said the ban did not go far enough. "The wildlife consumption ban mentioned in the directive is insufficient as some uses of wildlife such as medicinal use or wild animals being kept as pets are not covered," said Nguyen Van Thai, director of Save Vietnam's Wildlife. In February, a dozen conservation groups sent a joint letter urging the government to "identify and close markets and other locations where illegal wildlife is on sale", Reuters news agency reports.
7-24-20 Spiderwebs gather DNA that can help us monitor insects in forests
Spiders may build their webs to catch prey, but trials in Slovenian forests have shown they can also moonlight as a way for humans to monitor the biodiversity of ecosystems. Recent years have seen a growing interest in detecting species by collecting the fragments of DNA they shed in an environment, an approach that is often less invasive and quicker than traditional surveying with nets, trays and other equipment. Matja? Gregoric at the Slovenian Academy of Sciences and Arts turned to an unusual tool to collect such environmental DNA: the orb webs of garden spiders (Araneus diadematus) and sheet webs of common hammock-weaving spiders (Linyphia triangularis). The webs act as a passive filter for the air, capturing DNA from insects, fungi and bacteria – and providing an elegant alternative to the air filtering machines ecologists use, which need to be powered by heavy generators. “The results are fantastic, much more than I hoped for. From 25 webs, I found [DNA from] 50 families of animals, from nematodes to butterflies, moths, wasps, bees, beetles and flies, everything. The richness of information surprised us a lot,” says Gregoric. He and his colleagues got the idea from a 2015 trial in the highly controlled environment of a zoo, but Gregoric says their research is the first proof of concept in the wild. The approach could complement traditional ways of surveying pollinators, which are suffering major declines, or be used for the early detection of pests and invasive species. The use of environmental DNA to monitor ecosystems is growing, with the technique being deployed by regulators in English rivers and lakes. The approach doesn’t require years of taxonomical knowledge to identify species, which instead have their DNA matched against databases. “You don’t have to be a spider expert to use spider webs,” says Gregoric.
7-23-20 Night lights cause severe loss of sleep for pigeons and magpies
City lights could have a serious impact on the sleep patterns of birds, according to the first study to look at neurological activity in animals thought to be affected by light pollution. Researchers used miniature sensors to record brain activity in pigeons and magpies on three nights in an indoor aviary. On the second night, the birds were exposed to lights with a similar intensity to street lights. The study looked at both white light and amber light, the latter of which may have less of an effect on sleep patterns, previous research has suggested. Both rapid eye movement (REM) sleep and non-REM sleep were affected by the lighting. Magpies were more affected by white light than amber light, losing 76 per cent of their non-REM sleep, while pigeons lost about 4 hours of sleep in total, regardless of the type of light. In the wild, birds might choose to avoid sleeping under lights, but some wild pigeons and magpies have been found to sleep in conditions like those in the study, says Farley Connelly at the University of Melbourne and La Trobe University, Australia, who co-authored the study. “We have even seen pigeons roosting directly opposite bright white security lights,” he says. The consequences of disturbed sleep for the birds will depend on whether they can get used to light at night, says co-author Anne Aulsebrook, also at the University of Melbourne and La Trobe University. “Sleep loss can cause problems for behaviour, health and development, so if birds can’t adapt or tolerate light at night, they might suffer poorer health, produce fewer offspring or have to find new habitats,” she says.
7-23-20 Conservation: Reef sharks are in major decline worldwide
Sharks are rarely seen at almost one in five of the world's coral reefs, a major study has found. The crash in shark numbers, caused largely by over-fishing, could have dire consequences for corals struggling to survive in a changing climate, researchers have said. Sharks are top predators, playing a key role in marine ecosystems. They did best in places where shark fishing was controlled, or where marine sanctuaries had been created. Dr Mike Heithaus of Florida International University, US, said: "At a time when corals are struggling to survive in a changing climate, losing reef sharks could have dire long-term consequences for entire reef systems." The research, published in the journal Nature, and part of the Global FinPrint study, reveals widespread loss of reef sharks across much of the world's tropical oceans. Species such as grey reef sharks, blacktip reef sharks, and Caribbean reef sharks were often missing from reefs where they would historically have been found. To carry out the study, underwater cameras were fitted on 371 reefs across 58 countries from the Central Pacific to the Bahamas. Bait was attached to a pole at the front of the cameras to attract any nearby sharks. Almost no sharks were detected on any of the 69 reefs of six nations: the Dominican Republic, the French West Indies, Kenya, Vietnam, the Windward Dutch Antilles and Qatar. But the researchers said there were grounds for hope. By regulating how sharks are fished, populations have a chance to recover. Dr Aaron MacNeil of Dalhousie University, Canada, said, "From restricting certain gear types and setting catch limits, to national-scale bans on catches and trade - we now have a clear picture of what can be done to limit catches of reef sharks throughout the tropics." Many of the world's shark species are threatened by over-fishing, often for their meat and fins, or because they are unintentionally trapped in fishing gear. Estimates suggest that 100 million sharks are killed by people each year.
7-22-20 Hungry foxes have been raiding our bins for thousands of years
We shouldn’t be surprised by how well foxes can survive by scavenging from our food leftovers – it is a behaviour that is tens of thousands of years old. The ancestors of today’s foxes began living on humans’ food remains about 42,000 years ago, according to an analysis of animal bones found in Germany. “It’s the same as how they behave today in towns,” says Chris Baumann at the University of Tübingen in Germany. Today, red foxes (Vulpes vulpes) and Arctic foxes (Vulpes lagopus) prey on small rodents in the wild as well as scavenging from the carcasses of animals, often those killed by large predators like bears and wolves. But the closer they live to towns and villages, the more their diet is made up of people’s food leftovers. “They’re very flexible,” says Baumann. He and his team analysed animal bones, including those of foxes, bears and wolves, found at sites in south-west Germany. The sites had been dated to three time periods: older than 42,000 years ago, when Neanderthals were the only humans living in the region, and two later periods when modern humans had moved in, lasting until 30,000 years ago. By measuring the different isotopes of carbon and nitrogen in the bones, the team could work out what the animals had been eating. In the oldest period studied, foxes had eaten a mixture of animals, and these were likely to have been killed by bears, wolves and lions. But after around 42,000 years ago, some of the foxes had switched to eating mainly reindeer. None of the other carnivores were mostly eating reindeer, so the foxes couldn’t have been scavenging from the kills of wolves, for instance. While humans at the time ate a range of animals, including mammoths, “in cave sites, we find a lot of reindeer bones, because they are easy to transport as whole bodies to the caves”, says Baumann. “And if humans butchered them there, it would have produced food waste.”
7-22-20 Lockdown is a unique chance to see how human activity affects wildlife
Rewilding efforts have been emboldened by the sudden cessation of everyday life during the coronavirus pandemic. Scientists are seizing the opportunity to learn how best to support our wildlife, says Graham Lawton. WHEN I sat down at my kitchen table at the tail end of winter to write my first column under lockdown, I didn’t think I would still be there come midsummer. That piece was about the health benefits of contact with nature and how to get them in a locked-down world. I was reminded of this last week during a bike ride with my wife through the still-quiet streets of central London. We swung through St James’s Park and stopped at the lake to admire the pelicans. The sun was shining, the water was clear and the big, ungainly birds were splendidly alien. It was a painful reminder of our decision to cancel a planned holiday to Greece, and with it the hope of seeing wild Dalmatian pelicans. Thankfully, the country I am stuck in is becoming increasingly exotic. The pandemic has done little to slow Britain’s accelerating rewilding movement. In the past few months, we have heard that European bison will soon be coming to Kent, that pine martens are making a comeback in England and that a pair of white storks at the Knepp Estate in West Sussex have successfully raised chicks – the first wild storks to breed in Britain for more than 500 years. Two major rewilding projects have also been announced during lockdown. Solar power entrepreneur Jeremy Leggett has bought a 500-hectare estate in the Highlands of Scotland to restore nature there, and farmers in East Anglia are planning to turn over 250,000 hectares of intensively farmed agricultural land that could one day support lynx, beavers and, yes, pelicans. Rewilding is largely a matter of humans getting out of the way and letting nature take charge. That, of course, has been happening in spades of late due to the sudden suspension of life as we know it – a period that a group of biologists has proposed calling the anthropause.
7-21-20 How Yellowstone wolves got their own Ancestry.com page
Since reintroduction, 25 years of passionate watching has chronicled life, death and puppies. Wildlife ecologist Jim Halfpenny was standing by the stone arch at the north entrance to Yellowstone National Park on January 12, 1995, when horse trailers eased through carrying the first wild gray wolves to enter the park in about 60 years. Delivered from Canada, these wolves were the beginning of a historic attempt to complete and restore the park’s ecosystem by reintroducing a species wiped out decades before (SN: 3/17/19). He remembers that the schoolchildren who had gathered were disappointed to see only trailers, with not even a glimpse of fur. However, Halfpenny and the other elated adults “were up there howling our heads off,” he says. Not everyone in the region was pro-wolf, though. Seven of the 41 genetic founders of Yellowstone’s Canis lupus population introduced that year and the next ended up being shot illegally. Deep cultural memory entangles wolves and wilderness in all their terror and majesty. In Europe’s bouts of bubonic plague, “there would be people standing on the fortress walls watching their parents being eaten by wolves because they had died and been thrown out,” Halfpenny says. Yet wolves also tug heartstrings as cousins of humankind’s beloved dogs. In surveys of the Yellowstone’s winter visitors, “the No. 1 thing they want to see is the wolf,” he says. “In the summer, it’s bear, then the wolf.” At the time of the reintroduction, Halfpenny was teaching about wolves and other wildlife for his own company, A Naturalist’s World, while still working with the University of Colorado’s Institute of Arctic and Alpine Research in Boulder. From the beginning, as he recorded the introduced wolves’ pairings, puppies and the rise and fall of packs, he wished Yellowstone visitors and other passionate wolf fans also could follow the story lines. Then it hit him: “People have Ancestry.” The genealogy website Ancestry.com, he thought, could introduce wolves as the first nonhuman section.
7-20-20 Red kite 30-year Chilterns project a 'conservation success'
The reintroduction of red kites to an area of outstanding natural beauty 30 years ago has been a "true conservation success story", an expert has said. Numbers of kites had declined over a 200-year period and by the 1980s they were one of only three globally-threatened species in the UK. Thirteen young birds were brought over from Spain and released in the Chiltern Hills in July 1990. They are now "thriving", with an estimated 1,800 UK breeding pairs. The red kite is one of Britain's most distinctive birds of prey, known for its reddish-brown body, angled wings, forked tail, and "mewing" call. They used to breed across much of the UK, but persecution over the years saw numbers fall as they increasingly became a target for egg collectors. At one point there were just a few breeding pairs in central Wales. The Chilterns area was chosen as it met the criteria set out by the International Union for Conservation of Nature (IUCN) for the project. The Chiltern Hills were designated an Area of Outstanding Natural Beauty (AONB) in 1965 and stretch from Goring in Oxfordshire, through Buckinghamshire and Bedfordshire, to Hitchin in Hertfordshire. More birds were introduced and by 1996, at least 37 pairs had bred in southern England. Red kites can now be seen in most English counties with an estimated 10,000 birds in the UK, including 1,800 breeding pairs. Tony Juniper, chair of Natural England, said these "most majestic birds of prey" had been "persecuted to near-extinction", but the "pioneering reintroduction programme in the Chilterns stands out as a true conservation success story". While the "majestic" red kites have been targeted by hunters and egg thieves, they have also had some bad press themselves as numbers have increased. Reports including the birds swooping on school children as they ate their lunches, and "sweeping up chickens", prompting calls for people to stop feeding them as there was plenty of wild food for them to eat.
7-17-20 How some superblack fish disappear into the darkness of the deep sea
A layer of pigment-containing structures just below the skin’s surface traps nearly all light. In the depths of the ocean, it might take more than a little light to illuminate some of the planet’s darkest fish. Some deep-sea fish have ultrablack skin capable of soaking up almost all light that hits it, making the fish nearly invisible. That camouflage is the result of a layer of densely packed pigment-containing structures just below the skin’s surface, researchers report online July 16 in Current Biology. The skin may hide the fish from predators, or prey, and might inspire new designs for ultrablack materials used in telescopes or fabric. Although little light reaches the deep sea, bioluminescent organisms can brighten the inky darkness. For creatures trying to swim undetected, living in these depths is “like trying to play hide and seek on a football field,” says Karen Osborn, a marine biologist at the Smithsonian National Museum of Natural History in Washington, D.C. “There’s nowhere to hide.” Enter superblack skin. Osborn and her colleagues captured 18 species of ultrablack fish from up to 2,000 meters deep in Monterey Bay off California and in the Gulf of Mexico. The team then measured how much light reflected off of the fish. The researchers also examined skin from nine species using electron microscopy and calculated how structures in the skin might absorb light. The skin has a layer of closely packed, circular, melanin-containing structures called melanosomes that can absorb up to 99.95 percent of light with wavelengths similar to ambient sunlight in the ocean or light from bioluminescent animals. The melanosomes’ size, shape and arrangement may help direct light that isn’t absorbed by an individual melanosome to others in the layer, trapping even more light. Other dark-colored fish tend to have unpigmented gaps between melanosomes, which leads to more light being reflected and a more visible fish.
7-17-20 Scientists shed light on how the blackest fish in the sea 'disappear'
An ocean mystery - how the blackest fish in the deep sea are so extremely black - has been solved in a study that began with a very bad photograph. "I couldn't get a good shot - just fish silhouettes," said Dr Karen Osborn from the Smithsonian Institution. Her detailed study of the animal's "ultra-black" skin revealed that it traps light. While it makes the animals difficult to photograph, marine scientists say it provides the ultimate camouflage. There is, Dr Osborn explained, nowhere to hide from predators in the deep ocean, so this "ultra-blackness" renders creatures almost invisible. The discovery, described in the journal Current Biology, could provide the basis for new ultra-black materials, such as coatings for the interior of telescopes or cameras. Several ultra-black species, according to the research, appear independently to have evolved the exact same trick. "The particles of pigment in their skin are just the right size and shape to side-scatter any light they don't absorb," Dr Osborn, from the Smithsonian's National Museum of Natural History in Washington DC, explained. These pigment particles are arranged in a densely-packed, thin layer. "So instead of bouncing the light back out, they scatter it back into the layer - it's a light trap." It was Dr Osborn's frustrated efforts to take good photographs of the deep-sea species she was studying that inspired her and her colleagues to take a much closer - microscopic-scale - look. "Every picture I took was really bad - it was so frustrating," she told BBC News. "[Then] I noticed they had really strange skin - they're so black, they suck up all the light." This light-trapping skin, the researchers say, is the ultimate in deep-sea camouflage - where there is very little light, but where other species - including predators - make their own bioluminescent light. "You don't know where that light is going to come from," Dr Osborn explained. "So living in the deep sea is like playing hide and seek on a football field - your best shot is to turn green and lay down as flat as you can."
7-16-20 Sea turtles sometimes get really lost in the ocean on the way home
Sea turtles are famed for their ability to navigate across open oceans. Now we have a better idea of how they do it, thanks to a GPS tracking study that reveals they often make a lot of mistakes along the way. “We were impressed that they are able to find small islands,” says Nicole Esteban at Swansea University in the UK. “But their navigation is crude.” Green sea turtles (Chelonia mydas) spend most of their lives in one area, feeding on seagrass in shallow waters. Every few years they migrate to breeding areas that can be up to thousands of kilometres away, spending a few months there before returning. During migrations in 2013, 2015, 2017 and 2018, Esteban and colleagues put GPS trackers on a total of 33 female green sea turtles after they had nested on the island of Diego Garcia in the Indian Ocean. As the turtles cannot feed in the open ocean, the team think their aim would be to go straight to their home feeding area. Few managed it. Unsurprisingly, turtles that feed off the coast of Africa were the mostly likely to travel fairly directly to their target, as once they reach the coast they just have to swim a short distance north or south to find their feeding ground. But turtles returning to remote atolls and islands often missed their target and ended up swimming up to four times further than they needed to. For instance, one individual that ended up at an atoll near Providence island initially passed it 200 kilometres to the south on 5 November 2017. She continued westwards for another 500 km before seeming to realise her mistake and wiggling around as if searching. The turtle returned eastwards – passing other good feeding grounds without stopping along the way – and finally reached the atoll on 31 December 2017. She travelled 4619 km overall when the straight-line distance was just 2240 km.
7-14-20 The ‘ratpocalypse’ isn’t nigh, according to service call data
Rat-related calls in New York City went down during COVID-19 lockdowns. During March and April 2020, as New York City restaurants went dark and their dumpsters stood empty as a result of COVID-19, media outlets worried that “starving, cannibalistic” rats would take to the streets. The U.S. Centers for Disease Control and Prevention even offered tips for how to face hungry rodent masses. But there were no actual data to say whether the ratpocalypse was nigh. Now, there are. And the answer: New Yorkers are calling in fewer rats since the pandemic began, but in different places. “We had been hearing lots of headline-grabbing media stories,” but there were few numbers to back up the claims, says Jonathan Richardson. So the urban ecologist at the University of Richmond in Virginia and his colleagues gathered rat-related requests for public services in New York City and Tokyo. They also sent surveys out to pest control companies around the world. First, media outlets warn of the ratpocalypse every year. “Rat season is in warmer weather months,” Richardson says. “Numbers increase in April and increase to a peak between July and August.” This year, not so much. By comparing the city service calls from previous months and years with those during the pandemic, Richardson and his colleagues showed that in 2020, calls actually went down about 30 percent compared with previous years during March and April. But when Richardson and his colleagues compared the U.S. data with public service calls from Tokyo — also locked down for COVID-19 — the team found the opposite. Calls there were up 24 percent for a similar period, Richardson and his colleagues report in a study posted July 7 at medRxiv.org. That’s higher than normal, but nowhere near ratpocalypse levels.
7-12-20 Saving one of the world's rarest antelope
They used to be a fairly common sight on the Kenya-Somalia border, but in recent years the number of hirola, or Hunter's antelope, has dropped to fewer than 500 in the wild. They are now listed at critical risk of extinction. Abdullahi Hussein Ali has launched a conservation programme to help save them.
7-10-20 European bison to be introduced in the UK for first time outside zoos
The European bison will be introduced to the UK for the first time outside a zoo, in a move that conservationists hope will regenerate ecosystems and help other animals and plants thrive. Europe’s largest land mammal was reduced to just 54 individuals in the early 20th century, but reintroductions across continental Europe from the Netherlands to Romania have seen numbers swell to more than 5000. The UK will follow suit in early 2022 with an initial four Bison bonasus set for release in a controlled area of a nature reserve just outside Canterbury. “What is so sad is the UK is more informed about the state of our wildlife than any other country, yet we are so nature-depleted. This is a trial to see: can we do this, can we replicate what we’ve seen work successfully in Europe?” says Laura Gardner at the Wildwood Trust in the UK, which has been awarded £1.15 million from the People’s Postcode Lottery to fund the project. Working with Kent Wildlife Trust and several universities, the team at the Wildwood Trust hope to monitor how the huge grazers break up soil and open up spaces in the woods to bring back complexity to ecosystems. “It’s not just about how the bison interact directly with the landscape but the impact of that: what does it mean for soil quality, invertebrate abundance, the number of plant species,” says Gardner. The animals, which can stand almost 2 metres tall, will be fenced in a 500-hectare area away from footpaths. The project team hope to assuage any potential concerns from dog-walkers and ramblers by engaging with local people. Rebecca Wrigley at the UK charity Rewilding Britain, which isn’t involved in the scheme, says the plans “could be good news for Britain’s battered biodiversity” and provide people with “wilder experiences of nature”.
7-10-20 European bison to be introduced into Kent woodland
Bison will be introduced to UK woodland to restore an ancient habitat and its wildlife, conservationists have said. The £1m project, led by Kent Wildlife Trust and the Wildwood Trust, is aimed at helping to manage Blean Woods near Canterbury. A wild herd of European bison, the continent's largest land mammal, will be in their new home by spring 2022. The breed is the closest living relative to ancient steppe bison, which once roamed Britain. The charities will be preparing over the next 18 months, including creating a fenced enclosure. The bison will be within a wider 500 hectare (1,200 acre) area with other grazing animals such as Konik ponies, to create varied and healthy habitat, the conservationists said. Paul Hadaway, of Kent Wildlife Trust said: "A wilder, nature-based solution is the right one to tackling the climate and nature crisis we now face. "Using missing keystone species like bison to restore natural processes to habitats is the key to creating bio-abundance in our landscape." Paul Whitfield, director general of Wildwood Trust added: "This will allow people to experience nature in a way they haven't before." Adult males can weigh up to a tonne but bison are peaceful, according to the experts, and no other species could perform the job of engineering the habitat in quite the same way. They fell trees by rubbing up against them, creating areas of space and light in the woods, which help plants such as cow wheat to grow. The heath fritillary - a rare butterfly - depends on this plant. Patches of bare earth created by the bison dust bathing are good for lizards and rare arable weeds, while their bark stripping creates standing deadwood for fungi and insects such as stag beetles. The project is to be funded by £1,125,000 from the People's Postcode Lottery Dream Fund.
7-9-20 Dolphins and whales separately evolved the same speedy swimming bones
A 24-million-year-old fossil of a giant tusked dolphin lacks several features common to modern dolphins and baleen whales. The discovery shows that the common ancestor of dolphins and whales lacked these features, meaning the same adaptations for swimming must have evolved independently in both lineages. “We were surprised to find so many archaic features in an extinct dolphin,” says Robert Boessenecker at the College of Charleston in South Carolina. Ankylorhiza tiedemani was one of the top predators in the sea from around 30 to 23 million years ago. The 5-metre-long dolphin would have looked much like a bottlenose dolphin, says Boessenecker, apart from its front teeth. These stick straight out and may have been used for ramming prey. Boessenecker’s team has been studying an A. tiedemani fossil found in the 1990s. “No one had found such a complete skeleton before,” he says. It revealed an unexpected lack of modern features. Compared to ancient ancestors all modern whales and dolphins have extra vertebrae in their tails, giving them more flexibility and swimming power, and a very narrow base to the tail, just before the tail flukes. The “upper arm” bone in their pectoral flippers is very short relative to the other bones, and they have two or three extra finger bones. This helps make the flippers larger and stiffer, improving manoeuvreability. It has been assumed that these features all evolved before the ancestors of baleen whales split from the ancestors of echolocating dolphins around 35 million years ago, says Boessenecker, but the fossil shows these features are instead a result of convergent evolution. “All these features evolved at least twice,” he says. We don’t know what Ankylorhiza preyed on. But if it lived in pods it would have been able to eat just about anything it wanted, says Boessenecker – including the 13-metre-long predecessors of megalodon sharks that lived at this time.
7-9-20 Almost all lemur species are now endangered
This lemur species was once common across the south of Madagascar, but is now listed as critically endangered, the last category before extinction. The fate of Verreaux’s sifaka (Propithecus verreauxi) is sadly shared by many of its cousins, with an update of the International Union for the Conservation of Nature (IUCN) Red List today finding more than half of African primates outside Madagascar are now endangered to some extent. Due to rampant deforestation and hunting in their heartland of Madagascar, lemurs have it particularly bad: 103 of the world’s 107 species of these animals are threatened by extinction. A growing lemur pet trade in the country has also emerged as a new pressure. “Everything seems to be stacked up against lemurs,” says Russ Mittermeier at the IUCN. Local taboos about hunting Verreaux’s sifaka had previously helped the species, but with new people moving to the forests they occupy as charcoal production booms, that protection has evaporated. “It’s a wonderful, beautiful animal,” says Mittermeier. The species is active in the day, making it great for eco-tourism, which Mittermeier thinks is one of the best hopes of protecting Africa’s primates. He points to eco-tourism’s role in the conservation success story of mountain gorillas, but he fears for the loss of visitors due to the coronavirus pandemic. “If this thing lasts for two years, it’s going to be really bad,” he says. “We could start losing species, which would be absolutely awful.”
7-9-20 Extinction: One third of all lemurs 'on the brink'
A third of all the lemur species on Earth are "one step from extinction". This is according to the latest update of the Red List, the comprehensive, continually updated report on the status of species. Human activities, particularly deforestation and hunting, drive the declines in these unique primates. Such habitat destruction has also been linked to an increased risk of wildlife diseases - like the coronavirus - spilling over into human populations. The update shows that 33 lemur species - primates unique to Madagascar - are now classified as Critically Endangered, with 103 of the 107 surviving species threatened with extinction. Thirteen lemur species have been "uplisted" - pushed to higher threat categories as a result of these "intensifying human pressures". Craig Hilton-Taylor from the International Union for Conservation of Nature (IUCN), which produces the list, told BBC News that the current pandemic should give us pause to "ask some difficult questions about our relationship with the natural world". "We need to look to nature to provide future solutions to human problems - like treatments for disease and food supplies," Dr Hilton-Taylor added. "Nature has a huge amount to offer us, but if we continue to impact the natural world as we're doing - and if we lose species like lemurs - then our chances of looking to nature for those solutions is reduced dramatically." Updates to the list are based on the latest scientific assessments. There are now more than 120,000 different species that have been assessed, with 120,372 species now listed and, of these, 32,441 are threatened with extinction. There are some conservation success stories in the latest list. A little known species of iguana native to the Turks and Caicos Islands has been "downlisted" from Critically Endangered to Endangered, meaning it is no longer at immediate threat of extinction. That is entirely, Craig Hilton-Taylor said, because of a concerted conservation effort on the islands, involving the government, NGOs and local people - restoring habitat and reintroducing the species.
7-9-20 Rats will help others in distress, but they can be influenced not to
Rats will often help their fellows if they are in distress, but they can be influenced not to – if other rats seem uninterested in the situation. This so-called bystander effect has been studied in humans for 50 years. That it also exists in rats suggests it has deep evolutionary roots. However, the bystander effect doesn’t mean what many people have understood it to: that a person in distress is unlikely to receive help. The opposite is true. Research into the bystander effect was prompted by the 1964 murder of Catherine “Kitty” Genovese in New York City. A New York Times article claimed that 38 witnesses saw the killing unfold for over 30 minutes but didn’t help or raise the alarm. It was a shocking story, though it later emerged that most did not see enough to know what was happening. Psychologists soon found laboratory evidence that people were less likely to help if they were part of a crowd than if they were alone, says Peggy Mason at the University of Chicago in Illinois. But this had to be done in an artificial way using “confederates” – researchers instructed not to help. Mason’s team has now shown the same effect in rats. The team trapped one rat in a plastic tube that could only be opened from the outside by a second rat. Lone rats are quick and eager to help. “The only reason the rat does this is because it feels good,” says Mason. “We’re not giving any food.” This changed when additional rats were introduced. These “confederate” rats had been given midazolam, which reduced their emotional response to the trapped rat, so they didn’t try to help. Now the original rat became less likely to assist. This was the bystander effect in action. However, the team also performed a twist on the experiment, by introducing additional rats that weren’t drugged, but which hadn’t seen the tube before. These naive rats made the experienced rats more likely to help. “If you’re alone, it feels dicey to go in and intervene,” says Mason. “But if there’s three of you, that’s mitigated.”
7-4-20 Bizarre caecilians may be the only amphibians with venomous bites
Creatures that look like snakes appear to have glands near their teeth that secrete venom. Caecilians are amphibians like salamanders and frogs, but they’re often mistaken for snakes because of their long, legless bodies. Now, scientists think that the similarities between the two are more than skin deep. New microscope and chemical analyses suggest that, like snakes, caecilians have glands near their teeth that secrete toxins. The discovery raises the possibility that caecilians may be the first amphibians found capable of delivering a venomous bite. Pedro Mailho-Fontana, an evolutionary biologist with the Butantan Institute in São Paulo, has been studying caecilians for several years, and in particular, the glands in their skin. He has helped show that the animals have separate glands for secreting mucus on their heads and poison on their tails. But one day in early 2018, as Mailho-Fontana was slowly eroding the skin on the skull of a dead ringed caecilian (Siphonops annulatus) to get a closer look at the mucus glands, he saw something that made his hair stand on end: large glands in the animal’s upper and lower jaws that had ducts going to the teeth. Mailho-Fontana, along with fellow evolutionary biologists Marta Antoniazzi and Carlos Jared also at the Butantan Insitutue, set about characterizing these unexpected oral glands in several caecilian species using standard and electron microscopes. Perhaps the most striking finding is that the glands arise from dental tissue. That’s just like venom glands of snakes, but it’s a first for amphibians, the researchers report July 3 in iScience. The team also performed preliminary biochemical tests on the fluid in the newfound glands, and discovered that it contains phospholipase A2 enzymes, a large group of fat-chopping proteins that are frequent components in animal venoms. But the work stopped short of conclusively showing that the animals are venomous.
7-3-20 Supermarkets snub coconut goods picked by monkeys
A number of supermarkets have removed some coconut water and oil from their shelves after it emerged the products were made with fruit picked by monkeys. The monkeys are snatched from the wild and trained to pick up to 1,000 coconuts a day, People for the Ethical Treatment of Animals (Peta) said. The animal rights group said pigtailed macaques in Thailand were treated like "coconut-picking machines". In response Waitrose, Ocado, Co-op and Boots vowed to stop selling some goods. Meanwhile, Morrisons said it had already removed products made with monkey-picked coconuts from its shelves. In a statement, Waitrose said: "As part of our animal welfare policy, we have committed to never knowingly sell any products sourced from monkey labour." Co-op said: "As an ethical retailer, we do not permit the use of monkey labour to source ingredients for our products." In a tweet earlier on Friday, the prime minister's fiancée Carrie Symonds, a conservationist, called on all supermarkets to boycott the products. Sainsbury's subsequently told the BBC: "We are actively reviewing our ranges and investigating this complex issue with our suppliers." Asda said: "We expect our suppliers to uphold the highest production standards at all times and we will not tolerate any forms of animal abuse in our supply chain." It pledged to remove certain brands from its shelves until it has investigated the allegations of cruelty. Ms Symonds later took to Twitter again to urge Tesco to make a similar pledge: "Come on @Tesco! Over to you! Please stop selling these products too," she wrote. Tesco did not immediately respond to the BBC's request for comment. Peta said it had found eight farms in Thailand where monkeys were forced to pick coconuts for export around the world. Male monkeys are able to pick up to 1,000 coconuts a day, Peta says. It's thought that a human can pick about 80. It said it also discovered "monkey schools", where the animals were trained to pick fruit, as well as ride bikes or play basketball for the entertainment of tourists. "The animals at these facilities - many of whom are illegally captured as babies - displayed stereotypic behaviour indicative of extreme stress," Peta said.
7-3-20 A sparrow song remix took over North America with astonishing speed
A variation on the white-throated sparrow’s song spread 3,300 kilometers in just a few decades. Some North American birds are changing their tune. The traditional song of the white-throated sparrow (Zonotrichia albicollis) ends with a repeated triplet of notes. By 2000, however, some birds in western Canada were whistling a variation ending in a two-note pattern. That new song has since spread widely across North America, researchers report online July 2 in Current Biology. The findings fly in the face of previous hypotheses that birdsong dialects don’t change much within local regions. The rapid spread of the new song is akin to someone moving from Kentucky to Vancouver and everyone in Vancouver suddenly picking up a Kentucky accent, says Ken Otter, an avian behavioral ecologist at the University of Northern British Columbia in Prince George, Canada. Otter and his colleagues documented the adoption of the western song at a research station in eastern Canada. In 2005, only one male out of 76 surveyed sang the doublet-ending song. In 2014, 22 percent of 101 males surveyed sang the new song. And in 2017, nearly half of 92 males recorded had adopted the variation. “You can actually see the [transition] unfolding in real time,” says Jeff Podos, a biologist who studies animal communication at the University of Massachusetts Amherst and was not involved with the study. The researchers confirmed the spread of the song with the double-noted ending across the continent — as far east as Quebec and Vermont — via recordings from citizen scientists. Eastern sparrows probably picked up the new song at common wintering grounds, the researchers say (SN: 2/4/16). By tracking birds from central British Columbia with backpacklike geolocators, the team found that the birds migrated to the southern U.S. Great Plains, which overlap with known wintering grounds of birds that breed east of the Rockies. One explanation for this shift may be a female preference for novel songs, a focus for future study, Otter says.
7-2-20 Canadian sparrows are ditching traditional songs for a new tune
A new style of song is sweeping through Canada, pushing out traditional tunes – at least in certain birds. The new singing style arose in a semi-isolated population in western Canada, but has since been heard as far as 3000 kilometres to the east. “The dialect, or song type, is spreading so rapidly,” says Ken Otter of the University of Northern British Columbia in Prince George, Canada. Otter and his colleagues have been studying white-throated sparrows (Zonotrichia albicollis) for 20 years. These songbirds spend summer breeding in Canada and the north-eastern US, and winter in the southern and eastern US. When Otter first went into the field near Prince George, he rediscovered the only breeding population of white-throated sparrows west of the Rocky Mountains. He recorded some of the males’ songs, and his colleague Scott Ramsay, now at Wilfrid Laurier University in Waterloo, Canada noticed that some of them were peculiar. Male white-throated sparrows sing a whistling song that ends with repeated triplets. But the Prince George sparrows replaced the triplets with double notes. Otter says the triplet version has the same rhythm as “oh my sweet Canada Canada Canada Canada”, but the double version is more like “oh my sweet Cana Cana Cana Cana”. The new song seems to have arisen in the western population sometime between the 1950s and 2000: 1950s recordings show the birds singing the triplet version. To track its spread, Otter and his colleagues recorded the birds themselves, and obtained additional recordings made by colleagues and citizen scientists across the US in the past 20 years. They ultimately gathered 1785 songs. Many of the bird populations east of the Rockies are now singing the double note-ending songs. In one population numbers rose slowly for a decade, then shot up. “You get this slow adoption and then when enough birds are singing it, then it escalates,” says Otter.
7-1-20 Hundreds of elephants found dead in Botswana
Mystery surrounds the "completely unprecedented" deaths of hundreds of elephants in Botswana over the last two months. Dr Niall McCann said colleagues in the southern African country had spotted more than 350 elephant carcasses in the Okavango Delta since the start of May. No one knows why the animals are dying, with lab results on samples still weeks away, according to the government. Botswana is home to a third of Africa's declining elephant population. Back in May, Botswana's government ruled out poaching as a reason - noting the tusks had not been removed, according to Phys.org. There are other things which point to something other than poaching. "It is only elephants that are dying and nothing else," Dr McCann said. "If it was cyanide used by poachers, you would expect to see other deaths." Dr McCann has also tentatively ruled out natural anthrax poisoning, which killed at least 100 elephants in Bostwana last year. But they have been unable to rule out either poisoning or disease. The way the animals appear to be dying - many dropping on their faces - and sightings of other elephants walking in circles points to something potentially attacking their neurological systems, Dr McCann said. Either way, without knowing the source, it is impossible to rule out the possibility of a disease crossing into the human population - especially if the cause is in either the water sources or the soil. Dr McCann points to the Covid-19 pandemic, which is believed to have started in animals. "Yes, it is a conservation disaster - but it also has the potential to be a public health crisis," he said. Dr Cyril Taolo, acting director for Botswana's department of wildlife and national parks, told the Guardian they had so far confirmed at least 280 elephants had died, and were in the process of confirming the rest. However, they did not know what was causing the animals' deaths. "We have sent [samples] off for testing and we are expecting the results over the next couple of weeks or so," he said.