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Tag: animals

  • Recluse Spider Season Is a Myth

    Recluse Spider Season Is a Myth

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    This story originally appeared on WIRED en Español and has been translated from Spanish.

    Summer arrives, and with it comes an arachnophobic furor—frantic reports about the intrusion of recluse spiders into our homes. Also known as fiddlebacks or violin spiders, these are arachnids of the genus Loxosceles. They’re found in warm areas across the world, including many parts of the USA, and particularly in Mexico, which has the greatest diversity of recluse spiders in the world, with 40 different species.

    Headlines declare that the start of May is “recluse spider season,” and that people need to watch out. It’s true that in their fangs these spiders carry a potent venom, which under certain circumstances can be lethal, but really they are elusive creatures that almost always seek to remain unnoticed. We should not get carried away with anti-fiddleback hysteria, much less replicate it. Such anxiety is unscientific, says Diego Barrales Alcalá, the creator of the arachnid identification platform @Arachno_Cosas. The idea of a supposed season of recluse spiders, promulgated by the media, lacks evidence.

    “Fiddlers have become the favorite villain and, unfortunately, according to what I have seen, the problem is cyclical. Every so often the ‘season’ arrives. But not of fiddlers, but of fake news,” Barrales Alcalá says. The activity of these arachnids doesn’t vary according to the time of the year, he says. And in his native Mexico, what limited statistics there are on bites certainly don’t add up to the concern seen in the media.

    Geographic coverage of humanspider encounters in the analyzed database published in Nature. In blue encounters with...

    Geographic coverage of human-spider encounters, 2010 and 2020, based on 5,000+ news articles from 81 countries, published in Nature. In blue, encounters with fiddler spiders; in orange, bites; in red, fatal bites.Illustration: Nature

    While recluse spiders choose to inhabit our homes, they are not aggressive. Usually they live away from people, in cellars and uncrowded areas of the house. Bites, when they do happen, occur typically when there’s unintentional contact between humans and spiders or due to people deliberately trying to manipulate them.

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  • Sick chimpanzees seek out range of plants with medicinal properties

    Sick chimpanzees seek out range of plants with medicinal properties

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    A chimpanzee in Budongo Forest, Uganda, feeding on the fruit of a sandpaper tree (Ficus exasperata)

    Elodie Freymann (CC-BY)

    Several plants eaten by chimpanzees when they are ill or wounded have been found to have medicinal effects, providing some of the strongest evidence yet that our close relatives practise self-medication.

    Reports of chimpanzees self-medicating with plants have been around for decades, but it is difficult to establish when wild animals are ill and what effect their diet has.

    Elodie Freymann at the University of Oxford and her colleagues followed wild chimps through Budongo Forest in Uganda, recording when they were ill and what they ate. The researchers identified chimps with obvious wounds or with gut infections by analysing their faeces for signs of intestinal worms, as well as checking urine samples for raised levels of immune cells.

    Analysis of 53 extracts of plants consumed by the ill or injured chimps showed that 88 per cent were active against bacteria that are pathogenic in humans, including antibiotic-resistant strains like MRSA. Extracts from every sampled species had anti-inflammatory effects.

    Such a systematic approach allowed the researchers to identify and characterise the species that the chimps use beyond what had been done before, says Kirsty Graham at the University of St Andrews, UK, who wasn’t involved in the study. “It’s a very impressive project.”

    Sick chimps often left the safety of their group to eat specific plants, and picked out species only rarely eaten at the site. The infrequency of these events is what makes self-medication behaviour so hard to observe, but also provides one of the strongest pieces of evidence that it is a targeted response to illness.

    Chimpanzees are usually reluctant to try unfamiliar foods that might be dangerous, says Freymann. Choosing to eat unusual plants therefore suggests they have particular reasons for doing so. “If you’re sick, you’re not going around stuffing things that could make you sicker in your mouth,” she says.

    This might not capture everything that is going on, though, says Graham, as chimps’ diets are still very diverse. If the animals learn which plants to eat from others, over generations the community might overcome this reticence towards new foods. Directly comparing the diets of sick and healthy chimps at the same time might clarify whether these are active choices, she suggests.

    Team member Fabien Schultz at the Brandenburg University of Applied Sciences in Germany hopes that identifying the active compounds in the plant extracts might lead to promising candidates for human medicines. “What if human lives can be saved by following the ways of our animal relatives?” he says.

    An orangutan, another member of the great ape family, was seen applying plant leaves directly onto a wound in an apparent act of self-medication reported this year.

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  • Watch leeches jump by coiling their bodies like cobras

    Watch leeches jump by coiling their bodies like cobras

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    For the first time, scientists have captured video of leeches leaping from leaves, settling a centuries-long dispute over the bloodsuckers’ ability to jump.

    The question of whether leeches can jump has been debated since rumours of the behaviour emerged in the late 1800s. There have been occasional sightings since, but this is the first conclusive evidence.

    Mai Fahmy at Fordham University in New York documented this ability in 2017 while doing fieldwork in Madagascar. During a hike, she encountered a Chtonobdella leech (Chtonobdella fallax) – an earthworm-sized animal that lives solely in Madagascar.

    “I squatted next to it on the ground, and I took out my phone and started recording,” says Fahmy. “At the time, I didn’t realise what I had captured.” When she showed the video to her colleagues back in New York, Fahmy says they all had the same reaction: did that leech just jump?

    Six years later, Fahmy returned to Madagascar to try to record another jumping leech and once again found quick success. This time, two leeches were interacting before one leapt from a leaf.

    The leeches prepare by anchoring their rear sucker to a surface – in this case, a leaf – and coiling the rest of their body backwards. Then, in one rapid motion, they launch their body forward, much like a striking cobra, unsticking their rear sucker and becoming airborne.

    The sudden burst of movement may be a tactic to land on or near unsuspecting prey. The leap is a bit awkward, but “this is very clearly an active form of propulsion”, says Michael Tessler at Medgar Evers College in New York.

    Land-living leeches have not been closely studied, despite their ability to help conservationists track down hard-to-spot animals by analysing the blood from these creatures that the leeches have sipped. But finding this ability in two different individuals and locations “suggests that this behaviour is more common than we might have anticipated”, says Tessler. Based on this evidence and anecdotal stories from other regions, he suspects these are not the world’s only jumping leeches.

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  • Lokiceratops: Triceratops relative had the weirdest horns ever seen on a dinosaur

    Lokiceratops: Triceratops relative had the weirdest horns ever seen on a dinosaur

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    Artist’s impression of Lokiceratops encountering a crocodilian in the 78-million-year-old swamps of northern Montana

    ©Andrey Atuchin for the Museum of Evolution in Maribo, Denmark.

    A newly discovered relative of Triceratops had a unique array of head ornaments, including the largest frill horns ever seen on a horned dinosaur.

    The fossil remains of the dinosaur were found in 2019 on private property near the US/Canada border in Montana. They were purchased by the Museum of Evolution in Denmark, where they are currently on display.

    It is thought that the creature lived around 78 million years ago and would have been about 6.7 metres long, weighing around 5 tonnes.

    Lokiceratops rangiformis, as it has been named, had two long horns at the front of its head as well as three main horns on the frill at the back of its head. The largest frill horns, positioned on each side of the skull, were flat, broad and curving in a scimitar-like shape.

    They were probably used for display rather than defence, says Joseph Sertich at Colorado State University, and measured more than 60 centimetres long on their outer curve. “By absolute volume and length, Lokiceratops had the largest frill horns ever seen,” says Sertich.

    When it lived, about 12 million years before its most famous relative Triceratops, its home in what is now the western part of North America was an island continent named Laramidia.

    Several other dinosaurs from the Ceratopsid family have been found in the same fossil assemblage. “This is the first interval where five horned dinosaurs have been found living at the same place and time,” says Sertich.

    Mark Loewen at the University of Utah coined the name of the fossil after the Norse god Loki because its permanent home is now Denmark. The species name, rangiformis, refers to the resemblance between the dinosaur’s asymmetric middle-frill horns and the asymmetric front tines, or branches, of reindeer antlers.

    “Many modern deer have asymmetrical antlers,” says Loewen. “We also know that asymmetry is not uncommon in horned dinosaurs, but it is striking in Lokiceratops.”

    Erich Fitzgerald at Museums Victoria in Melbourne, Australia, says the discovery reveals the extraordinary biodiversity of the Ceratopsid dinosaurs that evolved in the Late Cretaceous epoch of western North America.

    “This research really accentuates the difference between the rich-horned dinosaur fauna of 80 to 70 million years ago, with that of the end-Cretaceous times, some 66 to 68 million years ago – when Triceratops dominated a lower-diversity fauna of horned behemoths,” says Fitzgerald.

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  • With So Much Bird Flu Around, Are Eggs, Chicken, and Milk Still Safe to Consume?

    With So Much Bird Flu Around, Are Eggs, Chicken, and Milk Still Safe to Consume?

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    This article is republished from The Conversation under a Creative Commons license.

    Recent outbreaks of bird flu—in US dairy herds, poultry farms in Australia, and elsewhere, and isolated cases in humans—have raised the issue of food safety.

    So can the virus transfer from infected farm animals to contaminate milk, meat, or eggs? How likely is this? And what do we need to think about to minimize our risk when shopping for or preparing food?

    How Safe Is Milk?

    Bird flu (or avian influenza) is a bird disease caused by specific types of influenza virus. But the virus can also infect cows. In the US, to date, more than 80 dairy herds in at least nine states have been infected with the H5N1 version of the virus.

    Investigations are under way to confirm how this happened. But we do know that infected birds can shed the virus in their saliva, nasal secretions, and feces. So bird flu can potentially contaminate animal-derived food products during processing and manufacturing.

    Indeed, fragments of bird flu genetic material (RNA) were found in cow’s milk from the dairy herds associated with infected US farmers.

    However, the spread of bird flu among cattle, and possibly to humans, is likely to have been caused through contact with contaminated milking equipment, not the milk itself.

    The test used to detect the virus in milk—which uses PCR technology similar to lab-based Covid tests—is also highly sensitive. This means it can detect very low levels of the bird flu RNA. But the test does not distinguish between live or inactivated virus, just that the RNA is present. So from this test alone, we cannot tell if the virus found in milk is infectious (and capable of infecting humans).

    Does that mean milk is safe to drink and won’t transmit bird flu? Yes and no.

    In Australia, where bird flu has not been reported in dairy cattle, the answer is yes. It is safe to drink milk and milk products made from Australian milk. In the US, the answer depends on whether the milk is pasteurized. We know pasteurization is a common and reliable method of destroying concerning microbes, including influenza virus. Like most viruses, influenza virus (including bird flu virus) is inactivated by heat.

    Although there is little direct research on whether pasteurization inactivates H5N1 in milk, we can extrapolate from what we know about heat inactivation of H5N1 in chicken and eggs. So we can be confident there is no risk of bird flu transmission via pasteurized milk or milk products.

    However, it’s another matter for unpasteurized or “raw” US milk or milk products. A recent study showed that mice fed raw milk contaminated with bird flu developed signs of illness. So to be on the safe side, it would be advisable to avoid raw milk products.

    How About Chicken?

    Bird flu has caused sporadic outbreaks in wild birds and domestic poultry worldwide, including in Australia. In recent weeks, there have been three reported outbreaks in Victorian poultry farms (two with H7N3 bird flu, one with H7N9). There has been one reported outbreak in Western Australia (H9N2).

    The strains of bird flu identified in the Victorian and Western Australia outbreaks can cause human infection, although these are rare and typically result from close contact with infected live birds or contaminated environments. Therefore, the chance of bird flu transmission in chicken meat is remote.

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  • Tiny great ape fossils identified as new species from Europe

    Tiny great ape fossils identified as new species from Europe

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    Two teeth, viewed from multiple angles, from the newly identified ancient ape Buronius manfredschmidi

    Böhme et al., 2024, PLOS ONE, CC-BY 4.0

    A tiny, vegetarian great ape may have lived in western Europe 11.6 million years ago. Smaller and lighter than any other known great ape, the newly discovered 10-kilogram primate was a skilled climber that probably ate leaves, says Madelaine Böhme at the University of Tübingen in Germany.

    “It’s quite a small primate,” she says. “But it differs from all known fossils and, of course, all living great apes we know so far.”

    About 15 million years ago, in the middle of the Miocene Epoch, hominoids – the great apes – became rarer in Africa and more abundant in Europe. While they sometimes shared habitats with other primates such as pliopithecoids – extinct cousins of apes and Old World monkeys – hominoid species didn’t appear to coexist with each other in Europe.

    In 2019, Böhme and her colleagues reported the discovery of 37 bones at Bavaria’s Hammerschmiede archaeological site that appeared to come from an early bipedal ape from 11.6 million years ago, which they named Danuvius guggenmosi.

    During the excavations, Böhme was surprised when she found two tiny, ape-like teeth and a kneecap in the same layer of sediment as the Danuvius fossils.

    “We kept saying: ‘What is this?’” she says of these smaller fossils. “And then we decided, OK, it’s clear: this is something new.”

    The fossils are too old for DNA analysis, says Böhme. So the researchers took detailed measurements of the 7-millimetre-long molar and the 16-millimetre-wide kneecap, both from a juvenile, as well as a smaller premolar fragment, which they say came from a young adult. They also calculated the thickness of the enamel and ran microscopic CT scanning of the teeth.

    The thin enamel, like that of gorillas, suggests a soft diet probably composed of leaves, says Böhme. The shape, thickness and ligament attachment sites of the kneecap resemble those of tree-living primates, hinting that the ape was a proficient climber.

    The researchers named the new ape Buronius manfredschmidi, after the medieval name of a city near the Hammerschmiede site, and a dentist named Manfred Schmid who has been collecting fossils from the site since the 1970s.

    Lack of competition for resources might explain why the Buronius and Danuvius apes could live together, says Böhme – Danuvius is thought to have eaten hard foods like nuts and possibly meat. The team cannot rule out the possibility that the larger ape, which might have been up to three times heavier, may have sometimes fed on the smaller species, she adds.

    However, the three fossils might not be sufficient to make such “grandiloquent” conclusions, says Sergio Almécija at the American Museum of Natural History in New York City. “Could the smaller fossil elements belong to an infantile Danuvius individual?” he asks. “The teeth certainly look like they could be deciduous [baby teeth].”

    He also wonders whether the kneecap represents the same species as the teeth. “Even though it is suggested that it belongs to a juvenile individual, its size overlaps with the lower range of adult orangutans [which are much larger apes],” says Almécija.

    Clément Zanolli at the University of Bordeaux, in France, also has doubts. “It is not very clear to me if the teeth – and in particular the molar – belong to the hominoids or to another primate superfamily, the pliopithecoids.”

    Böhme and her colleagues say their comparisons ruled out the possibility that the teeth are baby teeth or pliopithecoid teeth.

    In any case, the possibility that two primate species shared the same habitat and perhaps even interacted with each other is a “fantastic discovery”, says Zanolli. “This shows once again that, at that time, Europe was a luxurious and hospitable place for primates to evolve.”

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  • Male lemurs grow bigger testicles when there are other males around

    Male lemurs grow bigger testicles when there are other males around

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    A male Verreaux’s sifaka

    Gabrielle Bueno

    Dominant male lemurs flexibly grow their testicles when other males are around, putting them in a better position to successfully mate.

    In many species, dominant males have larger testes than subordinates, often because they have more testosterone. Studies have also shown that males in species that have lots of males living together have bigger testicles than in species where only one male lives in a group. Because larger testicles can make more sperm, this improves a male’s chances of fathering offspring if females mate with several males.

    Gabrielle Bueno and Rebecca Lewis from the University of Texas at Austin tested if this pattern holds true within a single population by looking at the testes size of 23 adult male Verreaux’s sifakas (Propithecus verreauxi) in Kirindy Mitea National Park in western Madagascar. This was done outside the mating season over a 13-year period.

    This population of lemurs is made up of several groups, with some having only one male and others having multiple males. Although females hold the most social power, as in all lemur societies, males also have their own hierarchy. Dominant ones have a brown, greasy stain on their chest due to constant scent marking, whereas subordinates have clean white torsos.

    The researchers found that stained males in multi-male groups have testicles that are, on average, 103 per cent larger than those of clean males within their group, and 31 per cent larger than those of stained males in single-male units. The stained lemurs in multi-male groups may be producing more testosterone than the other lemurs, or suppressing the amount of testosterone the clean males can produce, says Bueno.

    Stained males in multi-male groups don’t just have more sizeable scrotums in absolute terms – they are also larger relative to their body size. Bueno says that this shows dominant males invest more energy in sperm competition when there are other males around.

    “Importantly, they are able to switch that,” says Bueno. The dominant male always has the biggest testicles, so if a clean male with larger testes enters the group, the stained male’s gonads grow. This “highlights how insanely flexible they are and how in tune they are with their social environment”, says Bueno.

    “The flexible adjustment of testes size of males living under different conditions across their lifespan is remarkable,” says Peter Kappeler at the University of Göttingen in Germany. This raises important questions about the potential costs of maintaining large testes, he adds. Growing larger testicles uses up energy that then can’t be spent elsewhere, and is likely to mean they have to find more food.

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  • Origins of modern horses traced to breeding revolution 4200 years ago

    Origins of modern horses traced to breeding revolution 4200 years ago

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    The domestication of horses began on the Eurasian steppes

    Lina Shatalova/iStockphoto/Ge​tty Images

    Ancient breeders dramatically shortened the natural generation times of horses starting about 4200 years ago, according to a genetic study of hundreds of ancient horses. This intensive breeding led to a massive expansion of those bloodlines across Eurasia within a few centuries, says Ludovic Orlando at the Centre for Anthropobiology and Genomics of Toulouse, France.

    “In other words, they controlled the reproduction of the horse,” he says. “So this tells us something about the process of breeding that was underlying the success of the expansion of horses around the world.”

    Horses were first domesticated 5500 years ago by the Botaï people in what is now Kazakhstan, but they didn’t spread their horse culture elsewhere, says Orlando. The Botaï eventually died out and their horses returned to the wild.

    More than a thousand years later, however, a different line of horses became domesticated in the Pontic-Caspian steppes of southern Russia. It was this line that ultimately spread across the planet, leading to every domestic horse in the world today, he says.

    To chart the history of horse husbandry, Orlando and his colleagues analysed the genomes of 475 ancient horses from Eurasia dating up to 50,000 years ago. They compared those with the genomes of 71 modern domestic horses representing 40 breeds worldwide, as well as six endangered Przewalski’s horses – which are a different sub-species.

    The team confirmed that horses prior to the third millennium BC weren’t being bred or domesticated – except among the Botaï. This means horses didn’t contribute to human migrations and cultural expansions before that time, contrary to some theories, says Orlando.

    The DNA analysis revealed significant inbreeding 4200 years ago in the Pontic-Caspian steppe horses, probably because people aimed to develop specific traits that make high-quality riding and chariot horses, he says.

    Then, using a new technique combining genome sequencing and carbon dating, the scientists were able to estimate the average number of years between two successive generations, which Orlando calls the generational time interval. That interval got remarkably shorter – half as long as in the wild – during the same period of massive inbreeding in the Pontic-Caspian steppes.

    “Right at the time of the domestication bottleneck, around 2200 BC, this is when breeders managed to control the reproduction of the horse so much that generations were ticking faster and faster,” says Orlando.

    Orlando suspects the breeders were probably shortening generations by having them mate at younger ages than they would in the wild, he said at the International Havemeyer Foundation Horse Genome Workshop, which took place last month in Caen, France.

    Christine Aurich at the University of Veterinary Medicine Vienna suspects the shortened generations were probably due to better survival rates rather than younger breeding ages. Horses give birth lying down in open grasslands, making them highly susceptible to predators until the foal can run, several hours later. Plus, any disturbances could prevent the foal from drinking its first milk – which always leads to death.

    “It must be assumed that for horses living in the care of humans, losses of mares and their newborn foals were considerably reduced in comparison to horses living under wildlife conditions,” says Aurich.

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  • How bats pick out their own calls when flying in enormous swarms

    How bats pick out their own calls when flying in enormous swarms

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    A swarm of hundreds of thousands of bats roosts in the Jornada caves in New Mexico

    Laura Kloepper

    A trained hawk carried sensors through a swarm of hundreds of thousands of bats, recording data that helped researchers figure out how the flying mammals manage to pick out their own high-pitched echoes from those of other chatty bats.

    If you have ever carried on a conversation in a noisy crowd, you have solved what is known as the cocktail party problem, focusing on a single voice among many. This isn’t just a human…

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  • Endangered giant pangolin spotted in Senegal after nearly 24 years

    Endangered giant pangolin spotted in Senegal after nearly 24 years

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    A rare sighting of a giant pangolin revives hopes for the species’ survival in West Africa, despite threats from poaching and deforestation

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