All posts tagged: animal behaviour

Parrot uses his broken beak to become a dominant male

Parrot uses his broken beak to become a dominant male

Published by skeptic

Bruce is a kea with just half a beak Ximena Nelson In 2013, things were looking bleak for a malnourished, undersized parrot who was missing half his beak and struggling to survive in the wilds of Arthur’s Pass in New Zealand’s South Island. Then, says Ximena Nelson at the University of Canterbury, New Zealand, one of her students came across the struggling kea (Nestor notabilis). The bird had lost the upper part of its beak, probably due to trauma. Because the kea is classified as an endangered species, the student decided to bring him into captivity. Little did anyone know that this was a decision that would change the bird’s life and thrust greatness upon him. The carers at Willowbank Wildlife Reserve in Christchurch, New Zealand, named the bird Kati, assuming that such a small parrot must have been a female. That assumption also made sense because it was the top half of the beak that the bird lacked. The upper beak is huge in male kea, and used for digging. It looks “like it …

Ancient giant kangaroos could have hopped despite their huge size

Ancient giant kangaroos could have hopped despite their huge size

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Procoptodon goliah was 2 metres tall, but it might have hopped MICHAEL LONG/SCIENCE PHOTO LIBRARY Even the giant kangaroos that roamed Australia thousands of years ago might have been able to hop, according to a new analysis of bones. Some of the kangaroos living during the Pleistocene were more than twice as heavy as those that live today. One group, the sthenurines, were so bulky that it was thought they couldn’t possibly hop – they must only have walked on their hind legs. “Sthenurines are what most people are talking about when they talk about giant kangaroos. They’re the really weird ones,” says Megan Jones at the University of Manchester, UK. “They have these really short, boxy skulls and a single toe on each foot. A large male red kangaroo is the biggest you’re going to get today, at about 90 kilograms, but the largest sthenurine was about 250 kilograms.” That giant was Procoptodon goliah, the biggest kangaroo species known to have existed, standing at about 2 metres tall. It died out about 40,000 years …

How fear drastically shapes ecosystems: Best ideas of the century

How fear drastically shapes ecosystems: Best ideas of the century

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When wolves were reintroduced to Yellowstone National Park in 1995, the effects were dramatic. Among other things, elk numbers fell far more than expected. It turns out that the mere fear of wolves was having a big impact. In places where elk thought wolves might be present, they spent much more time looking out for them, leaving less time to feed. In a paper published in 2001, biologist John Laundré, who died in 2021, used the term “landscape of fear” to describe this effect. The idea wasn’t entirely new. Previous lab experiments had shown that fear of predators alone can affect prey. Yet the prevailing view at the time was that predators affect wild prey populations only through direct predation. Laundré and others’ observations suggested this was wrong, but they didn’t demonstrate causality. That’s what Liana Zanette at Western University in Ontario, Canada, has done through a series of experiments over the past two decades. In British Columbia, Zanette and her colleagues played recordings of predators near wild song sparrows. Fewer eggs were laid, fewer hatched and fewer hatchlings survived. Overall, less than half as many lived compared with those …

Fossil may solve mystery of what one of the weirdest ever animals ate

Fossil may solve mystery of what one of the weirdest ever animals ate

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Hallucigenia, one of the strangest animals of all time Alamy One of the weirdest animals that ever lived may have been a scavenger. A re-examination of fossils first described in the 1970s seems to show a swarm of Hallucigenia feeding on the corpse of a comb jelly. Hallucigenia was a small animal, up to 5 centimetres long. It had a worm-like body with multiple legs, as well as long, sharp spines on its back. Because of its peculiar appearance, palaeontologists at first reconstructed the animal upside-down, supposing the spines to be legs. It lived in the deep seas during the Cambrian period (about 539 million to 487 million years ago), when many major animal groups emerged. Hallucigenia was first identified in rocks from the Burgess Shale deposits in British Columbia, Canada. It is related to velvet worms, tardigrades and arthropods (the group that includes insects and spiders). Little is known about the ancient animal’s lifestyle. For instance, none of the Hallucigenia fossils found to date have preserved gut contents, so we don’t know what they …

Is there an evolutionary reason for same-sex sexual behaviour?

Is there an evolutionary reason for same-sex sexual behaviour?

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A male Hamadryas baboon (Papio hamadryas) displays his dominant status by mounting a lower-ranking male Ger Bosma/Alamy Same-sex sexual behaviour may help monkeys and apes rise up the social ranks and ultimately have more offspring – and it seems to be especially beneficial in harsh environments where there are lots of predators, say, or a shortage of food. That’s the implication of a study looking at why the level of same-sex behaviour varies in different primate species. It supports the idea that, contrary to what is commonly assumed, same-sex sexual behaviours in apes and monkeys are an adaptive trait that boosts survival. It has often been claimed that same-sex behaviour is somehow “unnatural”. But in addition to people, it has now been reported in at least 1500 animals, from insects and dolphins to bison and bonobos. There are many reasons to think this is the tip of the iceberg. Most species haven’t been closely studied; same-sex behaviours often aren’t recognised when seen because the sexes of the individuals involved may not be clear; and even …

Jellyfish sleep about as much as humans do – and nap like us too

Jellyfish sleep about as much as humans do – and nap like us too

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An upside-down jellyfish in its natural habit on the seabed Eilat. Gil Koplovitch Jellyfish seem to sleep for about 8 hours a day, take midday naps and snooze more after a bad night’s sleep – just like us. Sleep is thought to have first evolved in marine creatures like these, and having a better understanding of their precise sleep patterns may help explain why it came about at all. “It’s funny: just like humans, they spend about a third of their time asleep,” says Lior Appelbaum at Bar-Ilan University in Ramat Gan, Israel. In animals with brains, such as mammals, sleep is crucial for things like storing memories and clearing metabolic waste from the brain. But it was unclear why sleep evolved in jellyfish, which belong to a group of brainless animals called cnidarians, in which neurons – arranged in a relatively simple network across the body – are also thought to have first evolved. Appelbaum and his colleagues used cameras to record Cassiopea andromeda, a species of upside-down jellyfish, in tanks for 24 hours. …

Killer whales and dolphins are ‘being friends’ to hunt salmon together

Killer whales and dolphins are ‘being friends’ to hunt salmon together

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A Pacific white-sided dolphin approaching a killer whale, as recorded from a camera worn by the killer whale University of British Columbia (A.Trites), Dalhousie University (S. Fortune), Hakai Institute (K. Holmes), Leibniz Institute for Zoo and Wildlife Research (X. Cheng) Killer whales and dolphins have been working together to hunt salmon in the northern Pacific Ocean, an unexpected finding that further reveals the complex social lives of marine mammals. Video cameras and sensors attached to nine killer whales – also known as orcas – showed four of them diving with numerous Pacific white-sided dolphins towards Chinook salmon hiding in the depths off northern Vancouver Island. Three more whales were observed by drone. The orcas ate the salmon, while the dolphins scavenged the scraps. “They were cooperatively foraging,” says Sarah Fortune at Dalhousie University in Canada. “You could anthropomorphise it and say that they’re being friends for hunting purposes.” Also known as king salmon, Chinook salmon can grow more than a metre long and are often too big for dolphins to eat. But northern Vancouver Island …

Mouse ‘midwives’ help their pregnant companions give birth

Mouse ‘midwives’ help their pregnant companions give birth

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Adult mice used their paws and mouths to remove pups stuck in a pregnant female’s birth canal Violet J. Ivan/NYU Grossman School of Medicine Mice seem to assist pregnant females when they get into difficulty giving birth, with experienced mothers being the most helpful. This is thought to be the first official sighting of such assistance in non-primates, and so expands our knowledge of caregiving behaviours across the animal kingdom. Humans are the only animal known to aid one another consistently during birth, which is a particularly lengthy and painful process in humans because our babies have large heads and must travel down a relatively narrow birth canal. Other primates, such as black snub-nosed monkeys and bonobos, have also been seen helping one another give birth, but only occasionally. Now, researchers have observed the same behaviour in mice. Robert Froemke at NYU Langone Health in New York City and his colleagues spotted it while recording the brain activity of mice that were giving birth as part of a separate study. They found that other mice …