Whale sharks gulp down air to float vertically while feeding

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A whale shark feeding at the water’s surface

Reinhard Dirscherl/Alamy

Whale sharks are the world’s largest living fish, measuring up to 18 metres long, but somehow they can suspend themselves in an upright position despite having a body density that is greater than that of seawater. A study of captive whale sharks suggests this may be due to air they take in as they feed at the water’s surface.

Scientists have previously observed whale sharks (Rhincodon typus) feeding vertically in the wild. Although they often use slow fin movements to …

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Rare video of giant squid reveals it stalks jellyfish in deep water

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In the first footage of its kind, researchers have filmed a giant squid stalking an electronic decoy jellyfish (E-Jelly) before striking it with lightning-quick speed. The video suggests that giant squid survive deep under the surface by being efficient hunters rather than waiting in ambush for opportunities to pass them.

“It comes right in, shoots its arms out [and] wraps its arms around the E-Jelly,” says Nathan Robinson at the Oceanographic Foundation in Valencia, Spain.

It appears that giant squid (Architeuthis dux) patrol the waters in search of prey, deep in the so-called twilight zone. They are also famously …

Article amended on
12 May 2021

We corrected the maximum length of giant squid

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Owl-like dinosaurs had remarkably good hearing night vision

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Fossilised Shuvuuia deserti skeleton

Mick Ellison-AMNH

A tiny bird-like dinosaur with long legs muscular, clawed arms was quite the night owl. Shuvuuia deserti lived around 75 to 81 million years ago not only had remarkable hearing, but also well-honed night vision – much better than that of other dinosaurs most modern birds.

This odd creature was first discovered in the mid-1990s, but a new analysis of its inner ear bones shows that it may have been a nocturnal hunter, like modern owls.

Jonah Choiniere at the University of the Witwatersrin South Africa his colleagues analysed 3D scans of S. deserti’s inner ear found that it had a very large lagena, a structure responsible for hearing. The larger the lagena relative to the skull, the more sensitively an animal can hear – this one was bigger than researchers had ever seen in a dinosaur.

“When we stumbled onto this structure, it just immediately prompted all these questions,” said Choiniere. He his team compared the dinosaur’s inner ear with those of more than 100 species of modern birds.

They found that the only bird with a lagena even approaching the same size as S. deserti‘s was the barn owl (Tyto alba), a nocturnal hunter with extraordinary hearing night vision. If S. deserti has such sensitive hearing, they wondered, how well could it see?

dinosaur

Viktor Radermaker

The researchers then examined 3D scans of skull fossils of S. deserti, including an eye structure called the scleral ring, which gives clues as to how well an animal can see at night. It turned out that the animal seems to have had fantastic night vision.

Most birds dinosaurs have ears eyes adapted for daytime foraging. Because the common ancestor of birds lizards was also active in the day, nocturnal traits evolved independently within these lineages. Now, S. deserti seems to indicate that nocturnal traits may have evolved independently in non-bird dinosaurs too.

“Studying the past really requires studying the present, too,” said Choiniere. “The biodiversity we see today is an extraordinary window to the lifestyles of animals from long ago.”

Journal reference: Science, DOI: 10.1126/science.abe7941

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Alien plants: The search for photosynthesis on other worlds

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Looking for signs of life in exoplanet atmospheres is fraught with uncertainty. But now that we can detect polarised light reflected directly off other worlds, we could spot unmistakable evidence of photosynthesis

Life



5 May 2021

Stuart Mcreath

PALM trees with crimson fronds sway in the breeze as waves lap at a shore warmed by an alien sun. Rock pools are lined with something kelp-like, blue lichens carpet every boulder strange flowers spring from the dunes beyond.

Astronomers are in little doubt that a plant-filled planet exists beyond our solar system, even if they aren’t entirely sure what the flora would look like. The universe isn’t short of worlds that could host life. Extrapolating from the 4000 or so exoplanets we have identified so far, NASA researchers recently estimated that there could be around 5 billion habitable planets in our galaxy alone. The challenge is to show that one of them is indeed inhabited.

A small army of astronomers are devoted to the task, scouring light that passes through alien atmospheres for hints of bacteria or plants. It is a vibrant enterprise, but at best it provides circumstantial evidence. Astronomers have long known there is a better way – that searching for light reflected off the surface of an exoplanet offers greater chances of success. “It gives you the chance to look directly for living material itself,” says William Sparks at the SETI Institute in Mountain View, California.

The problem was that it was impossible. But recent breakthroughs suggest we can finally tease out the portion of reflected light that would betray unambiguous signs of photosynthesis from other worlds. The telescopes we need are already under construction. In the meantime, the race is on to figure out just what to look for. Astronomers are now working to identify the reflected signatures of verdant vegetation on …

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The platypus: What nature’s weirdest mammal says about our origins

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Platypuses glow in UV light, produce venom lay eggs. Yet despite their oddities, their newly sequenced genome illuminates the evolution of mammals

Life



5 May 2021

Doug Gimesy/naturepl.com

WHEN news reached London of a mole-like animal with webbed feet a duck’s bill, many people thought it was a hoax. It was the late 18th century, Britain had just begun colonising Australia the strange creature had been spotted by no less a figure than David Collins, founder of New South Wales. However, when zoologist George Shaw at the British Museum examined sketches specimens of the animal, he was sceptical. “It naturally excites the idea of some deceptive preparation by artificial means,” he wrote.

Attitudes changed as more specimens arrived. In 1799, Shaw was the first to scientifically describe the creature, giving it the name Platypus anatinus, meaning “flat-footed duck”. It was later referred to as the “paradoxical bird-snout” before being officially renamed Ornithorhynchus anatinus, meaning “duck-like bird snout”. Today, most people just call it the platypus.

It took more than 80 years just to work out how this animal fits into the tree of life. Since then, biologists have gone even further found that it possesses a range of features that mean it is among the most unusual creatures on Earth. But it isn’t simply an oddity. As a mammal that shares many characteristics with birds reptiles, the platypus holds the key to unlocking some fundamental evolutionary mysteries.

Now, geneticists have mapped its entire genome are starting to understhow it came to be so strange – what it can tell us about the origins of all mammals, including us. Even today, it turns …

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