Bats don’t have to learn the speed of sound – they’re born knowing it

[ad_1]

A Kuhl’s pipistrelle in flight

AGAMI Photo Agency / Alamy

Bats are born knowing the speed of sound. This may not be shocking, as they rely on echolocation to find food avoid crashing into trees in the dark. But unlike birds that learn their songs, or lions that learn to hunt, bats seem to be born knowing how to echolocate.

Bats make high-pitched calls that reflect off distant objects, then they translate the time until the echo returns into some measure of distance. Depending on air temperature, sound can move faster or slower, it is a reasonable expectation that bats would accommodate for this.

To see whether bats can adjust their echolocation to accommodate changes in the speed of sound, Eran Amichai Yossi Yovel at Tel Aviv University in Israel trained eight adult Kuhl’s pipistrelle bats (Pipistrellus kuhlii) to fly to a perch within a chamber pumped full of oxygen helium. Because helium is less dense than other atmospheric gases, sound travels faster through it.

The helium interfered with the bats’ echolocation timing caused them to aim short of the perch. At first, this was expected, but the adult bats never learned to adjust.

“We were surprised by the results. Honestly, we didn’t trust them at first,” says Amichai, now at Dartmouth College in New Hampshire.

Amichai Yovel then tried the experiment with pups instead of adults. They hand-reared 11 bats, raising half of them from birth in the helium-enriched chamber. When the bats were old enough to fly, Amichai trained the pups to fly to the perch like the adults. Still, despite the environment the pups were raised in, neither group could accurately sense the distance to the perch in the helium environment.

Both experiments indicate that bats have a rigid, innate reference for the speed of sound. The team says they expect this to be the same in all bats, as the brain structures involved in echolocation are similar across species.

Because it is such a crucial part of the way the bat understands its world, Yovel says, it is possible that an innate sense of time from birth might be more beneficial than a flexible one that takes a while to learn, even if it isn’t always perfect.

Journal reference: PNAS, DOI: 10.1073/pnas.2024352118

Sign up for Wild Wild Life, a free monthly newsletter celebrating the diversity science of animals, plants Earth’s other weird wonderful inhabitants

More on these topics:

[ad_2]

Source link

Wild horses donkeys dig desert wells that boost biodiversity

[ad_1]

A donkey digging a well

E. Lundgren

Feral horses donkeys in the Sonoran desert in North America dig their own wells, inadvertently providing a water source for other animals increasing biodiversity in the area.

Erick Lundgren at Aarhus University in Denmark his colleagues monitored four separate streams in part of the Sonoran desert in Arizona. The streams are usually supplied by groundwater but dry up in the summer. The team surveyed each stream every few weeks over the summers of 2015, 2016 2018, found that horses donkeys in the area dig wells there to access the groundwater.

“It’s a very hot, dry desert you’ll get these pretty magical spots where suddenly there is surface water,” says Lundgren.

The horses donkeys dig wells up to 2 metres in depth to access water. The team saw 59 other vertebrate species at the wells, 57 of which were recorded drinking from the wells. On average, species richness was 51 per cent higher at these wells than observed in nearby dry areas during the same time periods.

“These resources are in fact used by all other animals – there was a cacophony of organisms,” says Lundgren. This included squirrels, mule deer, quails even a black bear at one point, he says.

The wells also function as germination points for plants, especially riparian pioneer trees. These horses donkeys provide a useful source of water for a range of species, which is especially important given that deserts are becoming hotter drier as a result of climate change.

Despite this find, large herbivores are often seen as threats to conservation biodiversity. “Some research from the western United States has shown that feral horses exclude native wildlife from water sources in deserts,” says Lucas Hall at California State University, Bakersfield. “The benefit they may provide by creating new water sources will likely be offset by their high populations exclusionary effects on other wildlife.”

Journal reference: Science, DOI: 10.1126/science.abd6775

Read more on biodiversity

Sign up to Wild Wild Life, a free monthly newsletter celebrating the diversity science of animals, plants Earth’s other weird wonderful inhabitants

More on these topics:

[ad_2]

Source link

Mice on opposite North American coasts evolved the same way

[ad_1]

House mice from cold environments (right) have evolved to become bigger than house mice from warm environments (left) in a few hundred years

Katya Mack

On opposite sides of North America, house mice have strikingly similar adaptations to cold climates, have independently evolved changes to genes that drive their similar behaviours hardiness.

House mice (Mus musculus domesticus) are native to Western Europe but have spread across the world thanks to their close association with humans. They arrived in the Americas more than 200 years ago have since expanded into climates quite different from their original temperate home.

To find out how these mice have adapted to new environmental conditions, Michael Nachman at the University of California, Berkeley, his team collected 50 mice from locations in western North America ranging from Arizona in the US north to Alberta, Canada. The team analysed DNA from these wild mice kept some to breed lab populations, comparing the western mice with those from a previous study on mice from eastern North America, ranging from Florida to New York.

The mice were most closely related to those that shared their side of the continent, suggesting that mice in western eastern North America had moved north independently after an initial spreading along a southern route, says Nachman.

Yet the lab-reared mice from Alberta New York were physically similar: both were bigger than southern mice made larger nests, discouraging heat loss providing insulation, respectively.

Nachman was surprised the nest style was so clearly genetically encoded after just a few hundred generations. “Even at room temperature in a comfy lab with plenty of water constant temperature plenty of food, the mice from Canada build a bigger nest than the mice from Arizona,” he says.

The western eastern mice from cold climates shared changes in 16 genes, many involved with the regulation of body temperature.

“This suggests that there’s some predictability to evolution, that some of the same genes have changed in parallel to give rise to similar traits,” says Nachman.

But the mice also showed regional adaptations – such as fur colour changes to hydration regulation genes – which may be due to differences in soil colour rainfall between west east.

It is quite rare to be able to identify possible environmental features that explain divergent genetic changes like those seen in these mice, says Kalina Davies at Queen Mary University of London.

Going forward, Nachman wants to see if the same physical genetic patterns occur in mice spanning the length of South America.

Journal reference: PLOS Genetics, DOI: 10.1371/journal.pgen.1009495

Sign up for Wild Wild Life, a free monthly newsletter celebrating the diversity science of animals, plants Earth’s other weird wonderful inhabitants

More on these topics:

[ad_2]

Source link

Female black widow spider mates with eats multiple males

[ad_1]

The mirabilis widow (Latrodectus mirabilis)

Ken Jones/University of Toronto at Scarborough

A South American black widow spider starts biting, wrapping up eating her willing partner before they have finished mating – then mates with (eats) another male.

“Usually there are some advantages to the male for being eaten during mating, like longer copulations as well as decreased female receptivity to future males,” says Luciana Baruffaldi at the University of Toronto, Scarborough, Canada. “In this case, though, we don’t yet know how the male benefits from sexual cannibalism.”

Despite a reputation for eating their mates, …

[ad_2]

Source link

Billion-year-old microbe had taken first step towards internal organs

[ad_1]

When multicellular organisms grow, their cells can begin differentiating to form internal structures

bennu phoenix/Alamy

A tiny organism that lived a billion years ago had two different cell types, one forming its core another its outer “skin”. It may have been one of the first life forms built that way, making it a crucial step towards modern organisms like animals that also have a skin that is distinct from the cells inside the body.

“This fossil clearly is multicellular with two different types of cell,” says Charles Wellman at the University of …

[ad_2]

Source link

1 234 235 236 237 238