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Rebecca Lai via Flickr Creative Commons // CC BY 2.0
Rebecca Lai via Flickr Creative Commons // CC BY 2.0

Rats Use Their Whiskers to Follow the Wind

Rebecca Lai via Flickr Creative Commons // CC BY 2.0
Rebecca Lai via Flickr Creative Commons // CC BY 2.0

We humans have all kinds of ways to determine which way the wind is blowing. We could consult a weathervane, or hold out a freshly-licked finger, or watch which way the inconsiderate gusts fling our freshly-brushed hair. To the best of our knowledge, other mammals don’t use any of these techniques. Exactly how they do it has been something of a mystery—until now. Researchers say that rats (and most likely other mammals as well) sense air and wind direction through their whiskers. They published their findings in the journal Science Advances.

The act of following the wind is called anemotaxis, after the Greek Anemoi, or wind gods. Most of what we know about anemotaxis pertains to flying insects, which have elevated wind-surfing into an art form. And while land mammals may not be riding the currents, they do rely on air currents to evade predators, find mates, and locate food.

To figure out how the animals do it, researchers at Northwestern University designed a circular arena for lab rats. On one side of the circle were five fans, and in front of each fan was the entrance to a small tunnel. At the end of the tunnel was a reward. The scientists turned on the fans at random, one per round, and trained the rats to run to the tunnel directly in front of whichever fan was blowing. At first, the rats were allowed to use all of their senses to sort out the source of the wind, from the ruffling of their fur in the breeze to the sound of the fan itself.

After 10 consecutive days of testing, the rats were able to pass the test approximately 60 percent of the time. The researchers then trimmed the rats’ whiskers, leaving all their other senses intact. With no whiskers, the rats’ success rate dropped by 20 percent.

The researchers say that the fact that they were still able to find the fan sometimes suggests that they rely on multiple forms of sensory input. "The rat clearly uses more than one cue," co-author and neuroscientist Chris Bresee said in a statement. "But rats still choose to rely heavily on their whiskers, which suggests that whiskers facilitate wind-sensing even when wild rats explore naturally."

Previous studies from the same research team have shown that rats’ whiskers bend in the same direction as the wind. The harder the wind blows, the more they bend.

Although this study included only rats, the researchers note that the whiskers of cats, dogs, and other mammals are arranged quite similarly. "It would make sense for all sorts of animals to exploit this mechanical information, given that sensing wind direction is important for so many behaviors," said co-first author Yan Yu.

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NOAA, Wikimedia Commons // Public Domain
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Watch the First-Ever Footage of a Baby Dumbo Octopus
NOAA, Wikimedia Commons // Public Domain
NOAA, Wikimedia Commons // Public Domain

Dumbo octopuses are named for the elephant-ear-like fins they use to navigate the deep sea, but until recently, when and how they developed those floppy appendages were a mystery. Now, for the first time, researchers have caught a newborn Dumbo octopus on tape. As reported in the journal Current Biology, they discovered that the creatures are equipped with the fins from the moment they hatch.

Study co-author Tim Shank, a researcher at the Woods Hole Oceanographic Institution in Massachusetts, spotted the octopus in 2005. During a research expedition in the North Atlantic, one of the remotely operated vehicles he was working with collected several coral branches with something strange attached to them. It looked like a bunch of sandy-colored golf balls at first, but then he realized it was an egg sac.

He and his fellow researchers eventually classified the hatchling that emerged as a member of the genus Grimpoteuthis. In other words, it was a Dumbo octopus, though they couldn't determine the exact species. But you wouldn't need a biology degree to spot its resemblance to Disney's famous elephant, as you can see in the video below.

The octopus hatched with a set of functional fins that allowed it to swim around and hunt right away, and an MRI scan revealed fully-developed internal organs and a complex nervous system. As the researchers wrote in their study, Dumbo octopuses enter the world as "competent juveniles" ready to jump straight into adult life.

Grimpoteuthis spends its life in the deep ocean, which makes it difficult to study. Scientists hope the newly-reported findings will make it easier to identify Grimpoteuthis eggs and hatchlings for future research.

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10 Things You Might Not Know About Grizzly Bears
Joe Raedle, Getty Images
Joe Raedle, Getty Images

Ursus arctos horribilis is better known by the more casual term of grizzly bear. These massive, brown-haired predators have a reputation as one of nature’s most formidable killing machines. Standing up to 8 feet tall and weighing 800 pounds, these fierce mammals have captivated—and frightened—humans for centuries. Keep your distance and read up on these facts about their love for munching moths, eating smaller bears, and being polar-curious.

1. THEY’RE ACTUALLY PRETTY LIGHT EATERS.

Grizzlies—more accurately, North American brown bears—are strong enough to make a meal out of whatever they like, including moose, elk, and bison. Despite their reputation for having carnivorous appetites, their diet also consists of nuts, berries, fruits, and leaves. They’ll even eat mice. The gluttony doesn’t kick in until they begin to exhibit hyperphagia, preparing for winter hibernation by chomping down enough food to gain up to three pounds a day.

2. THEY USE “CPR” TO GET AT YOUR FOOD.

A grizzly bear eats fruit in Madrid, Spain
Dani Pozo, AFP/Getty Images

More than 700 grizzlies live in or near Yellowstone National Park, which forces officials to constantly monitor how park visitors and the bears can peacefully co-exist. Because bears rummaging in food containers can lead to unwanted encounters, the park’s Grizzly & Wolf Discovery Center tests trash cans and coolers to see if they’re bear-resistant. (Nothing is truly bear-proof.) Often, a bear will use “CPR,” or jumping on a canister with its front legs, in order to make the lid pop off. Containers that can last at least 60 minutes before being opened can be advertised by their manufacturers as being appropriate for bear-inhabited environments.

3. THEY CAN CLIMB TREES.

It's a myth that grizzlies can't climb trees. Though their weight and long claws make climbing difficult [PDF], and they need support from evenly-spaced branches, grizzlies can travel vertically if they choose to.

4. THEY’LL EAT OTHER BEARS.

Two grizzly bears play in a pool at a zoo in France
Jean-Francois Monier, AFP/Getty Images

In addition to being omnivorous, grizzlies can also be classified as cannibals. They’ve been spotted eating the carcasses of black bears in Canada. Calling it a “bear-eat-bear world,” officials at Banff National Park in Alberta said the grizzlies are “opportunistic” and more than willing to devour black bears—sometimes just one-fifth their size—if the occasion calls for it. And it’s not just black bears: One study on bear eating habits published in 2017 recorded a 10-year-old male eating a 6-year-old female brown bear.

5. THEY LOVE MOTHS.

Although grizzlies enjoy eating many insects, moths are at the top of the menu. Researchers have observed that bears are willing to climb to alpine heights at Montana’s Glacier National Park in order to feast on the flying appetizers. Grizzlies will turn over rocks and spend up to 14 hours in a day devouring in excess of 40,000 moths.

6. A PAIR OF THEM ONCE LIVED ON WHITE HOUSE GROUNDS.

A grizzly bear appears at the Wild Animal Sanctuary in Keenseburg, Colorado
John Moore, Getty Images

In what would be considered an ill-advised decision, explorer Zebulon Pike decided to gift his friend President Thomas Jefferson with two grizzly cubs in 1807. Jefferson reluctantly accepted them and kept them in a cage near the north entrance to the White House, and later re-gifted the cubs to museum operator Charles Willson Peale. Sadly, one of them got shot after getting too aggressive with Peale’s family.

7. THEY CAN RUN FASTER THAN USAIN BOLT.

The bears we see in fiction or lazing about in the wild tend to look cumbersome and slow, as most anything weighing nearly a half-ton would. But in a land race, even Olympic champions would be on the losing end. Grizzlies can reportedly run 35 mph, and sustain speeds of up to 28 mph for two miles, faster than Usain Bolt’s 27.78 miles per hour stride (which he can only sustain for a few seconds).

8. THEY MATE WITH POLAR BEARS.

A grizzly bear is shown swimming at a pool in an Illinois zoo
Scott Olson, Getty Images

In parts of Alaska and Canada where grizzlies and polar bears converge, there are sometimes rare sightings of what observers call “grolar bears” or “pizzlies.” With large heads and light-colored fur, they’re a hybrid superbear birthed from some interspecies mating. Typically, it’s male grizzlies who roam into those territories, finding female polar bears to cozy up with. Researchers believe climate change is one reason the two are getting together.

9. THEY KNOW HOW TO COVER THEIR TRACKS.

When it comes to intellect, grizzlies may not get all the same publicity that birds and whales do, but they’re still pretty clever. The bears can remember hotspots for food even if it’s been 10 years since they last visited the area; some have been observed covering tracks or obscuring themselves with rocks and trees to avoid detection by hunters.

10. THEY’RE NOT OUT OF THE WOODS YET.

A grizzly bear and her cub walk in Yellowstone National Park
Karen Bleier, AFP/Getty Images

For 42 years, grizzlies at Yellowstone occupied the endangered species list. That ended in 2017, when the U.S. Fish and Wildlife Service declared that a rise in numbers—from 150 in the 1970s to more than 700 today—meant that conservation efforts had been successful. But overall, the grizzly population is still struggling: Fewer than 2000 remain in the lower 48 states, down from 50,000 two centuries ago.

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