Don’t look now, but this spineless sea creature may be able to count better than your toddler.
Cuttlefish need to be savvy if they want to eat. They’re always on the lookout for shrimp, fish or crabs. When a cuttlefish spots a potential victim, it shoots out two specialized, sucker-bearing tentacles and nabs it. Since these hunters have to make constant judgments about which prey are worth targeting, it would make sense for them to have advanced cognitive skills—say, the ability to count.
To find out whether this was true, Tsang-I Yang and Chuan-Chin Chiao, of Taiwan’s National Tsing Hua University, brought some Sepia pharaonis cuttlefish into the lab for a math exam. Read More
“I don’t know what you’re talking about,” said the polar bear. “Everything seems normal to me! Watch out for that puddle.”
Up in the Arctic, things are getting slushy. But some polar bears are refusing to change their ways. Instead of compromising on where they spend their time, they’re clinging to the icy habitats they’ve always loved. As those habitats keep shrinking, though, the bears will eventually find things too crowded and uncomfortable to ignore. Read More
The goblin shark is a weird deep-sea creature first discovered off the coast of Japan in 1898. It has a ghoulish appearance, thanks to jaws that can stretch well away from the rest of its head. Scientists have assumed the goblin shark uses this trick to eat—but until recently, no one had actually watched one catching prey in the wild.
In 2008 and 2011, divers working with the Japanese television broadcaster NHK managed to capture two goblin sharks (Mitsukurina owstoni). Before rereleasing the animals, they made five video recordings of the sharks striking and eating—in one case, a shark was taking a swipe at a diver’s arm. Now Kazuhiro Nakaya, of Japan’s Hokkaido University, and others have analyzed that footage frame-by-frame to try to understand how a goblin shark does its thing. Read More
Some babies are born totally useless (I’m looking at you, Homo sapiens). Others can wobble upright shortly after birth and start teetering around. And still other animals are almost frighteningly precocious.
For example, the metallic livebearer, a little golden fish native to Cuba, hatches from an egg while still inside its mother. That means the mom gives birth to live young. The more traditional fish-y way is to lay eggs. But some other fish also bear live young, including guppies and most kinds of sharks.
Metallic livebearers (Girardinus metallicus) are hunters very with precocious babies. As soon as a newborn G. metallicus swims into the world, it’s ready to murder. Read More
If you’re ever lost in a remote European forest, you might be able to get your bearings by finding a herd of roe deer. These animals like to align themselves roughly north-south, whether they’re standing still or fleeing danger.
Roe deer are small, reddish or grayish grazers common in Europe and Asia. Petr Obleser, of the Czech University of Life Sciences in Prague, and his coauthors studied the behavior of these skittish herbivores to look for evidence that they can sense the earth’s magnetic field. Read More
Most of us don’t give much thought to drops of liquid that end up outside our drinking glasses. But physicists care a lot about liquid droplets, and study their whole lifespans—from the first splash or drip to the moment a drop disappears.
Liquids that contain three different substances, though, haven’t been studied as much. Detlef Lohse, a physicist at the University of Twente in the Netherlands, and his colleagues took a deep dive into one such liquid: ouzo. Read More
The rectal exam is a delicate art to learn. Doctors perform this procedure entirely by feel, with just one finger. Students who are learning how to do such an exam have no way of showing their work to their teachers. And volunteer subjects are—unsurprisingly—rare. In the entire United Kingdom there’s only one person registered as a test subject for rectal exams, says Fernando Bello, who works on surgical computing and simulations at Imperial College London.
Rectum models made of plastic exist to help train new doctors. But these are limited in how much they feel like the real thing. That’s why Bello and his colleagues built a robotic rectum. Read More
In the mountains of Central Africa, scientists who study critically endangered gorillas have a new tool. They’ve discovered that they can learn what viruses gorillas are carrying by stealthily collecting half-chewed plants the apes leave behind.
If this sounds reminiscent of that class clown at the third-grade lunch table who would ask if you liked seafood and then say “See? Food!” and open his mouth wide to display his sloppy Joe slurry, don’t worry—mountain gorillas are vegetarians. And researchers aren’t looking inside the animals’ mouths. They decided to search gorillas’ plant scraps for viruses exactly because they don’t want to get too close. Read More
In the open ocean, it’s good to have friends. Some young fish like to buddy up with stinging jellies to stay safe from predators. Hiding under the shelter of a jellyfish’s bell, they can grow up unharmed (as long as they dodge its tentacles). These fish include some species that humans rely on for food. But in a warming ocean, that buddy system may fall apart.
Many types of fish take advantage of hop-on jelly trolleys. Ivan Nagelkerken, a marine biologist at the University of Adelaide in Australia, and his colleagues focused their new study on the fish living with one jelly in particular: the delightfully named blue blubber jellyfish, or Catostylus mosaicus. Read More
Honeybees may seem like nature’s perfect little automatons: organized, efficient, self-sacrificing. But in reality the insects are imperfect individuals. Their dance language is sloppy and imprecise. They lose self-control when they’re hungry. And, a new study has found, worker bees have distinct personalities.
Iowa State University ecologists Alexander Walton and Amy Toth explain that animals need to meet three requirements before you can say they have “personalities.” First, individuals have to behave differently from each other in a way that’s consistent over time. Second, those behavioral differences also have to show up across different contexts. Finally, there should be sets of behaviors that tend to clump together, like personality types. Read More