Wild Things: Feathered dinosaurs, king crabs and spotted hyenas

King crabs have come to the Antarctic shelf. Frigid water kept them away for millions of years, but now the region is warming up, says Craig Smith of the University of Hawaii, who observed the invaders via robotic submarine. The crabs crush sea cucumbers, sea lilies and brittle stars—fragile creatures that have little resistance to clawed predators. The scientists captured one crab: a female laden with eggs.

Most of what we know about dinosaurs comes from their fossils. But a University of Alberta research team recently found a different kind of evidence: 11 feathers preserved in amber. The feathers were encased in tree resin about 80 million years ago. The amber pieces were collected from a deposit in Alberta, most in the mid-1990s, and stored in the Royal Tyrrell Museum until grad student Ryan McKellar recently analyzed them. Many dinosaurs, including the ancestors of modern birds, were feathered. It’s not clear which species left these, but some closely resemble fossilized impressions of dinosaur feathers. They range in color from pale to dark brown, and some appear specialized for flying or underwater diving. But they don’t preserve DNA suitable for cloning.

To reproduce, the parasite Toxoplasma gondii needs to get from a rat into a cat. It’s known that infected rats don’t fear the scent of cat urine. New research led by Stanford University adds to the bizarre tale: When infected male rats smell cats, the brain region that responds to female rats is activated. That is: The rats are attracted to cats.

When Central America rose from the ocean three million years ago, horn snails divided into two species, one in the Pacific and one in the Atlantic. Smithsonian Tropical Research Institute scientists and others collected snails from 29 locations to study genetic variation. They found that twice, 750,000 years ago and 72,000 years ago, the marine snails crossed the isthmus. How? They likely flew, hitching a ride on birds’ legs.

Heeds: The whoops of intruding hyenas when they are played through loudspeakers in the wild, at least in a study by Michigan State University researchers.
Counts: The number of hyenas on the recording, according to the study, which is the first to show that hyenas can distinguish one intruder’s whoop from another’s.
Calculates: Its odds before approaching the intruders or fleeing. “They’re more cautious when they’re outnumbered and take more risks when they have the numerical advantage,” says Sarah Benson-Amram. Hyenas join lions and chimpanzees as animals that demonstrate the ability to compare their own to their opponents’ numbers.