Wild Things: Life as We Know It

Exactly how does a snake slither across the ground? Scientists long assumed that the reptile pushed against rocks and branches to move forward. But that theory lacks legs, according to a new study. After watching snakes wriggle up rough fabric surfaces or (less successfully) smooth surfaces, scientists from New York University and elsewhere say the secret is in the scales. The belly scales are oriented so that they snag on irregularities. By pushing parts of their belly down to take advantage of this friction, the snakes have enough leverage to speed ahead.

Siberian jays screech at a predator if it enters their territory. Now a researcher from Uppsala University in Sweden says the birds aren't just panicking. They use more than 25 different calls—more than any other known bird species—depending on what kind of predator (hawk or owl) is nearby, how big a risk it poses and whether birds listening nearby are kin.

Learn more about Siberian jays at the Encyclopedia of Life.

In the Caucasus Mountains, a Dutch and Russian team found a previously unknown type of plant structure. "Snow roots" weave a foot or more through the snowpack, absorbing nitrogen trapped in the snow. Corydalis conorhiza— a member of the poppy family—has normal roots as well, but its snow roots give it a head start on the brief growing season.

When did laughing begin? To find out, researchers led by the University of Portsmouth in England tickled young humans, chimps, bonobos, orangutans and gorillas. The sounds that these great apes made were so similar, the study concluded, the "origins of human laughter can be traced back at least 10 to 16 million years"—to our common ancestor.

Learn more about great apes at the Encyclopedia of Life.

Name: The domestic dog, Canis familiaris.
Looks: Guilty (e.g., avoids eye contact, drops its tail, lies down, rolls onto its back, slinks off).
Thinks: Who knows? But a dog's guilty look is a reaction not to whatever the dog did, but to its owner's scolding, according to a study by psychologist Alexandra Horowitz of Barnard College. One telltale bit of data: dogs gave the guilty look when their owners mistakenly thought the dogs had eaten a forbidden treat, even when the dogs were completely innocent. More study—a lot more—is required to establish whether dogs have a conscience.

Learn more about the domestic dog at the Encyclopedia of Life.