Wild Things: Life as We Know It

Caterpillars appear to walk in a wavelike motion that starts with their back legs and moves forward. But to the surprise of scientists from Tufts University and elsewhere, the insect gets going when it suddenly thrusts its innards forward; the rest of its body, 16 legs included, catches up like the end of a slinky. The scientists learned this from X-rays of hawkmoth caterpillars in action. They suggest that a similar mechanism—“gut sliding,” they call it—propels other caterpillars. It’s “unlike any form of legged locomotion previously recorded.”

Imagine a creature the size of Big Bird, but with a sharp beak and a less sunny disposition. Such “terror birds” stood up to seven feet tall and roamed South America for more than 50 million years, until they became extinct a few million years ago. Studying the 15-inch-long skull of the mid-size Andalgalornis, scientists from Argentina’s National University of La Plata and elsewhere say the fowl wielded its hooked beak like a pickax, hacking away at its prey.

Male blue whales off the coast of California sing a drawn-out note pitched four octaves below middle C. San Francisco State University scientists now say such a singing whale may be relying on the phenomenon called the Doppler effect to inform others, especially females, of its location. If other whales perceive the tone as rising, they know they’re moving closer to the source; if the pitch seems to be falling, they know they’re moving away.

Invasive species can harm native species by commandeering food or habitat. Washington University researchers have now documented a less familiar type of threat on the dunes of Point Reyes National Seashore in California. An invasive beach grass spreading along the coast is helping to destroy an endangered native plant called Tidestrom’s lupine by providing new shelter for mice, which feast on the lupine seeds.

Name: Leiopelmatidae, a family of primitive frogs native to New Zealand.
Leap: By extending their hind legs, like other frogs.
Land: On their bellies—unlike frogs that evolved more recently, which land on four feet to absorb the shock.
Lesson: If a group of primitive frogs belly-flops, it suggests that the common ancestor of all frogs did as well. In other words, “frogs evolved jumping before they perfected landing,” according to the study by Richard Essner of Southern Illinois University and others. As for Leiopelmatidae, he says, “these guys are small, so bad landings aren’t as big of a deal.”