Discover, October 1, 1995

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Paleontologists have been arguing about where birds come from for more than a century. Most of them think birds are descended from small carnivorous dinosaurs, but even that is in dispute. And now a lively controversy has arisen about what happened to birds in the 145 million years after Archaeopteryx, the earliest incontestable bird, appeared. Were most birds wiped out 65 million years ago, along with the dinosaurs themselves, by the mass extinction that ended the Cretaceous Period–such that living birds are descended primarily from a small group of shorebirds that managed to survive the catastrophe?

Continue reading “The Descent of Birds” →

Discover, September 1, 1995

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Not all ecologists spend their days in the presence of nature’s majesty, contemplating redwood groves or mountain lakes or rain forest canopies. Since 1988, Stephen Heard has been peering into a gruesome little roadside attraction called the purple pitcher plant. This bog dweller is actually quite charming to look at–it has a nodding brick-red bell of a flower and purple-veined leaves that curve in on themselves to form scalloped pitchers–but what Heard is interested in are the plant’s feeding habits. The Venus flytrap screams, ‘I’m eating insects!’ says Heard, a Canadian ecologist now at the University of Iowa. The pitcher plant does not.

Continue reading “The Processing Plant” →

Discover, September 1, 1995

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No man is an island, and Maja Matari´c thinks no robot should be, either. Matari´c, a Brandeis University computer scientist, believes robots will do their best work only when they begin to work together. How do you get a herd of robots to do something without killing each other? she asks. According to Matari´c, you have to put them in societies and let them learn from one another, just as seagulls and baboons and people do. Matari´c has already made an impressive start at teaching robots social skills. She has gotten 14 robots to cooperate at once–the biggest gaggle of machines ever to socialize.

Continue reading “The Sharebots” →

Discover, August 1, 1995

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One of the most startling sights on a first trip to Africa is a common one: women carrying things on their heads. Try to carry a suitcase on your head, and you’ll probably bite your tongue in concentration and wave your arms madly for balance. But African women walk for miles with heavy jugs of water or pots of food as if they weren’t carrying anything. Energetically speaking, they aren’t: researchers have found that the women can carry enormous loads without using any extra energy. They aren’t defying any laws of physics, though; they’re being good pendulums.

Continue reading “No Skycaps Needed” →

Discover, July 31, 1995

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When Ross MacPhee walks in the woods around his house in New Jersey, he is sometimes beset by ghosts. He sees deer and groundhogs, and as a paleontologist, he can’t help thinking about what lived in North America 12,000 years ago. Sloths the size of dump trucks, teratorn birds with 25-foot wingspans, shaggy mastodons, herds of horses pursued by cheetahs, lions, or saber-toothed tiger–all in all, a bestiary that would have put the Serengeti Plain of East Africa to shame. Yet in just a few centuries, between 11,000 and 10,500 years ago, all this life disappeared. No one is sure why.

Continue reading “Carriers of extinction” →