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” →

Discover, June 30, 1995

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For more than 150 million years, until the Cretaceous Period ended 65 million years ago, the skies of Earth were filled with flying reptiles known as pterosaurs. Yet even more than dinosaurs, their land-bound contemporaries, pterosaurs remain a mystery. Two centuries after the first pterosaur fossil was unearthed, paleontologists are still debating whether these strange beasts were more like birds, flying with slim wings and walking on the ground on two legs, or like bats, with loose, membranous wings’ that stretched from wrist to ankle and forced them to crawl on all fours when they weren’t aloft.

Continue reading “A reptile rookery” →

Discover, June 1, 1995

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When you consider the years paleontologists often spend in daily and intimate contact with their fossils, it’s not very surprising that they come to regard their long-gone animals as pets. Some work on the show dogs of the fossil world; they brag about how fast their velociraptor ran or how efficiently their saber-toothed tiger could sever a spinal cord. But when you listen to Jenny Clack talk about her pet, a fossil creature named Acanthostega that she has been working on for seven years, she sounds like the owner of a sweet, homely mongrel. It wasn’t very smart, she says. It probably spent a lot of its time sitting at the bottom of lagoons, hidden in the muck, waiting for something to come by it could eat.

Continue reading “Coming Onto the Land” →

Discover, March 1, 1995

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These are proud times for atmospheric chemists. This year is the last year that American industry will produce chlorofluorocarbons, the ozone-destroying compounds used in such things as refrigerators and insulation. The 130-nation agreement that led to the banning of CFCs, an extension of the Montreal Protocol of 1987, was triggered by the persuasive research of atmospheric chemists. Over the past few years CFC production has already withered drastically, so 1995 may also be the first year in decades that levels of atmospheric chlorine–the ingredient in CFCs that actually destroys the ozone–fall rather than rise.

Continue reading “Unintended Consequences” →