Science, May 11, 2001

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On certain afternoons in Uganda, bright orange butterflies with black-and-white wings gather together on small patches of low grass, sometimes in the hundreds. Such congregations are nothing unusual in the animal kingdom; normally, males convene to try to win the attention of females. But the swarms—known as leks—that Acraea encendana form are bizarre: 94% of the butterflies are females, and they jostle for the attention of the few males, who seem reluctant suitors. “You wouldn’t expect males to be surrounded by all these virgin females and not wanting to mate,” says Francis Jiggins of Cambridge University. Even more bizarre is the cause of their sexual skew: They are plagued with a strain of bacteria known as Wolbachia, which kills males but spares females.

Continue reading “Wolbachia: A Tale of Sex and Survival” →

Natural History, March 31, 2001

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When Tim Griffin and Rodger Kram set out to study how penguins walk, they didn’t expect to be impressed. Compared with long-legged ostriches striding across a plain, waddling penguins come up short. Underwater they may be able to race like torpedoes in tuxedos, but on land they are more apt to evoke laughter than to inspire respect.

Previous research on penguins seemed to back up the laughter with hard numbers. Pound for pound, a penguin on land uses twice as much energy as other animals of its size to walk a given distance. Scientists laid the blame for this expense on waddling, the (presumably) energetically costly business of the bird’s throwing its body first to one side and then to the other as it walks.

Continue reading “The Fine Art of Waddling” →

Natural History, March 31, 2001

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My wife, Grace, and I are expecting our first child in July, so I’ve had a lot on my mind recently. Most of it has been pretty mundane stuff. What’s the fastest route from our apartment to the hospital? How exactly do you swaddle a baby? But sometimes loftier thoughts invade. I think about our child as the union of two heritages. My wife’s flows back to Ireland, to County Kerry in the south and County Derry in the north. My own heritage is more farflung, encompassing Wales, England, Germany, and Hungary, as well as countries in eastern Europe that no longer exist, having been bisected and trisected by countless wars.

Continue reading ““After You, Eve”” →

Discover, January 31, 1999

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When 1998 began, East Africa should have been at its most beautiful. Normally the short rainy season ends in December, the rivers subside, and the country sparkles; farmers raise crops, animals graze, tourists go on safaris. But this year was different. The rains were heavy and long. The water spread out for miles in places in Kenya and Somalia, cutting off villages and forcing herders to crowd with their livestock onto a few patches of dry land. Things quickly turned ugly. Camels, cows, sheep, and goats all started dying of violent fevers. Soon people, too, began to get sick. Some went temporarily blind; others began bleeding uncontrollably.

Continue reading “The El Niño factor” →