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The capability to seek out medicinal plants was thought to be limited to creatures with advanced brains; for instance, chimpanzees harboring intestinal worms swallow bristly leaves to scrape the parasites from their guts. Now researchers at Wesleyan University and their colleagues fi nd that woolly bear cater-pillars (Grammia incorrupta) also self-med-icate when ill. Caterpillars infested with par-asitic fl y maggots ate roughly twice as much alkaloid (specifi cally, pyrrolizidine alkaloid) as uninfested ones; such toxins naturally ex-ist in bloodroot and other caterpillar food plants. As a result, roughly 20 percent more of the infested caterpillars survived into adulthood as compared with infested cater-pillars that did not munch on the medicine. The fi ndings, the fi rst known instance of in-vertebrate self-medication, appear in the March 10 PLoS ONE. —Charles Q. Choi

BIOLOGY

Bug OffA rock-throwing chimp at Sweden’s Furuvik Zoo proves that nonhuman primates can plan for the future. For the past several years, Santino has put on a show of dominance every day at around 11 A.M. by yelling and running around, which is typical of male

chimps. But he would occasional-ly lob rocks at zoo visitors. (For-tunately, his aim is terrible, and no one has been seriously hurt.) Workers found that earlier in the morning he would calmly fi sh his ammunition out of the moat around his habitat and chip away at concrete rocks on his island to form dessert-plate-size disks. San-tino would then pile up his weap-ons. This observation, described in the March 10 Current Biology,confi rms lab experiments show-ing that our fellow apes can pre-pare for upcoming events.

—Coco Ballantyne

BEHAVIOR

Planning of the Apes

AND MY NEXT TARGET IS. . . : At least it’s only rocks that Santino likes to fl ing at zoo visitors.