Photo of the Day 32

Slug Caterpillar, Manu River, Peru, 2001

Photograph by George Grall

Brushlike suckers radiate from the body of a slug caterpillar resting on a leaf near Peru's Manu River. The stinging hairs, or suckers, of these brightly colored, fleshy caterpillars contain mildly venomous toxins used for defense purposes. However, simply touching a slug caterpillar triggers toxin transfer, which causes rashes, swelling, and in some cases, fever and nausea.

(Photo shot on assignment for, but not published in, "The Fragile World of Frogs," May 2001, National Geographic magazine)