California Sister Adelpha californica

The dramatic cream-white band across its dark wings inspired the common name — resembling a nun's white habit. But there's nothing passive about this butterfly. It is chemically defended and unpalatable to predators, and its wing pattern is shared by several other species in the same habitat, forming a mimicry complex where everyone benefits from being recognized as bad-tasting. Adults have the unusual habit of feeding on tree sap, rotting fruit, and animal dung rather than flowers.

Caterpillars are expert camoufleurs, resting along leaf midribs and incorporating their own frass into a silken structure that makes them nearly invisible to searching predators. In California's oak woodlands, this butterfly is a common sight — but its defenses are anything but ordinary.