Sneaky Slugs

ISTOCK/GETTY IMAGES

PICKY EATER: This Cratena peregrina prefers to eat creatures with full stomachs.

A type of brightly colored sea slug has a clever trick to get two meals for the price of one. Cratena peregrina is a species of nudibranch found in the Mediterranean Sea that likes to eat tiny sea creatures called hydroids. But according to scientists, C. peregrina prefers hydroids that have themselves just eaten plankton. Eating a stuffed hydroid is like getting a double helping of supper.

Researchers call the newly discovered feeding behavior kleptopredation, from the Greek word for thief. “We are now asking whether the phenomenon of kleptopredation is found in other marine species,” says Trevor Willis, a marine biologist at the University of Portsmouth in England.