Poisonous Frog? Sounds Delicious

Biologists find that bats learn behavior from one another

• Hannah Schardt
• Oct 01, 2006

LIKE MOST OF US, frog-eating fringe-lipped bats have strong food preferences. The bats, which live in Central America and South America, react to the call of a tungara frog as if it were a dinner bell, yet they ignore the call of a poisonous cane toad. But a new study indicates that those preferences can be changed with a little help from their friends.

University of Texas–Austin researcher Rachel Page temporarily placed wild bats in a large outdoor cage along with "tutor" bats--animals that had been trained to associate a poisonous toad's call with edible prey. She then played recordings of those toad calls--sounds that the bats would ordinarily ignore--and watched what happened when the "naïve" bats observed tutor bats responding to the calls and receiving food rewards.

Page had previously observed the animals' extraordinary trainability with the tutor bats, so she expected that they would eventually learn by watching other bats. But she wasn't prepared for how quickly the change occurred: on average, after only five trials. "Some even learned after a single trial," says Page.

Page says that this adaptability, which she suspects is a reaction to the chaotic, crowded nature of the rain forest, has "interesting conservation implications." Researchers are eager to know how highly specialized predators that feed on animals facing extinction, including many tropical frogs, will react to dramatic changes in prey abundance. And as for those bats that were trained to associate the calls of inedible frogs with dinner? Not to worry: "At the end, we took three days to reverse them back before releasing them," says Page.