Cultural Transmission In Bats: When Listening For Dinner, Bats Learn From Their Neighbors

While numerous examples are known of instances where predators can use so-called "social learning" to learn new visual and olfactory cues associated with prey, this kind of learning of an acoustic cue had not been previously described. The work is reported by Rachel A. Page and Michael J. Ryan of the University of Texas at Austin and the Smithsonian Tropical Research Institute and appears in the June 20th issue of Current Biology.

The fringe-lipped bat, Trachops cirrhosus, uses frog calls from different species as acoustic cues to assess the palatability of its prey. Previous experiments have shown that T. cirrhosus is extremely flexible in its foraging behavior.

In the new study, Page and Ryan investigated the role of social learning in bat foraging flexibility. Comparing three different learning groups, the researchers measured the rate at which bats learned new foraging information: in this case, the novel (experimental) association of the calls of a poisonous toad species with the presence of palatable prey.

The researchers tested the effectiveness of learning this experimental association through three different means: (a) a social learning group, in which a bat inexperienced with the new call-food association was allowed to observe an experienced bat; (b) a social facilitation group, in which two inexperienced bats were presented with the experimental task together; and (c) a trial-and-error group, in which a single inexperienced bat was presented with the experimental task alone.

In the social learning group, bats rapidly acquired the novel association in an average of 5.3 trials. In the social facilitation and trial-and-error groups, most bats did not approach the call of the poisonous species even after 100 trials. These results suggest that once acquired, novel prey-cue/prey-quality associations could spread rapidly through bat populations by cultural transmission.

The researchers include Rachel A. Page and Michael J. Ryan of the University of Texas at Austin in Austin, TX and the Smithsonian Tropical Research Institute in Balboa, Panama.

Funding was provided to R.A.P by a National Science Foundation Graduate Research Fellowship and the Theodore Roosevelt Memorial Fund of the American Museum of Natural History.

Page et al.: "Social Transmission of Novel Foraging Behavior in Bats: Frog Calls and Their Referents." Publishing in Current Biology 16, 1201–1205, June 20, 2006, DOI 10.1016/j.cub.2006.04.038. www.current-biology.com