During a bullfrog chorus, males pay attention to calls from around a pond but are more likely to answer their most distant neighbors.

This first rule of bullfrog calling behavior comes from a new study of the animals. It adds to a growing body of evidence that certain rules or strategies, which are to some extent both competitive and cooperative, govern the calling behavior of frogs.

The study suggests that calling by male bullfrogs may be elicited by calls of distant neighbors, or even inhibited by calls of neighbors close by, said lead investigator Susan Boatright-Horowitz, assistant professor of psychology at the University of Rhode Island. This rule-driven strategy enables male bullfrogs to call and attract females and maintain territories, yet conserve energy, she said.

Conducted in Rhode Island wetlands, the study was published in the journal Ethology last August.

Male bullfrogs use advertisement calls to get females to cross a pond to breed. By homing in on calls, female bullfrogs will travel significant distances to find males. Calling is physically draining, requiring more energy than any other activity of a male bullfrog. In addition, calling clues predators, such as raccoons or turtles, to a frogs location.

During a chorus of male bullfrogs, individual males will keep track of who calls, said co-author Andrea Simmons, professor of psychology and neuroscience at Brown. The study suggests that males form stable territories, and may recognize their neighbors, either by acoustic or spatial knowledge of their environment.

A male must keep track of females and other males in the area, but it also doesnt need to put itself at any further risk from compet
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Contact: Scott Turner
Scott_Turner@Brown.edu
401-863-1862
Brown University
1-Nov-2000