Music to His Ears

National Wildlife, August, 1998

Throughout the animal kingdom, males almost always take the initiative in courtship. The usual model involves a zealous male courting a choosy female. That is especially true of creatures that advertise their availability with song, such as birds, whales, frogs and many species of insects. So researchers were surprised recently to discover that not only does the female South African clawed frog take a leading role in mating matters, she does so by producing her own percussion music.

Mating takes place at night in murky ponds crammed with frogs of both sexes. Once the female's eggs are ready to receive sperm, she has only about 24 hours to attract a suitor. Males do vocalize to generally announce their presence, but then they wait passively for further developments. A female looking for a mate swims to a vocalizing male and generates a series of loud clicks that sound something like a Geiger counter detecting radiation. A responding male then emits his own answer trill, and mating follows.

When biologists Darcy Kelley and Martha Tobias at Columbia University in New York conducted experiments with the frogs, one male was so attracted by a broadcast of the female's song that he tried to mate with the loudspeaker. "One could think of the female's advertisement call as a general love song and the male's answer call as a serenade to a specific love object," says Kelley.