Female Frogs Know How to Tell Males to Buzz Off

How to put this delicately. "Black-spotted male frogs will jump on anything that looks like a female, including nonorganic objects," says Japanese researcher Makato M. Itoh of Nagoya University. But the females, it appears, have developed a simple way to ward off males looking to mate if they are not so inclined, per a new study in the journal Behavioral Processes. They do so by emitting a certain croak—and the males listen and stay away. The reason? "The sound may be an 'honest' signal that she isn't fertile and mating would be a waste of the male's sperm and energy," explains New Scientist.

In general, males do most of the croaking to indicate they are looking to procreate, and they often force females to mate with them—"sexual coercion" is the term researchers use. However, Itoh's team noticed that female frogs emit "simpler, shorter, and less intense sounds" amid the male cacophony, per Hungary Posts. It appears to be a signal to the males that an encounter would be fruitless, biologically speaking. "The results of this study revealed that females without eggs which were assumed to finish spawning emitted calls in response to male approaches, and the males subsequently moved away from the females obediently," per the study. All of which suggests frog vocalizations are far more complicated than has been long assumed. (More frogs stories.)