The Japanese Tree Frog’s Call

Male Japanese tree frogs are well-known for their repetitious and seemingly random calls. Yet, individual males can be identified even when there is a noisy group of them. In Japan, researchers studying the frogs have discovered that the secret lies in the highly coordinated way that males in the same area make calls to females.

Consider: Male Japanese tree frogs produce sound in order to attract females. The sound originates with the animal’s vocal cords and is amplified as it resonates in the vocal sac, an inflatable pouch on the throat.

How can the calls of one male be distinguished from those of other males? Researchers have found that instead of calling randomly, neighboring Japanese tree frogs call in sequence, each frog taking its turn. This efficient technique avoids acoustic overlap, thus producing a clear chorus of individual sounds while at the same time saving energy. Additionally, by coordinating their calls, the frogs are able to pause between choruses.

Inspired by the way the calls of Japanese tree frogs are coordinated, researchers in wireless communications are using sophisticated mathematics in an effort to improve the timing of data transmission so that packets of data do not interfere with one another. The results include more reliable data transmission and reduced power consumption.

What do you think? Did the ability of Japanese tree frogs to create a chorus of coordinated calls evolve? Or was it designed?