Pye, John David (1932– )

English zoologist who has studied the way bats use echolocation, and also the use of ultrasound in other animals.

Pye was born in Mansfield, Nottinghamshire, and studied at the University College of Wales at Aberystwyth and London University. In 1973 he became professor at Queen Mary College, London.

A surprisingly large number of animals use ultrasound (which has a frequency above about 20 kHz and is inaudible to humans) – bats, whales, porpoises, dolphins, and many insects, for example. Because of the lack of detection devices, the phenomenon was not discovered until 1935.

In 1971 Pye calculated the resonant frequencies of the drops of water in fog and found that these frequencies coincided with the spectrum of frequencies used by bats for echolocation. In other words, bats cannot navigate in fog. Pye also found that ultrasound seems to be important in the social behaviour of rodents and insects.