Donald Redfield Griffin: the discovery of echolocation

Abstract

The puzzle as to how bats navigate without colliding with obstacles and hunt tiny mosquitoes in complete darkness remained unanswered for nearly 140 years after Lazzaro Spallanzani, who proposed at the close of the 18th century that bats possess a 'sixth sense' for orientation. Donald Griffin solved the puzzle in 1938 with the help of world's first ultrasound microphone devised by the American physicist G W Pierce. Griffin called this sixth sense 'echolocation', which enables bats and marine mammals such as whales, dolphins and porpoises to lead active lives under the cover of darkness. In this article we describe the life of Donald Griffin and how he proved the existence of echolocation in bats.