The physiologist gained insight that the bats were relying on the sense of sound for navigation because when he placed closed brass tubes inside the mammals’ ears, they could not navigate the room properly and would fly into the wires.Īlthough he did not know that the bats were emitting their own sound for orientation, sound higher than he or any human would be able to hear, Spallanzani was able to conclude that the creatures were using their ears to navigate their environment. Spallanzani knew this because bells were attached to the ends of the wires. Neuweiler adds that the Italian scientist even blinded the bats by burning them with a “red-hot needle” and still they were able to avoid the wires. “When he repeated the same experiment using bats, these small mammals flew confidently around the bishop’s study, even in total darkness, managing to avoid the wires that Spallanzani had hung from the ceiling,” wrote Neuweiler. Gerald Neuweiler, in his book The Biology of Bats, describes how Spallanzani brought owls into his lab and observed that they would not fly around the room if there was no source of light. Echolocation pulses are short bursts of sound at frequencies that span from about 1,000 hertz in birds to at more than 200,000 hertz in whales. We can find several additional examples of echolocation in nature. Balint A brief history of musculoskeletal ultrasound: ‘From bats and ships to babies and hips’, Rheumatology, Volume 43, Issue 7, 1 July 2004. “The first detailed experiments that indicated that non-audible sound might exist were performed on bats by Lazzaro Spallanzani,” states D.

Ultrasound is characterized as sound waves with a frequency higher than what is audible to the human ear.

Background info about soundwaves