Distance perception in echolocating bats

A study examines distance perception in bats. Many bat species use echolocation–emitting sound signals and analyzing the returning echoes–to assess their distance from an object. However, it is unclear whether translating a signal-to-echo delay into distance is an innate or learned behavior. Eran Amichai and Yossi Yovel reared 11 Pipistrellus kuhlii bat pups from birth to the age of independent flight. Because sound propagates faster in helium-enriched air than in normal air, pups were reared in conditions with either normal air or helium-enriched conditions that provided 15% increased speed of sound. Pups were trained to eat from targets up to 130 cm away from their perch. Durations and intervals of bats’ calls revealed how far bats estimated their distance from targets. Pups reared with helium-enriched air underestimated target distances, as did pups reared with normal air when exposed to helium-enriched air. However, the closer pups were to targets, the more accurately they assessed target distances. The authors also trained eight wild-caught adult bats to eat from targets and exposed them to various speeds of sound, increased by up to 27%. All adult bats underestimated target distances, and accuracy did not improve with time. The findings suggest that time perception in echolocating bats is innate, and bats discern their surroundings in terms of time rather than space, according to the authors.

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Article #20-24352: “Echolocating bats rely on an innate speed-of-sound reference,” by Eran Amichai and Yossi Yovel.

MEDIA CONTACT: Eran Amichai, Dartmouth College, Hanover, NH; tel: 603-306-1631; email:

[email protected]

; Yossi Yovel, Tel Aviv University, ISRAEL; tel: +49-30-89001301; email:

[email protected]