Eran Amichai, Yossi Yovel. Echolocating bats rely on an innate speed-of-sound reference. Proceedings of the National Academy of Sciences May 2021, 118 (19) e2024352118; DOI: 10.1073/pnas.2024352118

Abstract
“Animals must encode fundamental physical relationships in their brains. A heron plunging its head underwater to skewer a fish must correct for light refraction, an archerfish shooting down an insect must “consider” gravity, and an echolocating bat that is attacking prey must account for the speed of sound in order to assess its distance. Do animals learn these relations or are they encoded innately and can they adjust them as adults are all open questions. We addressed this question by shifting the speed of sound and assessing the sensory behavior of a bat species that naturally experiences different speeds of sound. We found that both newborn pups and adults are unable to adjust to this shift, suggesting that the speed of sound is innately encoded in the bat brain. Moreover, our results suggest that bats encode the world in terms of time and do not translate time into distance. Our results shed light on the evolution of innate and flexible sensory perception.”

Significance
“Animals rely on their senses to survive and reproduce. Sensory systems are subject to a trade-off between the advantage of flexibility that often comes with a cost of a prolonged learning period and the advantage of innateness, which is less successful in dealing with altered environments. Most bat species rely on echolocation—emitting sound signals and analyzing the returning echoes. An object’s distance can be assessed using echolocation given a reference to the speed of sound. Since bats experience a range of speeds of sound, we tested whether the encoding of the speed of sound is innate or learned. We found that bats’ reference to the speed of sound is innate and that it is not flexible during adulthood.”

Eran Amichai, Yossi Yovel. Echolocating bats rely on an innate speed-of-sound reference. Proceedings of the National Academy of Sciences May 2021, 118 (19) e2024352118; DOI: 10.1073/pnas.2024352118