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.

动物必须在大脑中编码基本的物理关系。一只苍鹭将头伸入水下串鱼必须校正光线折射，射箭鱼击落昆虫必须“考虑”重力，而攻击猎物的回声定位蝙蝠必须考虑声速以评估其距离。动物是否会学习这些关系，或者它们是天生的编码，它们是否可以在成年后调整它们都是开放性问题。我们通过改变声速和评估自然体验不同声速的蝙蝠物种的感官行为来解决这个问题。我们发现新生的幼崽和成年人都无法适应这种转变，这表明声音的速度是在蝙蝠大脑中天生编码的。而且，我们的结果表明，蝙蝠根据时间对世界进行编码，并且不会将时间转化为距离。我们的结果阐明了先天和灵活的感官知觉的演变。