Ever since bat sonar was discovered eighty years ago, researchers wondered whether bats learned it or inherited it. Research shows they inherited it.
The researchers conducted an experiment in which they were able to manipulate the speed of sound. They enriched the air composition with helium to increase the speed of sound, and under these conditions raised bat pups from the time of their birth, as well as adult bats. Neither the adult bats nor the bat pups were able to adjust to the new speed of sound and consistently landed in front of the target, indicating that they perceived the target as being closer – that is, they did not adjust their behavior to the higher speed of sound.
Because this occurred both in the adult bats that had learned to fly in normal environmental conditions and in the pups that learned to fly in an environment with a higher-than-normal speed of sound, the researchers concluded that the rate of the speed of sound in bats is innate – they have a constant sense of it. “Because bats need to learn to fly within a short time of their birth,” explains Prof. Yovel, “we hypothesize that an evolutionary ‘choice’ was made to be born with this knowledge in order to save time during the sensitive development period.”
Another interesting conclusion of the study is that bats do not actually calculate the distance to the target according to the speed of sound. Because they do not adjust the speed of sound encoded in their brains, it seems that they also do not translate the time it takes for the sound waves to return into units of distance. Therefore, their spatial perception is actually based on measurements of time and not distance.
Tel Aviv University, “A surprising discovery: Bats know the speed of sound from birth” at Newswise (May 5, 2021)
Most interesting. But what does the professor mean when he says, “we hypothesize that an evolutionary ‘choice’ was made to be born with this knowledge in order to save time during the sensitive development period.” So evolution is a designer that makes choices? But, as Michael Behe would ask, “How, exactly?” He can’t walk away from the problem just by putting “choice” in quotation marks.