A new study from Tel Aviv University has found, for the first time, that bats know the speed of sound from birth. To prove this, the researchers bred bats from birth in a helium-enriched environment in which the speed of sound is faster than normal. They discovered that unlike humans, who map the world in units of distance, bats map the world in units of time. This means that the bat perceives an insect as being at a distance of nine milliseconds, and not one and a half meters, as previously thought.
The study was published in the Proceedings of the National Academy of Sciences.
In order to determine where objects are in a space, bats use sonar – they produce sound waves that strike objects and are reflected back to the bat. Bats can estimate the position of the object based on the time that elapses between when the sound wave is produced and when it is returned to the bat. This calculation depends on the speed of sound, which can vary under different environmental conditions, such as air composition or temperature. For example, there could be a difference of almost 10% between the speed of sound in the height of summer, when the air is warm and sound waves travel faster, and the winter season. Since the discovery of sonar in bats 80 years ago, researchers have been trying to determine whether bats acquire the ability to measure the speed of sound during their lifetimes or are born with this innate and constant sense.
Now, researchers led by Professor Yossi Yovel, head of the Sagol School of Neuroscience and faculty member of the School of Zoology at the Faculty of Life Sciences and his former doctoral student, Dr Eran Amichai (currently a student at Dartmouth College) were successful in answering this question. The researchers conducted an experiment in which they were able to manipulate the speed of sound. They enriched the composition of the air with helium to increase the speed of sound and, under these conditions, bred bat puppies from birth, as well as adult bats. Neither adult bats nor puppies were able to adjust to the new speed of sound and consistently landed in front of the target, indicating that they perceived the target to be closer – that is, ‘they did not adjust their behavior to the highest. speed of sound.
Because it happened both in adult bats that had learned to fly under normal environmental conditions and in puppies that learned to fly in an environment with a higher-than-normal speed of sound, the researchers concluded that the rate of sound speed in bats is innate – they have a constant sense of it. “Because bats need to learn to fly soon after 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 finding from the study is that bats don’t actually calculate target distance based on the speed of sound. Because they don’t adjust the speed of the sound encoded in their brain, they also don’t seem to translate the time it takes for sound waves to come back in units of distance. Therefore, their spatial perception is actually based on measurements of time and not distance.
Teacher. Yossi Yovel: “What excited me the most about this study was that we were able to answer a very basic question – we found that in fact bats do not measure distance, but rather distance. time, to orient themselves in space, as a semantic difference, but I think that means their spatial perception is fundamentally different from that of humans and other visual creatures, at least when they rely on sonar. is fascinating to see how diverse the evolution is in the strategies of cerebral computation. product. “
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Material provided by Tel Aviv University. Note: Content can be changed for style and length.