Bats can differ from each other on the basis of their individual sonar calls. Photo: Manuel Werner
Reading Bats can differ from each other in their beeping as people do in their voices. Researchers from Tübingen and Konstanz have found this out in tests with large mouse ears. After two to three weeks of training, the animals were able to hear the individual echosounding calls of a conspecific from the calls of other animals with more than 75% certainty. Yossi Yovel and Mariana Melcon from the University of Tübingen and their colleagues report on their results. The sonar calls, which are inaudible to humans, serve as orientation for bats: they can use the sound signals reflected from obstacles such as trees or rock walls to form a very precise picture of their surroundings even in complete darkness. In these sonar calls, researchers had long since demonstrated individual sound patterns. The fact that the bats actually use them to differentiate their fellow members within their social association, the German researchers could now prove in their experiments.

The scientists first made sound recordings of five male animals flying around in a soundproofed room. Each of the animals had to distinguish in the following training between the calls of two different conspecifics whose calls the researchers played to him. If the bats were correct in their selection, they were rewarded with a mealworm. The animals were successful in this training phase in three out of four cases, the researchers played in further tests before the calls of a known animal and recordings of completely unknown individuals. Here, the researchers were able to observe in the animals the ability to clearly distinguish between known animals and unknown conspecifics.

The researchers also simulated the ability to differentiate between individuals in a computer model and deduced how the animals would behave in real life. The results matched well with the observations. The scientists conclude that the animals can learn typical characteristics of these echo sounding calls and thus distinguish individual individuals.

Yossi Yovel (University of Tübingen) et al .: PLOS Computational Biology, doi: 10.1371 / journal.pcbi.1000400 ddp / science.de? Ulrich Dewald ad

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