Bats were adaptable to hunt in the urban noise

Dutch biologists have discovered that at least one species of bats is able to adapt to the use of sonar in a high noise pollution. The results are presented in the journal Science.

The basic tool orientation, and especially hunting bats is ultrasonic echolocation. With it, animals emit sounds inaudible to humans and capture them echo reflected from the surrounding objects. Contrary to popular belief, bats are not blind, carnivorous species have keen eyesight, and some, in particular big Myotis (Myotis myotis), are sensitive to the polarization of light: it allows them to determine the direction of the solar radiation at sunrise and sunset.

In the new study, the researchers analyzed the effectiveness of echolocation of bats in a high background noise. For this twelve bahromchatogubyh leaf-nosed bat (Trachops cirrhosus) was placed in a cage with a robotic toy frogs - leaf-nosed bat in the wild seek out for tree frogs mating cries. Each toy has a tube connected to the compressed air, which also allows the author at the right time to simulate the swelling of throat sac amphibians.

During the experiment, the team activated the horn throat and swelling of the bag "frogs" in random order. At this stage the extraction bats attacked irrespective of stimulus. To maintain interest bats scientists regularly placed in a cage pieces of fish. The authors then reproduced using the speakers artificial continuous noise. As a result, the animals doubled the intensity of the emitted ultrasound and often attacked the toys to which compressed air is supplied.


According to co-author Wouter Halfverka, such tactics say that as a compensatory mechanism bats employ echolocation additional resources. The ability to adapt the strategy of behavior and, in particular, hunting helps explain why certain types of animals are better adapted to living near cities and roads. Similarly arrives and a man: being in a noisy environment, it pays more attention to the movement of the lips interlocutor than usual, the scientist said.