Bats are known for their impressive echolocation skills that they use to locate objects and directions to avoid colliding with them. It also permits the bats to calculate the three-dimensional location of small and big objects from the echoes that bounce back from the object like frequency, spectrum, and intensity.
However, there are instances when bats collide with smooth surfaces like glass. Smooth surfaces act as an acoustic mirror that reflects most of the soundwaves away from the bats and only realizes the presence of the glass when they are already near it.
Furthermore, a new study from Tel Aviv University (TAU) has found why bats still collide with walls when they fly even if they can detect it with their sonar system. They concluded that it has nothing to do with their sensory limitation but with something else.
An Error to The Acoustic Perception of Bats
Science Daily reported that bats hit the wall because of an error in their acoustic perception. The study, published in PNAS on October 26, involved dozens of bats released in a corridor blocked by objects of different sizes made from different materials.
The researchers discovered that the bats collided with large sponge walls that produce a weak echo, which makes it hard for bats to locate. Based on the bats' behavior, the researchers think that the bats were able to detect the walls with their sonar system; however, they hit the wall due to acoustic misperception.
The team of scientists believes that the combination of a large wall and a weak echo has disrupted the bats' sensory perceptions, which caused them to ignore it and therefore hit the wall. Besides, they also discovered that acoustic perception is not an inborn skill, but rather it is acquired.
The Correlation Between The Size of The Object And Echo
Like how humans or other animals could ignore the transparent walls, the researchers hypothesize that the combination of large walls and weak echo is why the bats hit the wall.
The researchers then tried to change the objects in the room, like changing the sizes, texture, and echo intensity. They concluded that the acoustic perception of bats depend on the correlation between the size of an object and the echo that it produces. That means that a large object must produce a strong echo at par with its size, and a similar concept applies to small objects.
According to Dr. Sasha Danilovich, the study lead author, presenting the bats with objects having an incoherent echo could mislead them and create misconceptions, which makes them repeatedly fly into a wall despite detecting it with their sonar system.
"The experiment gives us a peek into how the world is perceived by these creatures, whose senses are so unique and different from ours," Dr. Danilovich said.
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