Bats use leaves as “mirrors” to understand the presence of resting insects

Bats have a particular localization system that involves sight and hearing to understand, even in darkness, the position of obstacles and even prey, and this is a well-known thing. However, a new study, published in Current Biology, shows how sensitive these animals are through their echolocation system.

Capturing insects and intercepting them in the dark is an impossible task for many, but not for bats. The experiments that the scientists of the Smithsonian Tropical Research Institute (STRI) have conducted, in fact, show that bats are able to trace even acoustically camouflaged prey, that is to say silent prey on the leaves.

Bats are able to hunt these insects thanks to a sort of sixth sense: they flood the surrounding area with sound waves and then use the return echoes to navigate through the environments. However, they also do this with regard to objects of limited extension such as the leaves: the latter reflect the signals and if the latter is a little weaker because there is an insect resting on the bats they can recognize the difference. And this also in a tropical forest, in the thick foliage that characterizes this environment.

Scientists have discovered that if the sound bouncing off the leaves comes from oblique angles greater than 30 degrees, the leaves themselves can behave like “mirrors” like a lake reflects the surrounding forest at dusk at dawn. This means, according to the researchers, that the same angle of approach makes the insect at rest detectable. Therefore the same researchers have deduced that the bats tend to approach the insects that rest on the leaves through angles comprised between 42 and 78 degrees, considered optimal angles to discern the same presence of the insect on the leaf.