Small bats squeak at higher pitch to focus better, study reports

November 21st, 2012 in Biology / Plants & Animals
Fruit bats hang from a tree in Gayndah, South Eastern Queensland in 2011. Small bats have to emit higher-pitched squeaks than their bigger cousins for their sonar navigation systems to work equally well, scientists said Wednesday.


Fruit bats hang from a tree in Gayndah, South Eastern Queensland in 2011. Small bats have to emit higher-pitched squeaks than their bigger cousins for their sonar navigation systems to work equally well, scientists said Wednesday.

Small bats have to emit higher-pitched squeaks than their bigger cousins for their sonar navigation systems to work equally well, scientists said Wednesday.

Bats use sonar signals to navigate in dark spaces, known as , but scientists have been at a loss to explain why the smaller species' pitch was higher than considered necessary to locate their prey.

In measuring the signals emitted by six distinct , a team from the University of Southern Denmark found the answer: the size of the creatures' mouths.

Because of their relatively smaller "emitters" or mouths, smaller bats must emit their squeaks at sufficiently to produce focused, highly-directional sound beams, explained a statement on the report published in Nature.

If they were to squeak at the same pitch as their bigger cousins with bigger mouths, the winged mammals' signals would travel a shorter distance and be scattered, said the study.

"Thus all bats adapted their calls to achieve similar acoustic fields of view," the authors wrote.

More information: DOI: 10.1038/nature11664

(c) 2012 AFP

"Small bats squeak at higher pitch to focus better, study reports." November 21st, 2012. http://phys.org/news/2012-11-small-higher-pitch-focus.html