We do it just the same as the fruit bats do!
12th February, 2018: New research from the
University of Washington and published as open-access paper in PLoS Biology,
reports that the Egyptian fruit bat is using similar techniques for navigation
as used in modern-day military and civil surveillance. The same technique could
give new directions for development of navigation system for driverless cars
Wu-Jung Lee, a researcher at the UW’s Applied Physics Laboratory, and the lead author of the paper says: “This bat species is actually very special -- it may be using a similar technique that engineers have perfected for sensing remotely.”
As different from bats, which emit high-pitched squeals, the fruit bat simply clicks its tongue and produces signals. In this, they are more like dolphins. Further, fruit bats can also see quite well in bright environments and they switch between the sensory and audible modes of navigation depending on the brightness and darkness of the environments.
Further, Egyptian fruit bats are able to send clicks in different directions without moving their head or mouth. This enable them to perform echo-based location more effectively and they navigate excellently well in all circumstances.
Lee found that the fruit bats simultaneously emit different frequencies of sound waves, which sends different frequencies of sound in different directions. It is found that the elongated shape of the bat’s mouth creates varying distances between the sound source and the gaps between its teeth. This creates positive or negative interference between sound waves of different frequencies. In this way the fruit bats can emit different wavelengths of sound in different directions as done by modern frequency-scanning sonar.
“This may be a way to produce a very cheap sensor that has this kind of sensing capability,” opines the author.