Have you ever seen a group of bats and wondered how they fly without ever colliding into one another or trees? Most navigate via echolocation; that is, they emit high-pitched sounds (which we cannot hear) that reflect off of surrounding objects and return to them. The bat brain decodes the returning sounds to give the bat a precise idea of the location and size of the object. But many biologists have thought that “clutter” must be a problem. Scientists have thought that with so much going on around them, with so many other bats flying nearby, and with so many other objects in the landscape, bats would not be able to see the forest for the trees, so to speak.
However, Dr. Brock Fenton from the University of Western Ontario, who spoke at UTM last week, doesn’t think there is a problem-he thinks that bats can cope with clutter quite well. He likens this phenomenon to looking for a particular item in a very cluttered store.
A person may walk into a store and be overwhelmed by the sheer volume of items. However, if one is looking for something specific, like a bracelet, the brain will focus automatically on the rack of jewellery while ignoring all other stimuli. Similarly, Dr. Fenton believes that bats have perceptual systems that allow them to simply focus in on reflected sounds from their prey and ignore the other reflected noise surrounding it.
He also believes that bats change the sounds they emit depending on the situation. Bats will shift to a higher or lower sound when they find themselves flying near another bat that is emitting at a similar frequency, in order to avoid jamming. Comparing bat echolocation to highway driving, Dr. Fenton believes that when navigating in a large group, bats ignore nearly all input and focus entirely on “watching the taillights of the bat in front of them.”
It is even thought that bats have social calls, andoccur for a much longer duration, which communicate to their neighbours such information as their position and destination, and locations of food.
