By Paul Rodgers
Most creatures that use sound do so for communication, to find a mate, warn off rivals or warn of predators. Bats, and a few other creatures, such as cetaceans, use it differently. Their calls are designed to locate obstacles, prey and each other in space. Or so scientists thought.
Bats can, it turns out, distinguish between calls made by members of their own species and others, even those that are closely related and inhabit similar ecological niches, according to research by scientists at the Max Planck Institute for Ornithology (previously part of the Kaiser Wilhelm Society, which was renamed in honour of the quantum physicist after the Second World War).
Bats living in similar environments tend to use similar echolocation calls to orient themselves and search for food. But in a paper in this month’s American Naturalist, Maike Schuchmann and Bjorn Siemers at the institute’s facility in Seewiesen, Austria, were able to prove that echolocation calls carry more information than assumed.
Horseshoe bat species in Bulgaria were used for the behavioural experiments, in which scientists played the calls of three different species through ultrasonic speakers and analysed the animal’s responses. Both the Bulgarian bat species showed signs of being able to distinguish the calls, although the effect was clearer with calls that were in a clearly separate frequency band from their own.
Siemers reasoned that it would be advantageous for bats to get out of the way of competitively superior species in hunting grounds. And if the other species roosted in similar roosting requirements, identifying them could help the bats find new shelters. The institute’s scientists hope to do follow-up experiments to see whether either of these hypotheses explains the new-found ability.
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