Bats are famous for their sonar-based navigation. They use their extremely sensitive hearing for orientation, emitting ultrasound noises and receiving an image of their surroundings based on the echo. Seba's short-tailed bat (Carollia perspicillata), for example, finds the fruits that are its preferred food using this echolocation system. At the same time, bats also use their voices in a somewhat deeper frequency range to communicate with other members of their species. Seba's short-tailed bats employ a vocal range for this purpose that is otherwise only found among songbirds and humans. Like humans, they produce sound through the larynx.
Together with his team, neuroscientist Julio C. Hechavarria from the Institute for Cell Biology and Neuroscience at Goethe University investigated brain activity preceding vocalisation in Seba's short-tailed bats. The scientists were able to identify a group of nerve cells that create a circuitry from the frontal lobe to the corpus striatum in the interior of the brain. When this neural circuit fires off rhythmic signals, the bat emits a vocalisation about half a second later. The type of rhythm seemed to determine whether the bats were about to utter echolocation or communication vocalisations.
