The aye-aye's tap hunting

Madagascar is home to the nocturnal aye-aye, a primate with an unusually long, slender middle finger. It taps on wood and listens to the reverberations to locate cavities containing larvae; it then gnaws into the wood with its incisors and extracts prey with the finger. This is called percussive foraging or tap-scanning and resembles a woodpecker’s search, but it is not true echolocation: the aye-aye does not emit its own sonar calls, instead listening to sounds produced by tapping the substrate.