Book 33, Question 117
Why does the aye-aye tap on trees?
The aye-aye is a lemur from Madagascar with big ears and a very long, thin middle finger.
It taps on tree branches with that finger and listens for hollow spots with its big ears. When it finds one, it gnaws a hole and uses the finger like a hook to pull out insect grubs. It is a night-time hunter with a built-in tapping tool.