If it seems too good to be true, the old cliché goes, it probably is. And it doesn’t get much gooder than the bizarre hand of the aye-aye, a specialized lemur that uses a hyper-elongated middle finger to tap along hollow tree branches, listens for grubs within, gnaws a hole in the wood, and reaches that middle finger inside to fish out the food. It would seem, then, that the aye-aye (so named because of its cries) wanders the forests of Madagascar giving the world the highly elongated finger.
But now, a discovery that really ruins that gag: While exploring the anatomy of the aye-aye’s forearm and hand, a group of researchers discovered the critter has tiny pseudothumbs that likely help it grip branches. Technically speaking, then, the aye-aye has six digits on each hand, so it has no middle finger. Thus in one discovery, the aye-aye grows more remarkable yet less joke-worthy.
Found only on Madagascar, the aye-aye’s got the tail of a squirrel, the ears of a bat, and a perpetual look like it just realized it left the oven on. Surely its most bizarre adaptation, though, is that exceptional finger. Ambling along dead branches, it rapidly taps the wood, cocking its giant ears to pinpoint insect larvae squirming within. Target acquired, it tears at the wood with rodent-like teeth that are both continually growing, like a beaver’s, and so strong that in captivity aye-ayes have been known to chew through cinder blocks. Once it has torn open a hole, the hunter reaches in with that long, thin finger, which actually swivels in a ball-and-socket joint, like a human’s shoulder. At the end of the finger is a hooked nail that snags the grub and drags it out.