What is an aye-aye?

Aye-aye captain, less than cute furry creatures full steam ahead. The well adapted aye-aye is the only primate to use echolocation to find its prey.


Lemurs exist only on the island of Madagascar. Most of these primates are furry, cuddly-looking creatures, except one: the aye-aye.

The aye-aye possesses rodent-like teeth that never stop growing, piercing eyes that allow it to forage at night and a middle finger so long and bony that it almost looks like a spider’s leg. Incredibly, the aye-aye has woodpeckers to thank for this latter adaptation.

Woodpeckers never made it to Madagascar, which meant the aye-aye could fill the niche for eating wood-boring grubs. The animal taps its elongated middle finger against tree stumps to locate grubs, listening for the tell-tale echoes of hollow areas, which indicate the presence of food. This hunting technique makes the aye-aye the only known primate to echolocate its prey: hence its extraordinarily sensitive, bat-like ears.

The aye-aye is to lemurs what Stephen King’s Pennywise is to clowns, at least according to local Malagasy legend. One belief is that this creature creeps into the houses of villagers at night and uses its elongated finger to slit the throats of sleeping children. The truth – if you’re a grub – is just as grisly.

Read more:

Subscribe to BBC Science Focus Magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun facts.