Aye ayes possess a unique combination of highly derived morphological features.

The incisors (front teeth) have been reduced to a single pair that grows continuously, as in rodents.

These teeth are used to gnaw into hard-shelled fruit such as coconuts and to tear bark off trees.  

Aye ayes have a specialised thin, flexible middle finger that is used during foraging tasks that require high mobility and precision.

Like most lemurs, ayes ayes have retained a reflective layer of tissue in the eye - the tapetum lucidum - that improves vision in low-light conditions and causes eye-shine.

Ayes ayes have long, coarse hair, large ears and a bushy tail that is longer than their body.

They are the largest nocturnal primate with both males and females weighing approximately 2.6 kilograms.