The aye aye is the only surviving member of the family Daubentoniidae - 1 of 5 families of lemuriform primates that are found only on the island of Madagascar.
Early naturalists found the aye aye difficult to place taxonomically due to its bewildering combination of morphological characteristics, and it was variously classified as a squirrel, rodent or primate.
A detailed anatomical investigation by Richard Owen secured their status as primates - he later became the first Director of the Natural History Museum.
Subfossils of a giant form of extinct aye aye, Daubentonia robusta, are found at sites in the south and southwest of Madagascar.
The extinct species weighed 2 to 5 times as much as the living aye aye and may have been driven to extinction as a result of human actions.