A nocturnal lemur of Madagascan forests. Its long thin middle finger helps it locate insects inside wood.
It has large ears and long fingers, with a middle finger thinner than the others. Dark fur covers the body and the tail is bushy.
The aye-aye has a small “pseudothumb” at its wrist. In a study published online in 2019, researchers examined six adults and one immature individual and found this digit in all seven. This was the first pseudothumb reported in a primate. It combines an enlarged wrist bone and cartilage, has attachments from three muscles, and bears its own palm pad and fingerprint pattern.
Its muscles may allow it to move outward, inward, and oppose the other digits. Since the long middle finger is specialized for tapping and extracting larvae, the authors propose the pseudothumb may assist with gripping.
IUCN Red List of Threatened Species · Endangered (EN) · Global
Habitat loss and hunting are threats. In some areas aye-ayes are killed as crop pests or because they are considered bad omens.
The 2020 IUCN global assessment lists the aye-aye as Endangered (EN). It was assessed on 7 May 2018 and records a decreasing population trend. The assessment suspects a decline of at least 50% over 36 years, driven primarily by continuing loss in habitat area and quality and unsustainable hunting.