Key: Step 3. small to medium sized

2a. Length of the head and the body from 10 to 25 cm. The tail is two-thirds of the length of the body. Nocturnal animals sleeping during the day in tree holes or in nests.

Step 4. small sized

2b. Length of the head and the body from 25 to 35 cm. The tail is half of the length of the body. Strictly nocturnal and moving about in jumps with the body in a vertical position, except for Hapalemur.

Step 16. medium sized