This paper provides descriptive and quantitative information on the development of a young aye-aye in captivity during its first 10 months of life. The mother’s behaviour was observed to provide an adult standard against which to evaluate the young male’s development. Early development of the young aye-aye (including early vocalizations, locomotion and manipulation, acquisition of independence from the mother, threat/ defence and alarm) is described in qualitative terms. Quantitative data on a number of other behaviours were collected using focal-animal sampling. Overall, this study indicated that the young aye-aye is relatively poorly developed during the 2-month nest phase but shows rapid development in comparison to other primates once it has left the n