Cognitive capacities of captive gray mouse lemurs as evidenced by object manipulation

Abstract

Observations using infrared photography have shown that captive Microcebus murinus are capable of manipulating various objects when appropriately motivated. I tested the capacity of ten adult males to reach a learning criterion to obtain a mealworm placed in a box that opened several ways, followed by a series of related but more complex tasks. Despite individual differences, the animals managed to solve all problems more and more rapidly; in particular, those requiring successive, simultaneous manipulations or changes of behavioral strategy. Additional tests indicated that learning could be achieved in very young subjects (4.5 months) and was retained long term (one year). In addition, video recordings demonstrate that learning criteria can be acquired progressively (notably by social imitation) or spontaneously (resulting from an "insight"). The facility with which mouse lemurs learn object manipulation indicates sophisticated cognitive abilities which probably contributed to their evolutionary success in Madagascar.