Reaction to new objects and spatial changes in young and aged grey mouse lemurs (Microcebus murinus)

The exploratory behaviour of young and grey mouse lemurs (Microcebus murinu s) in an experimental enclosure containing various objects was recorded. A new object was added for each test session and could displace an object tha t had previously been introduced to a new position. For young grey mouse le murs, there was an obvious preference for new objects and for displaced fam iliar objects. This indicates that they are able, like other primates, to " map out" and memorize their environment. For the aged grey mouse lemurs, pr eference for the new objects was very slight. No reaction to changes in the location of familiar objects was noted. Age-related deficits in memory, in particular spatial memory, could account for this lack of response to chan ges in the environment.