Microcebus murinus (Miller 1777) is the extant gray mouse lemur an omnivore found only in Madagascar. Traditionally this is the largest species of the smallest primate genus, but in the LRT this is the basal taxon in the lineage of bats. Relatives include Hapalodecte, Ptilocercus and Onychonycteris. The eyes are large, typical of nocturnal mammals. This nocturnal arboreal tree shrew forages alone, but sleeps in groups, sharing tree holes during the day.

Microcebus is mostly insectivorous. They occasionally eat small reptiles such as chameleons and tree frogs. They also feed on plants, leaves, fruits and flowers. It lives in dense tropical forests.

Twin babies are typical. Labor takes about 45 to 60 minutes and the infants begin to suckle after about 12 minutes. The infants weigh from 5.5-7g and are carried in the mother's mouth.Offspring can reproduce after one year and a lifespan of ten years.

Since it lives in Madagascar along with all the lemurs, its genes, affected by endemic viruses, align with lemurs.