Habitat/Conservation
The east and west coasts of Madagascar provide very two different forest habitats for four similar subspecies of dwarf and mouse lemurs. Cheirogaleus medius (the fat-tailed dwarf lemur) and Microcebus murinus (the gray mouse lemur) occupy the west, while Microcebus rufus (brown mouse lemur) and Cheirogaleus major (greater dwarf lemur) live in the east. These subspecies' smallness, nocturnality and ability to live in secondary forests have protected both dwarf and mouse lemurs from threats of extinction. However, as with all lemurs of Madagascar, habitat destruction and hunting increasingly threaten their survival.
In the eastern rainforest of Madagascar, conditions do not fluctuate as much as in the west, so eastern lemurs display less of a need for seasonal torpor. Eastern dwarf lemurs have a shorter period of dormancy than their western cousins: For example, Microcebus rufus, with a body mass ten times smaller than Cheirogaleus major, feeds on fruits and insects through the winter, and doesn’t go into torpor at all.
Mouse and dwarf lemurs breed well in captivity, but since populations are not endangered in the wild, captive population numbers are low and steadily shrinking.