At one time in the fairly recent past, the genus Microcebus was thought to contain just two species with non overlapping ranges: the gray mouse lemur (M.murinus) found in the drier regions of the north, west and south and the rufous or brown mouse lemur (M.rufus) of the humid rainforest regions of the east. However, the world of primatology was rocked in 2000 with the announcement that no less than three new species of mouse lemurs had been discovered by an international team of primatologists working in the endangered forests of western Madagascar! Additional research has brought the total number of mouse lemur species to eighteen. Needless to say, in this day and age it is extremely rare that any new species of primate is discovered, and this new diversity of mouse lemur species is remarkable! Like the fat-tailed dwarf lemur, the gray mouse lemur usually undergoes a season of torpor during Madagascar’s dry season (April/May to September/October). At this time, female mouse lemurs become totally inactive and may remain dormant within their tree holes for several months (up to 176days). This conserves energy and reduces the threat of predation during the time of year when resources are scare. During this time, however, males might be much more active than females, perhaps establishing hierarchies for the upcoming breeding season. Prior to the dry season both sexes store large reserves of fat in their hind legs and tail (up to 35% of body weight) which helps get the animals through the period of resource scarcity.
Adult Size : 1 ½ – 3 ounces
Social life : Solitary forager, strictly nocturnal, sleeps in groups
Habitat : western dry deciduous forest
Diet : insects (mostly beetles), fruit, flowers and leaves
Lifespan : 10 – 15 years in captivity
Sexual maturity : 1 year in captivity
Mating : Extremely seasonal, Gestation: 59 – 62 days Number of young: usually twins, one pair per year
DLC Naming theme : Various herbs and birds (Wintergreen, Sandalwood, Buckthorn, etc.)
Malagasy names : Tsidy, Koitsiky, Titilivaha, Vakiandri, Pondiky
In Madagascar, grey mouse lemurs are sometimes sighted in gardens and roadside brush.
Until recently, grey mouse lemurs were thought to be the smallest living primate. This was disproven when the pygmy mouse lemur (Microcebus myoxinus), thought to be extinct, was re-discovered.
The grey mouse lemur is one of the most widespread, abundant, and adaptable lemur species.
Some gray mouse lemurs actually have a reddish pelage color!
The gray mouse lemur is a solitary forager.
It feeds primarily on insects (mostly beetles), fruit, flowers and leaves.
In the wild, mating occurs in mid-September, and infants are born 59 – 62 days later in November. The infants, usually twins, are born in a leaf nest or tree hole, and are carried in their mother’s mouth if moving them becomes necessary. Infants are independent at two months.
Grey mouse lemurs are nocturnal, solitary foragers who congregate at daytime sleeping sites. Females and dependent offspring will sleep in groups of up to 15. Home ranges of females are grouped into core areas and one male’s home range can overlap those of several females. Females are considered to be dominant over males, giving them preferential access to food and the choice of with whom to mate. (Female dominance in primates is unique to prosimians.)
Habitat & Conservation Concerns
Grey mouse lemurs are found throughout the dry deciduous forests from Majunga in the northwest to Tulear in the southwest. A disjunct population has also been identified in the southeast near Fort Dauphin.
The gray mouse lemur is one of the most widespread, abundant and adaptable lemur species. It is also among the least threatened. It is able to survive in slightly altered habitats and is therefore less threatened by occasional logging than most lemur species. It is also found in all of the protected areas within its range. Some of the newly described mouse lemur species have a much smaller distribution and are endangered due to habitat loss (i.e. the golden-brown mouse lemur, Microcebus ravelobensis and the Sambirano mouse lemur, M. sambiranensis.
The Duke Lemur Center houses North America’s only breeding colony of grey mouse lemurs with a total of 48 individuals, 24 males and 24 females. New research shows that mouse lemurs can develop symptoms of neurological disorders similar to Alzheimer’s disease and dementia. Past research on such diseases has been conducted on lab rats and mice, but mouse lemurs- being more similar to humans genetically- show more promise for breakthroughs in neurological aging research. All of the aging research conducted at DLC adheres to our strict no-harm, noninvasive policy. In addition, mouse lemur breeding at DLC follows Species Survival Plan guidelines for preserving genetic diversity.