By Matthew Esser
Geographic Range
The range of brown mouse lemurs (Microcebus rufus) includes areas of northern and eastern Madagascar in areas of tropical rainforests and deciduous forests. Brown mouse lemurs can be found in the many protected areas of Madagascar including: Montagne d’ Ambre National Park, Ranomafana National Park, Marojeiy Nature Reserve, and Zahamena Nature Reserve (Harcourt and Thornback, 1990). (Harcourt and Thornback, 1990)
Other Geographic Terms:
island endemic 
.
Habitat
Microcebus rufus inhabits primary and secondary forested habitats, including forest fringes of the coastal rainforests and secondary bamboo forests (Macdonald, 1984). (Macdonald, 1984)
These animals are found in the following types of habitat:
tropical ; terrestrial .
Terrestrial Biomes:
forest ; rainforest .
Physical Description
(1.37 to 3.45 oz; avg. 1.76 oz)
(4.92 in)
Brown mouse lemurs are reddish brown to pale brown dorsally, and white to cream on the underside. The pelage is soft. Between the eyes and down the nose, there is a white or cream colored stripe. The cheeks are brownish-red. The ears are medium sized and membranous with well-developed facial and carpal vibrissae (Macdonald, 1984; Rowe, 1996).
Head and body length is 12.5 cm. Tail length is 11.5 cm. These animals weigh around 50 g, although weights are higher in February and March (Mittermeier et al., 1994). (Macdonald, 1984; Mittermeier, 1994; Rowe, 1996)
Some key physical features:
endothermic ; bilateral symmetry .
Reproduction
Breeding in captivity can take place twice per year.
Breeding occurs during September and October, births occur in November and December.
This species has a ritualistic courtship before breeding which consists of the males using soft squeak calls and tail-lashing to get the female to copulate. Females alert males to their sexual receptivity through frequent ano-genital rubbing and mouth wiping. Females use threat calls to signal to the males that mating is complete (Perret, 1992).
Male territories overlap with those of several females. Dominant males may mate with several females, making a loose sort of harem. (Perret, 1992)
Mating systems:
polygynous .
Brown mouse lemurs mate between September and October. Females experience an estrous cycle lasting an average of twenty days. The gestation period is approximately 60 days. Young are generally born in November and December, with 1 to 3 offspring per litter. Weaning occurs around 2 months of age, so females may produce 2 litters per year in captivity. Sexual maturity is reached after one year of age.
Developing offspring begin to play with their mother, chasing her and jumping on her hands and feet. This may function to help them develop their locomotion skills.
During the months of winter following their birth, the males of the species leave the areas which they were born (Nowak, 1999). (Nowak, 1999)
Key reproductive features:
iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous .
In the three weeks following birth the offspring remain confined to the nest. The mother exhibits extreme commitment to new infants, leaving the nest only to defecate, urinate, feed, or drink. The offspring are dependent for about 2 months, and then they are weaned and able to survive on their own. Weaning begins at the end of February when food is readily available.
Parental investment:
altricial ; pre-fertilization (provisioning, protecting: female); pre-hatching/birth (provisioning: female, protecting: female); pre-weaning/fledging (provisioning: female, protecting: female).
Lifespan/Longevity
[External Source: Max Planck Institute for Demographic Research]
Lifespan in brown mouse lemurs is 6 to 8 years in the wild, but when they are in captivity they can reach 10 to 15 years with an average of 12 years in males (Nowak, 1999). (Nowak, 1999)
Behavior
Brown mouse lemurs are strictly nocturnal. They sleep in tree holes during the day or they make nests in large groups consisting of females and their dependent offspring. From the months of May through September, torpor is exhibited by this species. During this period they can experience a loss of 5 to 35 g in body weight with a reduction in tail circumference from 4 to 12 mm. The tail loses its circumference because it is a major fat reservoir for these animals and during torpor they deplete these reserves. Females usually remain in torpor longer than males (Glaston, 1979).
Brown mouse lemurs also have an extended harem system and exhibit limited polygyny. Male territories are about 200 meters in diameter and will overlap at least two female territories. The home ranges of females are slightly smaller than those of the males. Subdominant males may be found on the periphery of the dominant male territories (Glaston, 1979). (Glaston, 1979)
Communication and Perception
As in all primates, these lemurs are likely to use a variety of modes of communication. Scent marking is important in advertising estrus, as are the visual signals of touching the genitals and wiping the mouth. Tactile communication is important during mating, as are vocalizations, which let the male know when the female is done. (Nowak, 1999)
Food Habits
Brown mouse lemurs are primarily frugivorous, although they also consume insects, young leaves, flowers, gum, and possibly nectar and pollen. Diet varies seasonally with an increase in fruit consumption during the months of December to March. The largest portion of the diet is made up of the fruits produced by plants in the mistletoe genus Bakerella. This genus of plants is foraged upon because of its high fiber and fat content, and is important to build up fat reserves before lemurs enter the season in which they experience torpor.
These animals also consume large insects. They have been found to eat scarab beetles which are 4.5 x 2.5 cm. They also appear to be attracted to flowering trees both for the nectar and for the pollinating insects (Atsalis, 1998). (Atsalis, 1998)
Primary Diet:
omnivore .
Animal Foods:
insects.
Plant Foods:
leaves; fruit; nectar; pollen; flowers; sap or other plant fluids.
Predation
- fossae (Cryptoprocta ferox)
- ringtailed mongooses (Galidia elegans)
- owls (Strigiformes)
- Madagascar harrier hawks (Polyboroides radiatus)
Brown mouse lemurs are preyed upon by raptors, small mammalian predators, humans, domestic dogs, and cats (Goodman et al. 1993). (Goodman, 1993)
Ecosystem Roles
Brown mouse lemurs are likely to be important in dispersing seeds of the fruits they consume. To the extent that they serve as prey for other animals, they may impact predator populations.
Key ways these animals impact their ecosystem:
disperses seeds.
Economic Importance for Humans: Negative
There are adverse effects of brown mouse lemurs on humans.
Economic Importance for Humans: Positive
Brown mouse lemurs, along with other components of the unique, native Malagasy fauna, contribute to ecotourism in Madagascar.
Ways that people benefit from these animals:
ecotourism .
Conservation Status
IUCN Red List: [link]:
Lower Risk - Least Concern.
US Federal List: [link]:
No special status.
CITES: [link]:
Appendix I.
Because of the rate of deforestation on Madagascar, all mouse lemur species are considered at risk by CITES. However, brown mouse lemurs are one of the few native Malagasy primates that are still relatively common throughout their range.
For More Information
Find Microcebus rufus information at
Contributors
Matthew Esser (author), University of Wisconsin-Stevens Point.
Chris Yahnke (editor), University of Wisconsin Stevens Point.
Nancy Shefferly (editor), Animal Diversity Web Staff.
