Dwarf Lemurs and Mouse Lemurs: Cheirogaleidae
DWARF LEMURS AND MOUSE LEMURS: CheirogaleidaeRED MOUSE LEMUR (Microcebus rufus): SPECIES ACCOUNT
Dwarf lemurs and mouse lemurs are the smallest lemurs. The pygmy mouse lemur weighs just one ounce (30 grams). The largest of these lemurs is the fork-crowned lemur, weighing 16.5 ounces (460 grams), or about a pound. The head and body length of dwarf and mouse lemurs ranges from 4.9 to 10.8 inches (12.5 to 27.4 centimeters), depending on species. Tail length is about as long as total body length.
Dwarf and mouse lemurs have large ears and large, mirror-like eyes set close together. They have excellent night vision. Depending on where they live, these lemurs may have grayish hair or reddish brown hair. Their underbody hair is much lighter, sometimes whitish or yellowish brown. Body hair is soft, thick, and woolly.
Dwarf and mouse lemurs live in Madagascar, an island off the southeast coast of Africa.
Dwarf and mouse lemurs live in a variety of forested habitats, including evergreen rainforest, deciduous forest where trees lose their leaves each year, and semiarid forest, which doesn't get rain part of the year. Mouse lemurs are also found in patches of scrub vegetation where there are small bushes, and in people's gardens in settled areas.
Dwarf and mouse lemurs usually eat fruit and insects, but some species prefer other foods too. Coquerel's mouse lemur licks the sweet body liquids that are the waste matter produced by some planthopper insects. Fork-crowned lemurs primarily feed on plant gums, or sticky plant liquids. Many of the dwarf and mouse lemurs slow down in the dry season when plants and insects are not as readily available. They survive on stored body fat in their tail until the plentiful rainy season starts, when they become active again.
BEHAVIOR AND REPRODUCTION
Dwarf and mouse lemurs are nocturnal, or active at night. They search for food by themselves, usually in the smaller branches of trees and shrubs.
Dwarf and mouse lemurs are quite social. They have group nests, which they share during the day. The nests can be within tree hollows or tree branches. Five of the little fat-tailed dwarf lemurs may share a tree hole. Mouse lemur nests may have two to nine residents. These nests may have female dwellers, with the males nesting alone or in pairs, or both male and female dwellers. Dwarf lemurs have male-only or female-only nests. Communication is with scent and a variety of calls. Calls include those for keeping contact, mating, alarm, and distress.
Mouse and dwarf lemurs usually travel along branches on all four legs, leaping at times. They can use their tail for balance. Some species can take long leaps from one branch to another. A gray mouse lemur may also move on the ground with froglike hops. Each species, or type, of dwarf or mouse lemur marks its trail with scent while traveling. These markings, deposited by scent or smell glands, or from urine, give information about the traveler's age, sex, and whether it is ready for mating.
Female mouse lemurs are all ready to mate at one time. Male mouse lemurs can defend only one female at a time. So it's very difficult to keep a group of females all to themselves for mating. Rather than do a lot of fighting, dominant males have a way to put other males out of action. The urine of stronger male mouse lemurs contains chemicals producing a smell that makes weaker males sterile, or unable to reproduce. In addition, these weaker males can't even make the special trills, or calls, used to attract females for mating.
After mating, mouse and dwarf lemur females have a two- to three-month pregnancy, depending on species. They may have one to three infants each birth. Births usually take place during the rainy season, when food is plentiful. The smaller mouse lemur infants weigh about 0.175 ounces (5 grams) each. The larger Coquerel's mouse lemur infants can have a birth weight of 0.42 ounces (12 grams) each. Mouse and dwarf lemur infants are raised in a nest made of twigs and leaves.
DWARF AND MOUSE LEMURS AND PEOPLE
Dwarf and mouse lemurs are not often hunted for food because of their small size.
Dwarf, red, and gray mouse lemurs are still fairly common. However, they and other small lemur species are at risk due to destruction of their forest habitats, or dwelling places, by human logging, farming, and cattle and goat grazing. It is estimated that only 10 percent of Madagascar's forests remain. The World Conservation Union (IUCN) lists three species as Endangered, facing a very high risk of extinction; one as Vulnerable, facing a high risk of extinction; and one as Near Threatened, not currently threatened, but could become so.
Physical characteristics: The red mouse lemur, also called the russet mouse lemur and the brown mouse lemur, is reddish brown on its back and light gray or whitish underneath. It has a whitish stripe between its large round eyes. Its moveable ears are rounded, thin, and hairless. Red mouse lemurs are among the smallest primates. An adult is 5 inches long (12.5 centimeters) with a 5.6-inch tail (14 centimeters). A full-grown red mouse lemur weighs 1.5 ounces (43 grams). Females are about the same size as males.
Geographic range: Red mouse lemurs are found in eastern Madagascar.
Habitat: Red mouse lemurs live in coastal rainforests.
Diet: The red mouse lemur eats a lot of fruit, preferring fruit from plants in the mistletoe family. It also eats insects, spiders, flowers, and gum, or plant juices, and occasionally small frogs and lizards. These lemurs have been seen eating millipedes and scarab beetles as big as they are.
Behavior and reproduction: The red mouse lemur lives in trees and travels through all forests heights. It makes round, leafy nests in hollow trees or among branches. It sleeps during the day, and is nocturnal, active and feeding at night. Each red mouse lemur searches for food by itself. From July to September, fat is stored in its tail. A tail with stored fat may increase this mouse lemur's weight by 1.6 to 2.6 ounces (50 to 80 grams). Then, during the harsh dry season, June to September, it slows down considerably for short periods, becoming almost motionless, utilizing its stored fat as food.
From two to nine male and female red mouse lemurs usually share a sleeping nest. Males may also nest by themselves or in pairs. Home ranges vary with food availability. Males usually have a larger home range than females.
The red mouse lemur has several ways of moving. It runs along branches on all four limbs, like a squirrel. It also may leap as far as 9.8 feet (3 meters) from one tree branch to another, landing on all four limbs. Its long tail helps with balance.
The mating season of the red mouse lemur is from September to October. The female is pregnant about two months, and gives birth to one to three infants. A newborn weighs about 0.18 ounces (5 grams). The infants stay in their nest for three weeks, with the mother leaving only briefly to seek food and water. Weaning, or taking the young off breastmilk, occurs in February when there is the greatest amount of food available.
Red mouse lemurs and people: These lemurs are not considered important by local people.
Conservation status: The red mouse lemur is common in some areas, but could become threatened due to losing habitat through logging and grazing by cattle and goats. ∎
FOR MORE INFORMATION
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Kavanagh, Michael. A Complete Guide to Monkeys, Apes and other Primates. New York: The Viking Press, 1983.
Lasky, Kathryn. Shadows in the Dawn: The Lemurs of Madagascar. New York: Gulliver Books, 1998.
Powzyk, Joyce A. In Search of Lemurs. Washington, D.C.: National Geographic, 1998.
Sleeper, Barbara. Primates. San Francisco: Chronicle Books, 1997.
Banks, Joan. "Living on the Edge: On the Verge of Extinction, Do Lemurs Have a Fighting Chance?" National Geographic World (Jan–Feb 2002): 12–17.
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Mitchell, Meghan. "Securing Madagascar's Rare Wildlife." Science News (November 1, 1997): 287.
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"Cheirogaleidae: Dwarf Lemurs, Mouse Lemurs." Animal Diversity Web. http://www.Primates.com/primate/cheirogaleidae.html (accessed on July 5, 2004).
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