Dwarf lemurs and mouse lemurs

(Cheirogaleidae)

Class Mammalia

Order Primates

Suborder Prosimii

Family Cheirogaleidae

Thumbnail description
Dwarf and mouse lemurs are the smallest of the Madagascar lemurs, with colors ranging from gray to dark brown dorsally and cream to yellowish brown ventrally; some have conspicuous facial markings (e.g., dark rings around the eyes; pale nose stripe)

Size
Head and body length, 5–11 in (12–27 cm); weight 1–16.5 oz (30–460 g)

Number of genera, species
5 genera, 17 species

Habitat
Members of this family are found throughout Madagascar in all forest types; all species are nocturnal and essentially arboreal

Conservation status
Endangered: 3 species; Vulnerable: 1 species; Lower Risk/Near Threatened: 1 species

Distribution
Restricted to forested regions of Madagascar

Evolution and systematics

There is no fossil record in Madagascar for any lemurs, although mouse lemur skulls have been reported among subfossils from sites just a few thousand years old. An Eocene primate from Pakistan, Bugtilemur, shows some similarities to modern dwarf lemurs (Cheirogaleus) in molar tooth morphology and was therefore allocated to the family Cheirogaleidae by its discoverers.

Chromosomal and molecular evidence overwhelmingly indicates that lemurs are a monophyletic group (i.e., all derived from a specific common ancestor), thus resolving a conflict in interpretation of morphological characters. At one time, numerous authors suggested that the dwarf and mouse lemurs (Cheirogaleidae) are closer to the loris group (Lorisiformes) than to other lemurs, but this has now been effectively discounted. Within the adaptive radiation of the Madagascar lemurs, it is equally clear that dwarf and mouse lemurs belong to a monophyletic subgroup, derived from a later common ancestor retaining many primitive features from the earliest lemurs. While chromosomal and molecular evidence indicates that the aye-aye (Daubentonia) branched away first during diversification of the lemurs, relationships between the remaining four families (Cheirogaleidae, Lemuridae, Lepilemuridae, Indriidae) remain unresolved, probably because they separated from one another relatively quickly.

Physical characteristics

These are the smallest lemurs, ranging in size from 1 oz (30 g) for the pygmy mouse lemur (Microcebus berthae) to 16.5 oz (460 g) for the fork-crowned lemur (Phaner furcifer). All species are nocturnal, with correspondingly large eyes, and essentially arboreal, with relatively long tails. The tarsal bones in the heel region of the foot are mildly elongated. The fur is dense and woolly in all species. As a general rule, species inhabiting the eastern rainforest tend to be rufous (reddish brown) in dorsal coloration, while those living in the dryer forests in the west are grayer. In all species, the ventral fur is considerably lighter and varies from white through cream to yellowish brown. The external ears (pinnae) are relatively large and, in some species, very conspicuous.

Distribution

Species of the genera Cheirogaleus and Microcebus occur throughout the forested regions of Madagascar, while the hairy-eared mouse lemur (Allocebus), Coquerel's lemur (Mirza), and fork-crowned lemurs (Phaner) have more restricted ranges.

Habitat

All species are essentially arboreal and use nests of some kind. Mouse lemurs (Microcebus and Mirza) construct globular leaf-nests but can also use tree hollows, whereas dwarf lemurs (Cheirogaleus), hairy-eared mouse lemurs, and fork-crowned lemurs typically use tree hollows.

Dwarf and mouse lemurs are found in every kind of forested habitat in Madagascar, including evergreen rainforest in the east, deciduous forest in the northwest and west, and semiarid forest in the southwest and south. Mouse lemurs (Microcebus species) also occur in small patches of scrub vegetation and even in gardens in settled areas.

Behavior

Although they typically forage alone at night, all species in the family Cheirogaleidae live in social networks involving

overlapping ranges, occasional contacts during the night, and nest sharing during the day. However, the degree of tolerance between same-sex adults varies, such that some species (e.g., mouse lemurs) live in dispersed multi-male/multi-female groups, while others (e.g., dwarf lemurs) live in dispersed monogamous groups.

Because all species are typically solitary while foraging, social communication during the night is mainly based on vocalizations and scent marking. Due to their small body sizes,

most vocalizations are relatively high-pitched and the small-contact, alarm, threat, and range defense. According to species, scent marking can involve deposition of urine, feces, or secretions of special skin glands.

All species show some degree of home-range defense between adults of each sex, but only those that are clearly monogamous (Cheirogaleus) or that show a tendency to monogamy (Mirza and Phaner) defend an exclusive territory.

All dwarf and mouse lemurs are exclusively nocturnal. Smaller species show incomplete control of body temperature, which declines during daytime sleep, and varying degrees of torpor, ranging from facultative to obligatory. Fat may be stored in the tail during the rainy season as a reserve for torpor during the dry season.

Feeding ecology and diet

Fruits and insects are the staple diet for most dwarf and mouse lemurs, but each species shows a particular specialty, sometimes involving plant exudates (gums). Whereas dwarf lemurs feed mainly on fruits, mouse lemurs tend to eat a relatively balanced diet of fruits and insects. However, Coquerel's mouse lemur also consumes secretions produced by insects as part of its diet. Gum-feeding occurs to a limited extent in both

Cheirogaleus and Microcebus species, but fork-crowned lemurs are heavily specialized on this food source as the main dietary intake. Some species also feed on nectar from flowers (e.g., Cheirogaleus and Phaner).

Most species tend to concentrate foraging activity for fruits and insects in the fine branches of trees and bushes, but fork-crowned lemurs spend much time on tree trunks searching for gums.

As an adaptation to gum-feeding, fork-crowned lemurs have a particularly well-developed tooth comb in the lower jaw. They also have sharply pointed tips (needle-claws) on the nails of all digits, except the big toe, for clinging to broad trunk surfaces while feeding on gums. The caecum (located at the extreme of the colon) is enlarged in Phaner as an adaptation for digestion of gum assisted by symbiotic bacteria. The presence of needle-claws in the hairy-eared mouse lemur suggests that this species also feeds regularly on gums.

Reproductive biology

In all dwarf and mouse lemurs, females show a clear-cut brief period of estrus. In the smaller species, a membrane seals the vulva most of the time. Estrus is marked by the swelling and opening of the vulva, and in some species a vaginal plug is formed after mating. Males actively pursue estrous females in the trees, and in most or all species the male emits a specific mating call. In species with a multi-male/multi-female social system (e.g., Microcebus species), several males can mate with a female during estrus, and genetic tests have shown that different fathers may sire offspring in the same litter. The gestation period, lasting between two and three months according to species, is relatively short compared to other primates. All species typically rear their offspring in a nest. The smaller dwarf and mouse lemurs have multiple litters commonly containing two to three offspring, whereas the larger species usually have a single offspring. Suckling occurs relatively frequently during the night, so mothers must reduce their activity away from the nest for some weeks after birth. Strictly seasonal breeding is found in all species. Births typically take place during the wet season (October–March).

Conservation status

At one time all lemurs were classified as Endangered and as a result all are included in Appendix I of the CITES legislation. However, some mouse lemurs (e.g., Microcebus murinus, M. rufus) are in fact very widespread in Madagascar, occurring in all kinds of habitats, including domestic gardens. However, two mouse lemur species with very restricted ranges are listed as Endangered (M. berthae and M. ravlobensis). Most dwarf lemurs are also quite widespread, although less common than M. murinus and M. rufus species. Species in the remaining genera (Allocebus, Mirza, and Phaner) all have much more restricted geographical distributions. Allocebus trichotis is listed as Endangered, Mirza coquereli as Vulnerable, and Phaner furcifer as Near Threatened.

Significance to humans

Dwarf and mouse lemurs are all too small to be of much significance to humans. They may occasionally be eaten, but the amount of meat obtained is generally too limited to make targeted hunting worthwhile, with the possible exception of fork-crowned lemurs.

Species accounts

List of Species

Hairy-eared mouse lemur

Allocebus trichotis

subfamily

Cheirogaleinae

taxonomy

Cheirogaleus trichotis (Günther, 1875), Madagarcar, between Tamatave and Morondava.

other common names

French: Allocèbe; German: Büschelohrmaki; Spanish: Lemur orejipeludo.

physical characteristics

Conspicuous tufts of hair on relatively small, rounded ears. Dorsal fur is brownish gray with darker midline stripe down back; ventral fur light gray. Tail hair darkens towards tip. Narrow, dark rings surround eyes. Nails are small with sharp tips on all digits except the big toe. Length 5.6 in (14 cm), tail 6.8 in (17 cm); 3 oz (85 g).

distribution

Northeastern Madadascar, inland from Mananara just south of the Bay of Antongil; near Mananara in the Zahamena Reserve and in the Vohidrazana forest; Allocebus may occur north of Mananara on the Masoala peninsula.

habitat

Canopy of evergreen rainforest.

behavior

Individuals are solitary when active, but nesting groups have been recorded.

feeding ecology and diet

Basic diet of fruit and insects; some gum-feeding.

reproductive biology

Largely unknown. Birth season thought to be January–February.

conservation status

May be locally abundant in small areas, but listed as Endangered.

significance to humans

None known.

Greater dwarf lemur

Cheirogaleus major

subfamily

Cheirogaleinae

taxonomy

Cheirogaleus major É. Geoffroy, 1812, Fort Dauphin, Madagascar.

other common names

French: Grand cheirogale; German: Grosser Katzenmaki.

physical characteristics

Dorsal fur medium brown to deep reddish brown; ventral fur creamy white or yellowish white. Eyes surrounded by dark rings and separated by a pale stripe. Ears medium-sized and naked, but partially hidden by surrounding fur. Length 9.6 in (24 cm), tail 11.2 in (28 cm); 16 oz (438 g) for males, 13 oz (362 g) for females.

distribution

Occurs throughout the eastern rainforest of Madagascar, from the extreme north to the far south.

habitat

Evergreen rainforest.

behavior

Generally solitary when active at night, but share nests. Undergo a period of genuine obligatory torpor during the austral winter (dry season), accumulating fat stores in the tail prior to becoming inactive.

feeding ecology and diet

Feed mainly on fruit, supplemented with insects and possibly some plant exudates.

reproductive biology

Monogamous. Strictly seasonal breeding, with births and rearing of offspring during the wet season (October–March). Gestation period of about 70 days. Usually two offspring.

conservation status

Not threatened.

significance to humans

Sometimes eaten by humans, but otherwise of little significance.

Western fat-tailed dwarf lemur

Cheirogaleus medius

subfamily

Cheirogaleinae

taxonomy

Cheirogaleus medius É. Geoffroy, 1812, Fort Dauphin, Madagascar.

other common names

French: Petit cheirogale; German: Fettschwanz-Katzenmaki.

physical characteristics

Fur soft and dense; dorsal fur pale silvery gray (sometimes tinged with pale brown); ventral fur creamy white or yellowish white. Eyes surrounded by dark rings and separated by a pale nose stripe. Ears medium-sized and naked, but partially hidden by surrounding fur. Length 7.6 in (19 cm), tail 7.6 in (19 cm); 7 oz (188 g) for males, 6 oz (172 g) for females.

distribution

Occurs throughout the western region of Madagascar, in most forested areas of the south, west, and northwest.

habitat

Deciduous and semiarid forests.

behavior

Undergoes a period of genuine obligatory torpor during the austral winter, accumulating conspicuous fat stores in the tail prior to entering torpor. Generally solitary when active at night, but adults form monogamous pairs with shared nests and home ranges.

feeding ecology and diet

Feeds mainly on fruit, supplemented with insects and plant exudates.

reproductive biology

Monogamous. Strictly seasonal breeding, with births and rearing of offspring during the wet season (October–March). Ovarian cycle length approximately 20 days. Gestation period about 62 days. Usually two offspring, but sometimes three or even four.

conservation status

Not threatened.

significance to humans

Sometimes eaten by humans, but otherwise of little significance.

Gray mouse lemur

Microcebus murinus

subfamily

Cheirogaleinae

taxonomy

Lemur murinus (J. F. Miller, 1777), Madagascar.

other common names

French: Microcèbe gris; German: Grauer Mausmaki.

physical characteristics

Dorsal fur gray or gray-brown; ventral fur white or yellowish white. Dark midline stripe down the back. Pale nose stripe between the eyes, extending almost to the tip of the snout. Ears large, rounded, membranous, and mobile. Length 5.0 in (12.5 cm), tail 5.4 in (13.5 cm); 2 oz (60 g) for both sexes when most active.

distribution

Occurs throughout forested areas of west and south Madagascar.

habitat

Deciduous and semiarid forests, including scrub vegetation.

behavior

Individuals (particularly females) can exhibit intermittent, facultative torpor during the dry season, relying on fat stores accumulated in the tail during the wet season. Commonly described as "solitary," but nevertheless have well-developed social networks with overlapping ranges and shared nests. Daytime sleeping groups containing up to 15 individuals have been reported.

feeding ecology and diet

Rely mainly on fruits and insects, although they also eat other animal prey (e.g., small frogs and chameleons) and plant exudates.

reproductive biology

Polygynous. Strictly seasonal breeding, with births and rearing of offspring during the wet season (October–March), possibly with two successive litters. Ovarian cycle length approximately 50 days. Gestation period about 60 days. Usually two offspring, but occasionally one or three.

conservation status

Not threatened.

significance to humans

Sometimes eaten by humans, but otherwise of little significance.

Red mouse lemur

Microcebus rufus

subfamily

Cheirogaleinae

taxonomy

Microcebus rufus É. Geoffroy, 1834, Madagascar.

other common names

English: Brown mouse lemur; French: Microcèbe roux; German: Roter Mausmaki.

physical characteristics

Dorsal fur dark rufous brown; ventral fur white or yellowish white. Pale stripe between the eyes, extending almost to the tip of the snout. Ears medium-sized, rounded, membranous, and mobile. Length 5 in (12.5 cm), tail 5.6 in (14 cm); 1.5 oz (43 g) for both sexes.

distribution

Occurs throughout the eastern rainforest of Madagascar, from the extreme north to the far south. Extends westward onto the central plateau as well.

habitat

Evergreen rainforest.

behavior

Generally solitary when active at night, but have well-developed social networks involving overlapping ranges and shared nests. Accumulate fat in the tail during the period of high rainfall and use this reserve when less active during the dry season.

feeding ecology and diet

Feed mainly on fruits and insects (notably beetles), but also eat other animal prey (e.g., small frogs and chameleons) and possibly plant exudates.

reproductive biology

Mating system unknown. Strictly seasonal breeding, with births and rearing of offspring during the wet season (October–March), possibly with two successive litters. Ovarian cycle length approximately 50 days. Gestation period about 57 days. Usually two offspring, but occasionally one or three.

conservation status

Not listed by the IUCN, but listed on CITES Appendix I and as endangered by the U.S. Endangered Species Act.

significance to humans

None known.

Coquerel's mouse lemur

Mirza coquereli

subfamily

Cheirogaleinae

taxonomy

Cheirogaleus coquereli (A. Grandidier, 1867), Morondava, Madagascar.

other common names

French: Microcèbe de Coquerel; German: Coquerels-Zwergmaki.

physical characteristics

Dense fur, dorsally light brown to grayish brown, ventrally yellowish gray. Tail darkens along its length, becoming dark brown or black at the tip. Large, naked ears. Nails keeled and sharply pointed. Length 8.5 in (21 cm), tail 13 in (33 cm); 11 oz (304 g) for males, 11.5 oz (326 g) for females.

distribution

Patchy distribution in deciduous forests of Madagascar, occurring in three separate areas of dry forest in the western region.

habitat

Deciduous forests.

behavior

Usually solitary when active at night, but individuals are linked in social networks on the basis of overlapping ranges and shared nests.

feeding ecology and diet

Feed mainly on fruits and insects, but have also been reported to consume sugary secretions produced by bugs of the family Flattidae.

reproductive biology

Polygynous. Strictly seasonal breeding, with birth and rearing of offspring during the wet season (October–March). Gestation period about 89 days. Usually one offspring.

conservation status

Vulnerable.

significance to humans

Sometimes eaten by humans, but otherwise of little significance.

Masoala fork-crowned lemur

Phaner furcifer

subfamily

Phanerinae

taxonomy

Lemur furcifer (Blainville, 1839), Morondava, Madagascar.

other common names

French: Phaner; German: Gabelstreifenmaki; Spanish: Maki ardilla.

physical characteristics

Dorsal fur dark brown; ventral fur creamy. A dark, well-defined stripe runs up most of the back and divides just behind the head into two stripes passing across the otherwise paler crown, becoming continuous with dark eye rings. The face is blunt and the anterior premolars in the upper jaw are enlarged, giving the impression that there are two canine teeth on each side. Ears are large, rounded, and membranous. Tail very bushy; first half similar in color to dorsal fur and other half very dark. Nails on fingers and toes (except big toe) are strongly keeled with pointed tips. Length 9.4 in (23.5 cm), tail 14.2 in (35.5 cm); 16.5 oz (460 g).

distribution

Restricted to the Masoala Peninsula in northeastern Madagascar.

habitat

Evergreen rainforest.

behavior

Usually solitary when active at night, but individuals are linked in social networks through overlapping ranges. Members of a pair maintain vocal contact during the night and typically sleep in the same nest during the day.

feeding ecology and diet

Specialized for gum-feeding from trunks of trees, but insect galleries may also be opened. Main diet is complemented with insects, fruits, and flowers (may be licked rather than ingested).

reproductive biology

There is a tendency towards monogamy, with one adult male and one adult female often occupying a joint territory, but a male may associate with more than one female. Births occur in November–January. Ovarian cycle length about 15 days. Typically gives birth to a single infant. Gestation period unknown.

conservation status

Lower Risk/Near Threatened.

significance to humans

Sometimes eaten by humans, but otherwise of little significance.

Resources

Books

Charles-Dominique, et al., eds. Nocturnal Malagasy Primates. New York: Academic Press, 1980.

Groves, Colin P. The Taxonomy of Primates. Washington, DC: Smithsonian Institution Press, 2001.

Martin, Robert D. Primate Origins and Evolution: A Phylogenetic Reconstruction. New Jersey: Princeton University Press, 1990.

Sussman, Robert W. Primate Ecology and Social Structure. Volume 1: Lorises, Lemurs and Tarsiers. Needham Heights, MA: Pearson Custom Publishing, 1999.

Tattersall, Ian. The Primates of Madagascar. New York: Columbia University Press, 1982.

Periodicals

Atsalis, Sylvia. "Diet of the Brown Mouse Lemur (Microcebus rufus) in Ranomafana National Park, Madagascar." International Journal of Primatology 20 (1999): 193–229.

——. "Seasonal Fluctuations in Body Fat and Activity Levels in a Rain Forest Species of Mouse Lemur (Microcebus rufus)." International Journal of Primatology 20 (1999): 883–910.

Fietz, Joanna. "Monogamy As a Rule Rather Than Exception in Nocturnal Lemurs: The Case of the Fat-tailed Dwarf Lemur, Cheirogaleus medius." Ethology 105 (1999): 259–272.

Fietz, Joanna, and Jürg U. Ganzhorn. "Feeding Ecology of the Hibernating Primate Cheirogaleus medius: How Does It Get So Fat?" Oecologia 121 (1999): 157–164.

Kappeler, Peter M. "Intrasexual Selection in Mirza coquereli: Evidence for Scramble Competition Polygyny in a Solitary Primate." Behavioral Ecological Sociobiology 41 (1997): 115–127.

Marivaux, Laurent, et al. "A Fossil Lemur from the Oligocene of Pakistan." Science 294 (2001): 587–591.

Martin, Robert D. "Adaptive Radiation and Behaviour of the Malagasy Lemurs." Philosophical Transactions of the Royal Society of London Series B 264 (1972): 295–352.

Meier, Bernhard, and Roland Albignac. "Rediscovery of Allocebus trichotis Günther 1875 (Primates) in Northeast Madagascar." Folia Primatologica 56 (1991): 57–63.

Müller, Alexandra E. "A Preliminary Report on the Social Organization of Cheirogaleus medius (Cheirogaleidae; Primates) in North-West Madagascar." Folia Primatologica 69 (1998): 160–166.

——. "Aspects of Social Life in the Fat-tailed Dwarf Lemur (Cheirogaleus medius): Inferences from Body Weights and Trapping Data." American Journal of Primatology 49 (1999): 265–280.

Radespiel, Ute. "Sociality in the Gray Mouse Lemur (Microcebus murinus) in Northwestern Madagascar." American Journal of Primatology 51 (2000): 21–40.

Radespiel, Ute, et al. "Sex-specific Usage Patterns of Sleeping Sites in Grey Mouse Lemurs (Microcebus murinus) in Northwestern Madagascar." American Journal of Primatology 4 (1998): 77–84.

Schmid, Jutta. "Sex-specific Differences in Activity Patterns and Fattening in the Gray Mouse Lemur (Microcebus murinus) in Madagascar." Journal Mammalia 80 (1999): 749–757.

Yoder, Anne D. "Relative Position of the Cheirogaleidae in Strepsirhine Phylogeny: A Comparison of Morphological and Molecular Methods and Results." American Journal of Physical Anthropology 94 (1994): 25–46.

——. "Back to the Future: A Synthesis of Strepsirrhine Systematics." Evolutionary Anthropology 6 (1997): 11–22.

Yoder, Anne D., et al. "Ancient Single Origin for Malagasy Primates." Proceedings of the National Academy of Sciences of the United States of America 93 (1996): 5122–5126.

Robert D. Martin, PhD