Mouse lemur
Microcebus

TAXONOMY

Suborder: Strepsirrhini
Infraorder: Lemuriformes
Superfamily: Cheirogaleoidea
Family: Cheirogaleidae
Genus: Microcebus
Species: M. berthae, M. bongolavensis, M. danfossi, M. griseorufus, M. jollyae, M. lehilahytsara, M. mamiratra, M. mittermeieri, M. murinus, M. myoxinus, M. ravelobensis, M. rufus, M. sambiranensis, M. simmonsi, M. tavaratra

Other names: M. berthae: Madame Berthe's mouse lemur, pygmy mouse lemur, Berthe's mouse lemur; microcèbe de Berthe (French); tsidy (Malagasy); M. bongolavensis: Bongolava mouse lemur; M. danfossi: Danfoss' mouse lemur; M. griseorufus: rufous-grey mouse lemur, red-and-grey mouse lemur; microcèbe gris-roux (French); tsidy (Malagasy); M. jollyae: Jolly's mouse lemur; M. lehilahytsara: Goodman's mouse lemur; microcèbe de Goodman (French); Goodman's mausmaki (German); M. mamiratra: Claire's mouse lemur; M. mittermeieri: Mittermeier's mouse lemur; M. murinus: grey mouse lemur, lesser mouse lemur; microcèbe murin, cheirogale mignon, cheirogale nain, petit microcèbe (French); grauer mausmaki, maus zwergmaki (German); tsidy, koitsiky, titlivaha, pondiky (Malagasy); maki ratón, maki ratón gris, makisratone (Spanish); grâ musmaki, mindre muslemur, pygmémusmaki (Swedish); M. myoxinus: mouse lemur, pygmy mouse lemur; microcèbe pygmée (French); tsidy, malajira (Malagasy); M. ravelobensis: Lac Ravelobe mouse lemur, golden-brown mouse lemur; microcèbe doré (French); tsidy (Malagasy); guldbrun musmaki (Swedish); M. rufus: rufous mouse lemur, brown mouse lemur, russet mouse lemur; microcèbe roux (French); brauner mausmaki (German); antsidy mena, tsidy, tsitsidy, tsitsihy, kandrandra (Malagasy); maki ratón (Spanish); brun musmaki, röd musmaki, rödbrun muslemur (Swedish); M. sambiranensis: Sambirano mouse lemur; microcèbe du Sambirano (French); tsidy, tsitsihy, vokimbahy (Malagasy); M. simmonsi: Simmon's mouse lemur; M. tavaratra: northern rufous mouse lemur, Tavaratra mouse lemur; microcèbe roux du nord (French); tsidy (Malagasy).

The taxonomy of the genus Microcebus is extremely fluid, with ten new species described since 2000 (Rylands 2007). Groves (2005) lists 8 species in the genus, however since his publication, seven new species have been described and are all here included as full species (Kappeler et al. 2005; Andriantompohavana et al. 2006; Louis et al. 2006; Olivieri et al. 2007). However, M. lokobensis is not considered a species due to its potential synonymy with M. mamiratra (Olivieri et al. 2007). Some researchers are hesitant to accept all new forms of mouse lemur and think that the number of new species may be exaggerated (Tattersall 2007; Sylvia Atsalis pers. comm.). This is likely to remain the case until the situation is made clearer through further research (Tattersall 2007). Generally, the best researched species to date are M. murinus, M. rufus and M. ravelobensis and less or little is known about the other species.

MORPHOLOGY

Mouse lemurs have a combined head, body and tail length of less than 27 cm (10.6 in) making them the most diminutive of the primates (Mittermeier et al. 2006; Ankel-Simons 2007). Among the mouse lemurs, the superlative goes to M. berthae, which is the world's smallest primate (Dammhahn & Kappeler 2005). Mouse lemurs can be divided up into two groups based on their general overall fur coloration. M. murinus and M. griseorufus are generally grayish, while M. rufus, M. ravelobensis, M. myoxinus, M. berthae, M. sambiranensis, M. tavaratra, M. lehilahytsara, M mittermeieri, M. jollyae, and M. simmonsi are overall generally reddish (Olivieri et al. 2007). However, it is difficult to distinguish certain species apart purely by observation, and such species are discriminated from one another based on genetic differences and/or body measurements (Olivieri et al. 2007). There is some intra-specific variation in coloration in some species which further complicates the situation, and in some cases specimens that are very different in coloration have turned out to be the same species when investigated through other means (Heckman et al. 2006; Olivieri et al. 2007).

All mouse lemurs have a white strip between the eyes (Olivieri et al. 2007). M. lehilahytsara is bright maroon, with a whitish ventrum and an orangeish back, head, and tail (Kappeler et al. 2005). M. rufus has a grayish brown back with a black stripe, reddish arms, grayish-white ventrum and a red-brown head. M. mittermeieri is red-brown or rust colored on its head and back with some orange on its limbs with a white-brown ventrum. M. jollyae is reddish-brown on its back and head and has a grey ventrum. M. simmonsi has dark reddish or orange brown fur on its back, arms, and head and has a grayish white ventrum (Louis et al. 2006). The color of the head of M. bongolavensis and M. danfossi varies with the individual but the back is orangish maroon, and the ventrum is creamy-white (Olivieri et al. 2007). M. mamiratra has a light reddish-brown back and tail, with a white or cream colored ventrum (Andriantompohavana et al. 2006). M. tavaratra has a reddish head, dark brownish back, and a whitish-beige ventrum. M. sambiranensis has a reddish back with a vaguely defined stripe and a whitish-beige ventrum (Rasoloarison et al. 2000). M. ravelobensis has a golden-brown or mottled-red back, with a yellow to white ventrum and a brown tail (Zimmermann et al. 1998; Rasoloarison et al. 2000). M. murinus has a grayish-brown to brownish-gray back, a beige or gray ventrum, and a stripe down the back. M. myoxinus has a red-brown back with a dorsal stripe and red-brown head markings. M. berthae is reddish, with a dorsal line and a head that is brighter than the rest of its coloration. M. griseorufus has a gray back with a cinnamon-brown stripe, reddish markings on its head, and a white ventrum (Rasoloarison et al. 2000).

Recorded head and body length averages are 9.0-9.1 cm (3.5-3.6 in) (M. lehilahytsara), 12.7 cm (5.0 in) (M. ravelobensis), 12.6 cm (5.0 in) (M. tavaratra), 12.3 cm (4.8 in) (M. griseorufus), 9.2 cm (3.6 in) (M. berthae), 11.7 cm (4.6 in) (M. sambiranensis), 12.4 cm (4.8 in) (M. myoxinus), 12.9 cm (5.1) (M. murinus) (Rasoloarison et al. 2000; Kappeler et al. 2005; Andriantompohavana et al. 2006). The average body lengths of M. rufus and M. mamiratra are 8.6 cm (3.4 in) and 9.4 cm (3.7 in) respectively (Andriantompohavana et al. 2006). Recorded body lengths of single individuals are 9.8 cm (3.9 in) (M. simmonsi), 8.2 cm (3.2 in) (M. mittermeieri), and 5.3 cm (2.1 in) (M. jollyae) (Louis et al. 2006).

The body mass of mouse lemurs is seasonally variable, but published body weight averages range from 39.6-48 g (1.4-1.7 oz) (M. lehilahytsara), 51.8-71.7 g (1.8-2.5 oz) (M. ravelobensis), 51.7-61.1 g (1.8-2.2 oz) (M. tavaratra), 43.7g (1.5 oz) (M. rufus), 44.1 g (1.6 oz) (M. mittermeieri), 43.7-62.6 g (1.5-2.2 oz) (M. griseorufus), 60.8 g (2.1 oz) (M. mamiratra), 30.6 g (1.1 oz) (M. berthae), 61.3 g (2.2 oz) (M. jollyae), 40.4-44.1 g (1.4-1.6) (M. sambiranensis), 45.2-49.0 g (1.6-1.7 oz) (M. myoxinus), 53.2-65.5 g (1.9-2.3 oz) (M. murinus) (Rasoloarison et al. 2000; Kappeler et al. 2005; Andriantompohavana et al. 2006; Olivieri et al. 2007; Atsalis 2008). A single adult male M. simmonsi individual weighed 77.8 g (2.7 oz) (Louis et al. 2006).

M. myoxinus is not sexually dimorphic in body size but shows a seasonal swap of dimorphism between males and females, with males consistently heavier than females during the reproductive season with the opposite true the rest of the year (Schwab 2000). A similar seasonal shift in sexual dimorphism of mass is seen in M. murinus (Eberle & Kappeler 2002). Body mass is seasonally variable in M. murinus as well (Fietz 1999). M. rufus do not show significant differences in body mass between the sexes (Sylvia Atsalis pers. comm.; Atsalis 2008).

Neither M. berthae nor M. murinus show sexual dimorphism of body size (Fietz 1999; Dammhahn & Kappeler 2005). M. myoxinus are not sexually dimorphic in body size but show a seasonal swap of dimorphism between males and females, with males consistently heavier than during the reproductive season with the opposite true the rest of the year (Schwab 2000). A similar seasonal shift in sexual dimorphism of mass is seen in M. murinus (Dberle & Kappeler 2002).

All mouse lemurs generally move quadrupedally; including running, but also leaping short distances, and some movement on the ground (Martin 1973). However, the usual mode of travel is quadrupedally on branches (Schmidt 2005). Some locomotor differences between mouse lemur species have been discovered. M. ravelobensis, for example, moves through its environment by leaping although M. murinus is predominantly quadrupedal; the differences are probably due to different body morphology, as well as different preferred forest strata (Zimmermann et al. 1998).

In captivity, mouse lemurs have lived over 18 years (Weigl 2005).

RANGE

CURRENT RANGE MAPS (IUCN REDLIST):
Microcebus berthae | Microcebus bongolavensis | Microcebus danfossi | Microcebus griseorufus | Microcebus jollyae | Microcebus lehilahytsara | Microcebus mamiratra | Microcebus mittermeieri | Microcebus murinus | Microcebus myoxinus | Microcebus ravelobensis | Microcebus rufus | Microcebus sambiranensis | Microcebus simmonsi | Microcebus tavaratra

Mouse lemurs, like all other lemurs, are restricted to the island-nation of Madagascar off of the eastern shores of Africa. Between the reddish forms and grayish forms, reddish species (M. rufus, M. ravelobensis, M. myoxinus, M. berthae, M. sambiranensis, M. tavaratra, M. lehilahytsara, M. mittermeieri, M. jollyae, and M. simmonsi) tend toward small spatial distributions while grayish forms (M. murinus and M. griseorufus) have larger distributions (Olivieri et al. 2007). However, species distributions require further investigation and are incompletely known (Kappeler & Rasoloarison 2003).

M. bongolavensis is found between the Sofia River in the north and the Mahajamba River in the south in the northwestern part of Madagascar. The distribution of this species is delimited by the central Malagasy plateau in the east and by the Mozambique Channel in the west. M. danfossi can be found just north of M. bongolavensis, delimited by the Sofia River in the south and the Maevarano River in the north. The eastern and western limits are as in M. bongolavensis (Olivieri et al. 2007). M. rufus is reported from Ranomafana National Park and Mantadia National Parks in southeastern and eastern Madagascar respectively. M. mittermeieri has only been found at the Anjanaharibe-Sud Special Reserve in northern Madagascar, whereas M. jollyae as only be found at the Mananjary and Kianjavato localities in eastern Madagascar. M. simmonsi has only been found in the Betampona Special Reserve and in the Zahamena National Park in northeastern Madagascar (Louis et al. 2006). M. mamiratra is known only from the island of Nosy Be, off the northwest coast of Madagascar (Andriantompohavana et al. 2006). M. ravelobensis is only found in the Ankarafantiska Nature Reserve in northwest Madagascar (Zimmermann et al. 1998). M. tavaratra is only known from the Ankarana Special Reserve in far northern Madagascar (Rasoloarison et al. 2000). M. sambiranensis is only known from Manongarivo Special Reserve in northern Madagascar (Rasoloarison et al. 2000). While not well defined, the M. murinus distribution is wide, roughly stretching in the west of Madagascar from Ankarafantsika National Park south to the Onilahy River, with another pocket of inhabitance in the southeastern tip of the island in the Mandena Conservation Zone (Mittermeier et al. 2006). M. myoxinus is found between the Tsiribihina River and the Soalala Peninsula in northwestern Madagascar. M. berthae is found around the Kirindy/CFPF Forest and perhaps further north in western Madagascar. M. griseorufus inhabits the area around Toliara in southwestern Madagascar north to Lamboharana and may range further south and southeast (Rasoloarison et al. 2000). M. lehilahytsara has only been found at Andasibe and Mantadia National Park in eastern Madagascar (Kappeler et al. 2005). Finally, M. simmonsi has been found only at the Betampona Special Reserve and in the Zahamena National Park in eastern Madagascar (Louis et al. 2006).

HABITAT

In general, all types of forest habitat on Madagascar are called home by mouse lemurs, including forests altered by humans (Kappeler & Rasoloarison 2003; Radespiel 2006). Types of forest in which different species of mouse lemur are found include evergreen littoral, dry deciduous, transitional, gallery, arid spiny, sub-arid thorn scrub, thick scrub, spiny, mangrove, sub-humid, partially evergreen, lowland, lowland and montane tropical humid, and mosaic. They have also been found in old eucalyptus plantations with undergrowth (compiled from the literature by Radespiel 2006). Some species are found in several habitat types, whereas others are found in only one type, although data on restricted habitat use can sometimes be the result of a lack of research (Radespiel 2006; for habitat use by species see Radespiel 2006:214). Mouse lemurs can be found from sea level up to almost 2000 m (reviewed by Radespiel 2006).

At one long-term study site of M. rufus at Ranomafana National Park in southeastern Madagascar, average annual rainfall was 448.5 cm (176.6 in) with average monthly lows of 13.1°C (55.6°F) and average monthly highs of 22.5°C (72.5°F) (Atsalis 2008). However, monthly variation in precipitation was seen at this site, with a wet season (December-March) during which more rain fell than during the dry season (April-November). At a different study site of sympatric M. ravelobensis and M. murinus in northwestern Madagascar at the Ampijoroa Forestry Reserve, average monthly temperatures ranged from 16°C (60.8 °F) (June-July) to 37°C (98.6 °F) (October-November) with an overall annual average temperature of 27°C (80.6°F) (Rendigs et al. 2003).

ECOLOGY

Omnivorous food choice is characteristic of all species of mouse lemur and generally, diets are diverse and change depending on the season (Radespiel 2006; Atsalis 2008). For example, foods that are consumed by M. murinus include insect secretions, arthropods, small vertebrates, gum, fruit, flowers, nectar, and also leaves and buds (literature compiled by Radespiel 2006; Radespiel et al. 2006; Lahann 2007). Gums, but also sugary secretions of insects, are extremely important in mouse lemur diets, especially the diets of mouse lemurs living in dry forests (Atsalis 2008). The diets of M. rufus and M. ravelobensis are both similar to the diet of M. murinus (Gould & Sauther 2007). At the only long-term study site of M. rufus diet at the Ranomafana National Park, the species was highly frugivorous, consuming an estimated minimum of 64 kinds of fruit but also members of 9 different orders of insect (Atsalis 1999; 2008). In the same study of mouse lemur diet (M. rufus) to date, fruit of the mistletoe (Bakerella) was found to be a diet staple for the species, and was a keystone food used to get through times of resource scarcity (Atsalis 2008). At this study site, a seasonal change in diet is seen at the end of the rainy season and the early ensuing dry season when there is a significant increase in the number of types and quantities of fruits eaten. Data on the diet of M. berthae is limited, but preliminary data indicates that the species eats mostly animal matter and insect secretions (Dammhahn & Kappeler 2006). Also, where more than one species of mouse lemur are sympatric, diets can be considerably different between the species (Dammhahn & Kappeler 2006; Atsalis 2008).

All mouse lemurs are strictly nocturnal (Schilling et al. 1999; Kappeler & Rasoloarison 2003; Atsalis 2008). In general, mouse lemur activity levels, metabolism, body temperature, and body mass all vary throughout the year and are perhaps viewed best through the lens of an annual cycle which is driven by changes in day length (Atsalis 2008). Mouse lemur seasonal weight fluctuations are also related to changes in daylight duration (Perret & Aujard 2001). Two types of torpor are seen in mouse lemurs; daily and seasonal. Daily torpor functions in energy management, while seasonal torpor functions to help mouse lemurs survive yearly periods of resource scarcity. However, not all mouse lemurs hibernate, and in fact, there appears to be no clear pattern at all. Some individuals of the same species and even the same population hibernate while others do not, and different populations of the same and different species at different locations show varying patterns of torpor (Schmid 2001; reviewed by Atsalis 2008). During torpor and hibernation, metabolic rate as well as body temperature decline, and can reduce the metabolism of the mouse lemur by up to 90% and the body temperature to nearly that of the environment around it (Ortmann et al. 1997; Schmid 2000; 2001).

At one study site in western Madagascar, two different types of torpor are practiced by M. murinus; daily torpor averaging 9.3 hours punctuated by activity, and long-term torpor, which may last for weeks (Schmid 2000). Long-term torpor in M. rufus has lasted between 6-24 weeks (Atsalis 2008). There are also seasonal changes in body weight, with all species gaining weight during the rainy season and losing weight during the dry season (summarized by Radespiel 2006). For example, during the austral winter (May-June) M. murinus and M. rufus begin fattening themselves, gaining body weight as well as increasing the volume of the tail (Petter-Rousseaux 1980; Atsalis 2008). Individuals who enter seasonal torpor lose more weight than those that do not (Radespiel 2006). After a period of long-term torpor, mouse lemurs will have lost all of the preceding weight gain (Atsalis 2008).

Home ranges in M. berthae average 0.049 km² (0.02 mi²) (M) and 0.025 km² (0.01 mi²) (F) (Dammhahn & Kappeler 2005). In M. murinus, home range averages are 0.032 km² (0.01 mi²) (M) and 0.018 km² (0.007 mi²) (F) (Pagès-Feuillade 1988). M. murinus, M. ravelobensis and M. berthae home ranges of both sexes often overlap with those of several other individuals and are usually stable (Pagès-Feuillade 1988; Fietz 1995; Radespiel 2000; Eberle & Kappeler 2002; 2004; Weidt et al. 2004; Dammhahn & Kappeler 2005; Génin 2008). In addition, home ranges of M. griseorufus expand during the rainy season (Génin 2008). The nightly path of M. berthae averages 4470 m (14665.4 ft) (M) and 3190 m (10465.9 ft) (F) (Dammhahn & Kappeler 2005).

Mouse lemurs are often found living sympatrically with other primates. For example, at Ranomafana National Park in southeastern Madagascar, M. rufus is a member of a primate community that also includes Avahi laniger, Cheirogaleus major, Daubentonia madagascariensis, Eulemur fulvus, Eulemur rubriventer, Hapalemur aureus, Hapalemur griseus, Prolemur simus, Varecia variegata, Lepilemur sp., and Propithecus diadema (Atsalis 1998). In a given habitat, more than one species of mouse lemur can live in sympatry, as is the case with M. murinus and M. ravelobensis in northwestern Madagascar, M. murinus and M. berthae in western Madagascar and M. murinus and M. griseorufus in southern Madagascar and M. murinus and M. myoxinus in western Madagascar as examples (Radespiel et al. 2003b; Schwab & Ganzhorn 2004; Mittermeier et al. 2006). Aggression has been seen between sympatric mouse lemurs and dwarf lemurs (Atsalis 2008).

M. murinus prefers to sleep in holes in trees while the other species of mouse lemur use tree holes as well as a variety of other sleeping site options (Schwab 2000; Radespiel et al. 2003b; Radespiel 2006). When living in sympatry, M. murinus prefers tree holes while M. ravelobensis sleeps on branches, lianas, and leaves; a difference that is attributable to inter-species competition (Radespiel et al. 2003b). M. berthae sleeps alone in thick vegetation (Schwab 2000). In the dry season, over a dozen individuals of M. murinus have been found in a single tree hole sleeping site (Rasoazanabary 2006).

Possible and potential predators of mouse lemurs include a variety of nocturnal viverrids, mongooses, and domestic dogs as well as several different types of raptor (reviewed in Goodman et al. 1993; Atsalis 1998). Snakes are also predators of mouse lemurs and have been seen attacking M. murinus (Richard 1978; Eberle & Kappeler 2008). In wild M. murinus, several individuals were observed to mob and even bite a Malagasy tree boa (Sanzinia madagascariensis) that was attacking an adult male, permitting its escape (Eberle & Kappeler 2008). The Madagascar long-eared owl and the Madagascar harrier-hawk both prey on mouse lemurs (Goodman et al. 1991; Karpanty & Goodman 1999). The red owl (Tyto soumagnei) is a predator of the northern rufous mouse lemur (M. tavaratra) (Cardiff & Goodman 2008). In fact, predation can be quite severe, with estimates at Beza Mahafaly, southern Madagascar assigning a 25% loss each year in the entire M. murinus population exclusively to owl predation (Goodman et al. 1993).

Content last modified: February 11, 2009

Written by Kurt Gron. Reviewed by Sylvia Atsalis.

Cite this page as:
Gron KJ. 2009 February 11. Primate Factsheets: Mouse lemur (Microcebus) Taxonomy, Morphology, & Ecology . <http://pin.primate.wisc.edu/factsheets/entry/mouse_lemur/taxon>. Accessed 2011 April 28.