Cheirogaleus medius, E. Geoffroy Saint-Hilaire, 1812

Russell A. Mittermeier, Anthony B. Rylands & Don E. Wilson, 2013, Cheirogaleidae, Handbook of the Mammals of the World – Volume 3 Primates, Barcelona: Lynx Edicions, pp. 28-65 : 60-61

23.

Fat-tailed Dwarf Lemur

Cheirogaleus medius

French: Petit Chirogale / German: Fettschwanzmaki / Spanish: Lémur enano de cola gruesa

Other common names: Lesser Dwarf Lemur, Spiny Forest Dwarf Lemur, Western Fat-tailed Dwarf Lemur

Taxonomy. Cheirogaleus medius E. Geoffroy Saint-Hilaire, 1812 ,

Madagascar, Tsidsibon River.

In his 2000 revision of the genus, C. P. Groves considered populations from the tropical dry lowland forests and spiny forest regions of south-western Madagascar to be a distinct species and resurrected the name C. adipicaudatus used by A. Grandidier in 1868. In its morphology, this taxon was said to be similar to C. medius , but with less contrasting colors and a tail that was longer than the head-body length. Groves examined specimens from three southern Madagascarsites: Tahiky, Tolagnaro (= Fort-Dauphin), and an unnamed location 170 km east of Toliara (= Tuléar), most likely representing a collection in dry spiny forest to the west of Tolagnaro. Presence of C. adipicaudatus in the region of Tolagnaro was not supported by a study conducted by A. Hapke and coworkers in 2005, whose findings indicated instead the presence of three other Cheirogaleus species from that region ( C. crossleyi , C. major , and C. medius ). It may be that the features on which this species was differentiated from C. medius characterize only a particular population ofrestricted distribution. In any case, we follow the 2009 study of L. Groeneveld and colleagues in considering C. adipicaudatus as a synonym of C. medius . Groeneveld found five terminal clades within C. medius . This species is currently considered monotypic, but some or all of these clades, which may turn out to be distinct species.

Distribution. W, NE & SE Madagascar in the S spiny forest, E to the evergreen humid forest of Sainte-Luce, 40 km NE of Tolagnaro in the extreme SE; also in Petriky and Mandena, the Lavasoa-Ambatotsirongorongo Mountains (W of Tolagnaro), in the Tolagnaro region in the SE, in the Bay of Pasandava in the NW, in the Sahamalaza Peninsula, as far NW as Ankarana region, and in Bekaraoka and Sambava in the NE; possibly also in the Daraina area of the NE.

Descriptive notes. Head—body 17-23 cm,tail 19-27 cm; weight 135 g (varies seasonally; heavierjust before the onset of seasonal torpor). The Fat-tailed Dwarf Lemur is one of the smaller members of the genus Cheirogaleus . The upper body is a light frosted fawngray, with a broad but indistinct brown dorsal stripe. The underside is broadly creamy or yellowish (somewhat more yellow toward the midline), with a partial white collar around the throat, sharply marked, extending well up on the sides of the neck. There is a white median facial stripe, and eye-rings are dark brown. Hands and feet are white, and ears are naked. Tail length is roughly equal to head-body length.

Habitat. Primary and secondary dry deciduous, gallery, evergreen humid, and transitional subhumid forests.

Food and Feeding. Fruits, flowers, seeds, and the tender parts of plants are dietary staples of the Fat-tailed Dwarf Lemur , with invertebrates being eaten in small amounts and small vertebrates taken on occasion. Gums, nectar, and insect excretions are also consumed. Flowers are eaten for nectar, including the boy flower ( Delonix floribunda, Fabaceae ) and Baudowinia flueggeiformis ( Fabaceae ). Types of fruit eaten include Operculicarya gummifera ( Anacardiaceae ), Grewia glandulosa ( Malvaceae ), Strychnos decussata ( Loganiaceae ), Diospyros aculeata ( Ebenaceae ), Poupartia silvatica ( Anacardiaceae ), and Berchemia discolor ( Rhamnaceae ). The most common invertebrates eaten are coleopterans (beetles). The Fat-tailed Dwarf Lemur shows seasonality in its feeding preferences; the main part of the diet in November consists of nectar and fruits, whereas fruits and animal matter are mainly eaten from December to February.

Breeding. Despite the monogamous family structure of the mating system of the Fattailed Dwarf Lemur , ¢.40% of offspring is fathered by other males. Mating begins right after emergence from torpor. The female’s vulva is closed except during estrus, at which pointit pinkens and swells. Estrus occurs about every 20 days during the breeding season in September—November, and males fight over available females. Average gestation is remarkably short, a mere 61-64 days. One to four (usually two) offspring are born in December—January. Newborn are already covered with fur, and their eyes are open. Males and females participate in raising the young. Full sexual maturity is reached during the second year of life. Longevity record in captivity is 18 years.

Activity patterns. The Fat-tailed Dwarf Lemur is nocturnal and arboreal. Daylight hours are spent in tree holes, with up to five individuals occupying a single shelter. The Fat-tailed Dwarf Lemur is one of the only primate species known to undergo extended seasonal periods of torpor, akin to hibernation. Its common English name stems from its ability to store fat in the tail as a nutritional reserve during such periods. Because individuals enter this torpid state during the austral winter, they are typically not seen from May to mid-September. During sleep or periods of physiological torpor, they roll themselves up in a tight ball.

Movements, Home range and Social organization. Individuals defend home ranges of 1-2 ha. Small family groups consist of the reproductively active pair and their offspring from one or two breeding seasons. Individuals of both sexes disperse from their natal range, and local populations a few kilometers apart can vary greatly in density and sex ratio. The Fat-tailed Dwarf Lemuris sympatric with the Greater Dwarf Lemur ( C. major ) and Crossley’s Dwarf Lemur ( C. crossleyi ) over parts of its distribution. Density estimates of the Fat-tailed Dwarf Lemur are 40-400 ind/km?.

Status and Conservation. CITES Appendix I. Classified as Least Concern on The [UCN Red List. Although the Fat-tailed Dwarf Lemur is apparently widespread and abundant at present, the discovery of new taxa within its formerly broad range will no doubt affect its overall status. It is reported to occur in at least seven national parks (Andohahela, Ankarafantsika, Baie de Baly, Sahamalaza-Iles Radama, Tsimanampetsotsa, Tsingy de Namoroka, and Zombitse-Vohibasia), five special reserves (Andranomena, Ankarana, Bemarivo, Beza-Mahafaly, and Maningoza), Kirindy Forest (part of the Menabe-Antimena Protected Area), Daraina (Loky-Manambato Protected Area), and Sainte-Luce Reserve. It is uncertain whether this or another species of Cheirogaleus occurs in Tsingy de Bemaraha National Park.

Bibliography. Dausmann, Ganzhorn & Heldmaier (2000), Dausmann, Glos et al. (2004), Feistner & Schmid (1999), Fietz (1999a, 1999b, 2003), Fietz & Ganzhorn (1999), Fietz et al. (2000), Foerg (1982b), Fredstedt et al. (2007), Ganzhorn & Kappeler (1996), Goodman (2003), Goodman & Langrand (1996a), Groeneveld et al. (2009), Groves (2000a, 2001), Hapke et al. (2005), Harcourt & Thornback (1990), Hladik et al. (1980), Mittermeier, Louis et al. (2010), Mittermeier, Tattersall et al. (1994), Mller (1998, 1999a, 1999b), Nicoll & Langrand (1989), O'Connor et al. (1986), Pages & Petter-Rousseaux (1980), Petter (1978), Scharfe & Schlund (1996), Schilling (1980).

Figures

20. Coquerel’s Giant Mouse Lemur (Mirza coquereli), 21. Northern Giant Mouse Lemur (Mirza zaza), 22. Hairy-eared Dwarf Lemur (Allocebus trichotis)

Distribution. W, NE & SE Madagascar in the S spiny forest, E to the evergreen humid forest of Sainte-Luce, 40 km NE of Tolagnaro in the extreme SE; also in Petriky and Mandena, the Lavasoa-Ambatotsirongorongo Mountains (W of Tolagnaro), in the Tolagnaro region in the SE, in the Bay of Pasandava in the NW, in the Sahamalaza Peninsula, as far NW as Ankarana region, and in Bekaraoka and Sambava in the NE; possibly also in the Daraina area of the NE.