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Fat-tailed Dwarf Lemur (Cheirogaleus medius)


MORPHOLOGY:
The mean adult body mass for the fat-tailed dwarf lemur varies from 142 grams in November to 217 grams in March, corresponding to loses and gains associated with hibernation (Hladik et al., 1980). Like the greater dwarf lemur, Cheirogaleus major, the legs are longer than the arms, but the fat-tailed dwarf lemur is smaller than the greater dwarf lemur. This species builds up fat reserves in the tail to use during hibernation (Harcourt and Thornback, 1990). This species has a pelage color which is light or silver gray with rosy or brownish tints on the dorsal side and is paler on the ventral side being in color from light brown to white (Tattersall, 1982). There are dark maroon or black rings surrounding the eyes with the interorbital area and cheeks being pale (Tattersall, 1982). The face is light gray or brown in color (Tattersall, 1982). This species has two pair of mammae, one pectoral and one inguinal (Tattersall, 1982). The ears of the fat-tailed dwarf lemur are naked (Tattersall, 1982).

RANGE:
The fat-tailed dwarf lemur is found in Western and Southern Madagascar in the dry forests along the coast. This species is found from the Bay of Narinda to Fort-Dauphin (Tattersall, 1982). This species lives in both primary and secondary forests (Harcourt and Thornback, 1990). This species is found in the Nature Reserves of Ankarafantsika and Andohahela, the Special Reserves of Andranomena, Beza Mahafaly, and Ankarana, and the Private Reserves of Berenty and Analabe (Harcourt and Thornback, 1990).

ECOLOGY:
The fat-tailed dwarf lemur shows seasonality in its diet (Hladik et al., 1980). In November the main part of the diet is nectars and fruit, whereas in December-February this species mainly eats fruits and invertebrates and small vertebrates (Hladik et al., 1980). Among the flowers eaten for nectar are the boy flower, Delonix floribunda and Baudouina fluggeiformis (Hladik et al., 1980). Some of the species of fruit eaten include: Operculicarya gummifera, Grewia glandulosa, Strychnos decussata, and Diospyros aculeata (Hladik et al., 1980). This species will also the fruit from Poupartia sylvatica and Berchemia discolor (Scharfe and Schlund, 1996). The most common invertebrate eaten were coleopterans (beetles) (Hladik et al., 1980). The fat-tailed dwarf lemur has also been found to consume gums and the tender parts of plants (Hladik et al., 1980). This species is nocturnal and it will become active right after dusk (Foerg and Hoffmann, 1982). During the austral winter this species hibernates from 6 to 8 months out of the year (Hladik et al., 1980). During hibernation 3 to 5 individuals will share a nest hole, piling up on one another and separated by wet decaying wood (Hladik et al., 1980). The fat-tailed dwarf lemur will emerge from the hibernation holes usually in November when the rains first begin (Hladik et al., 1980). First year fat-tailed dwarf lemurs stay active longer during their first year so as to be able to grow more, not having to compete with their parents for food, so the first hibernation is not as long for the young (Hladik et al., 1980).

LOCOMOTION:
The fat-tailed dwarf lemur is an arboreal quadruped that is not an agile leaper (Fleagle, 1988).

SOCIAL BEHAVIOR:
When this species hibernates, which lasts six to eight months in the winter, many members will huddle together into one nest. This species has a monogamous breeding system based on that the home ranges for adults and offspring overlap and the adult pair was found to sleep in the same nest hole a third of the time (Muller, 1998); the pairs will remain together for 3 years, except if one dies (Fietz, 1999). The adults will share sleeping sites with subadults and that year's infants (Muller, 1998; Fietz, 1999). Both parents will guard the newborns, keeeping them warm, and protecting them from harm (Fietz, 1999). When the male is absent in assisting the female in raising of the offspring, the young will usually die (Fietz, 1999). Males will usually come out of hibernation, or torpor, early in order to secure a home range with adequate resources for his family group (Muller, 1999). The social system for this species can be described to be a dispersed family group (Muller, 1998). It was once thought that species was polygynous, but based on the evidence this species shows more characteristics with being monogamous. Fietz (1999) suggests that parental care is the driving force behind monogamous living in this species.

VOCAL COMMUNICATION:
narrow-band whistles: This call has a constant frequency and occurs in a series (Stanger, 1995). This call occurs between the frequencies of 8 and 19 kHz (Stanger, 1989). This call functions as an advertisement call and the male will also emit this call when sniffing the female's genital area (Stanger, 1995). This call is also heard as a response to a disturbance and in agonistic situations (Stanger, 1995). The constant frequency of this call may reflect the inconspicious way of life for this species (Stanger, 1989); this call is difficult to localize and an individual would not want to draw attention from predators to itself when it is advertising itself to other conspecifics (Stanger, 1989).

frequency-modulated whistles: This call occurs in the ultrasonic range, inaudible to the human ear (Stanger, 1995). This call first starts out at 25 kHz then drops gradually and levels off at 15 kHz (Cherry et al., 1987). Infants and males approaching and being approached by a female will emit this call (Stanger, 1995). This call also occurs during playlike behavior and has been referred to as a whine (Cherry et al., 1987).

rolling call: This call consists of a short series of pulses that occur below the 5 kHz frequency range (Stanger, 1995). This call is heard during nasogenital contacts and also functions as a submissive signal (Stanger, 1995).

grunt: This call is made up of a series of short broad-band pulses (Stanger, 1995). This call functions as a threat call and also occurs during agonistic interactions (Stanger, 1995). Sometimes an individual calling will lunge forward in an attempt to bite (Petter and Charles-Dominique, 1979).

contact call: This call is high in pitch and consists of plaintive squeaks (Petter and Charles-Dominique, 1979). This emitted by the infant with its mouth closed when it wants to attract the attention of its mother (Petter and Charles-Dominique, 1979). This is also heard during allogrooming in adults (Petter and Charles-Dominique, 1979).

OLFACTORY COMMUNICATION:
fecal marking: This is where an individual will drag defecation during locomotion leaving behind feces which are cylindrical and 10 centimeters in length (Schilling, 1980). These feces are trampled as the individual moves and also urination occurs (Schilling, 1980). This functions as a territorial marker and occurs most often during the period of activity, during the austral summer (Schilling, 1980). This behavior is stereotyped and can occur as early as six weeks of age (Schilling, 1980).

VISUAL COMMUNICATION:

TACTILE COMMUNICATION:

REPRODUCTION:
This species has either twins or triplets which are born around December or January. The female’s vagina increases in the pink color to tell the male that she is undergoing estrus and ready for copulation, this generally occurring between September and October. Mating for this species begins in November, right after emergence from hibernation (Hladik et al., 1980).

REFERENCES:
Burton, F. 1995. The Multimedia Guide to the Non-human Primates. Prentice-Hall Canada Inc.

Cherry, J.A., Izard, M.K., and Simons, E.L. 1987. Description of ultrasonic vocalizations of the mouse lemur (Microcebus murinus) and the fat-tailed dwarf lemur (Cheirogaleus medius). American Journal of Primatology. Vol. 13, 181-185.

Fietz, J. 1999. Monogamy as a rule rather than exception in nocturnal lemurs: the case of the fat-tailed dwarf lemur, Cheirogaleus medius. Ethology. Vol. 105, 259-272.

Fleagle, J. G. 1988. Primate Adaptation and Evolution. Academic Press.

Foerg, R. and Hoffmann, R. 1982. Seasonal and daily activity changes in captive Cheirogaleus medius. Folia Primatologica. Vol. 38, 259-268.

Harcourt, C. and Thornback, J. 1990. Lemurs of Madagascar and the Comoros. The IUCN Red Data Book. IUCN, Gland, Switzerland and Cambridge, U.K.

Hladik, C.M., Charles-Dominique, P., and Petter, J.J. 1980. Feeding strategies of five nocturnal prosimians in the dry forest of the West coast of Madagascar. in Nocturnal Malagasy Primates: Ecology, Physiology, and Behavior. eds. P. Charles-Dominique, H.M. Cooper, A. Hladik, C.M. Hladik, E. Pages, G.F. Pariente, A. Petter-Rousseaux, A. Schilling, and J.J. Petter. Academic Press: New York.

Muller, A.E. 1998. A preliminary report on the social organisation of Cheirogaleus medius (Cheirogaleidae; Primates) in North-west Madagascar. Folia Primatologica. Vol. 69, 160-166.

Muller, A.E. 1999. Paternal investment in the monogamous fat-tailed dwarf lemur (Cheirogaleus medius) in northwestern Madagascar. American Journal of Physical Anthropology. Suppl. 28, 207.

Petter, J.J. and Charles-Dominique, P. 1979. Vocal communication in prosimians. in The Study of Prosimian Behavior. eds. G.A. Doyle and R.D. Martin. Academic Press: New York.

Scharfe, F. and Schlund, W. 1996. Seed removal by lemurs in a dry deciduous forest of Western Madagascar. Primate Report. Vol. 46-1, 295-304.

Schilling, A. 1980. Seasonal variation in the fecal marking of Cheirogaleus medius in simulated climatic conditions. in Nocturnal Malagasy Primates: Ecology, Physiology, and Behavior. eds. P.Charles-Dominique, H.M. Cooper, A. Hladik, C.M. Hladik, E. Pages, G.F. Pariente, A. Petter-Rousseaux, A. Schilling, and J.J. Petter. Academic Press: New York.

Stanger, K.F. 1989. A comparative approach to the organization of vocal signals in nocturnal prosimians. Human Evolution. Vol. 4 (2-3), 181-185.

Stanger, K.F. 1995. Vocalizations of some cheirogaleid prosimians evaluated in a phylogenetic context. in Creatures of the Dark: The Nocturnal Prosimians. eds. L. Alterman, G.A. Doyle, and M.K. Izard. Plenum Press: New York.

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

Last Updated: October 6, 2003.
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