Cheirogaleidaedwarf lemurs and mouse lemurs(Also: fork-marked lemur)

Di­ver­sity

There are 21 species in 5 gen­era in the fam­ily Cheirogalei­dae. As with most Mala­gasy mam­mals, re­cent re­search has re­sulted in the nam­ing of sev­eral new species in re­cent years. These are the small­est lemur species and are all ar­bo­real, noc­tur­nal, and so­cial. They are all sim­i­lar in ecol­ogy, with rel­a­tively re­stricted ranges and some vari­a­tion in diets. (Groves, 1989; Mar­tin, 2003; Nowak and Par­adiso, 1983; Thor­ing­ton and An­der­son, 1984; Vaughan, et al., 2000)

Ge­o­graphic Range

Dwarf and mouse lemurs are re­stricted to forested re­gions of Mada­gas­car. (Mar­tin, 2003; Nowak and Par­adiso, 1983; Vaughan, et al., 2000)

Habi­tat

Dwarf and mouse lemurs are found in forested habi­tats of dif­fer­ent types, in­clud­ing ever­green, de­cid­u­ous, and scrub forests. Mouse lemurs (Mi­cro­ce­bus) are also found in sub­ur­ban and agri­cul­tural areas. Dwarf and mouse lemurs rest dur­ing the day in tree hol­lows or rounded leaf nests in Mi­cro­ce­bus and Mirza species. (Mar­tin, 2003; Nowak and Par­adiso, 1983; Vaughan, et al., 2000)

Phys­i­cal De­scrip­tion

Dwarf and mouse lemurs are the small­est lemurs, from 12 to 27 cm in length and 30 (Mi­cro­ce­bus berthae) to 460 g (Phaner fur­cifer). Pygmy, or Berthe's, mouse lemurs (Mi­cro­ce­bus berthae) are the small­est pri­mates. Cheirogaleids have gray or brown dor­sal pelage and lighter, creamy or yel­low­ish pelage on their ven­tral sur­faces. Some species have bold mark­ings on their faces, such as eye rings or nose stripes. The fur is often thick and woolly. In gen­eral species in east­ern Mada­gas­car (more mesic forests) have red­dish or brown fur and species in west­ern Mada­gas­car (more arid forests) have gray­ish fur. Dwarf and mouse lemurs are char­ac­ter­ized by un­usu­ally long tails, rang­ing from about the length of the body to roughly half again as long; large, thin, and mem­bra­nous ears; and well de­vel­oped fa­cial and carpal vib­ris­sae. They have large, for­ward-fac­ing eyes, re­flect­ing their noc­tur­nal lifestyle, com­pact bod­ies, and long, del­i­cate fin­gers with rounded tips. In many species males are slightly larger than fe­males. (Mar­tin, 2003; Nowak and Par­adiso, 1983; Vaughan, et al., 2000)

Their hind feet have elon­gated cal­ca­neus and nav­ic­u­lar bones. As with other strep­sirhines, they have a dis­tinc­tive " toi­let claw" on the sec­ond digit of their hind feet. Their thumb (pollex) is not as con­spic­u­ously sep­a­rated from the other dig­its as in lemurs; and the third and fourth dig­its of both feet are sim­i­lar in length. (Feld­hamer, et al., 1999; Groves, 1989; Nowak and Par­adiso, 1983; Sza­lay and Dod­son, 1979; Thor­ing­ton and An­der­son, 1984; Vaughan, et al., 2000)

Cra­nially, dwarf and mouse lemurs are de­fined by de­tails of their cra­nial cir­cu­la­tion and bul­lae. The frontal and palatal bones con­tact the orbit in most cheirogaleids. They have the typ­i­cal strep­sirhine tooth comb made up of lower in­cisors and ca­nines, and their den­tal for­mula is 2/2, 1/1, 3/3, 3/3 = 36. In con­trast to lemurs, their upper in­cisors are elon­gate. Hypocones are small are ab­sent on the upper mo­lars. (Feld­hamer, et al., 1999; Groves, 1989; Nowak and Par­adiso, 1983; Sza­lay and Dod­son, 1979; Thor­ing­ton and An­der­son, 1984; Vaughan, et al., 2000)

  • Sexual Dimorphism
  • sexes alike
  • male larger

Re­pro­duc­tion

Some species are gen­er­ally found in monog­a­mous fam­ily groups (Cheirogaleus, Phaner, Mirza). Mi­cro­ce­bus species occur in multi-male, multi-fe­male so­cial groups in which males pur­sue fe­males when they are in es­trous. Males use mat­ing calls dur­ing the time of breed­ing. Fe­males can have mul­ti­ple male mates and give birth to lit­ters with mul­ti­ple pa­ter­nity as a re­sult. Fe­males have dis­tinct es­trous cy­cles. In some species the vagina is sealed with a mem­brane when the fe­male is not in es­trous. A vagi­nal plug forms after cop­u­la­tion in some species. Es­trous is sig­naled by swelling of the vulva. (Mar­tin, 2003; Nowak and Par­adiso, 1983; Vaughan, et al., 2000)

Dwarf and mouse lemurs breed sea­son­ally, gen­er­ally dur­ing the wet sea­son from Oc­to­ber to March. Smaller species can have mul­ti­ple lit­ters in a year, each with 2 to 3 young, larger species give birth to sin­gle off­spring. Ges­ta­tion is from 2 to 3 months and the young are cared for in a nest. (Mar­tin, 2003; Nowak and Par­adiso, 1983; Vaughan, et al., 2000)

Fe­males nurse their young reg­u­larly through­out the day, mak­ing it nec­es­sary for them to re­turn to the nest through­out their night­time for­ag­ing pe­riod. (Mar­tin, 2003)

  • Parental Investment
  • altricial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female

Lifes­pan/Longevity

Dwarf lemurs (Cheirogaleus) have been recorded liv­ing up to 23.2 years old and fork-marked lemurs (Phaner fur­cifer) have been recorded liv­ing up to 25 years in cap­tiv­ity. Longevity in the wild has not been well doc­u­mented and is likely to be shorter than cap­tive lifes­pans.

Be­hav­ior

Dwarf and mouse lemurs are all noc­tur­nal and ar­bo­real. They gen­er­ally for­age on their own, but roost dur­ing the day in small so­cial groups and re-con­nect with other mem­bers of their so­cial groups pe­ri­od­i­cally through­out the night. So­cial or­ga­ni­za­tion varies among species, with some species (Mi­cro­ce­bus, for ex­am­ple) being found in multi-male, multi-fe­male groups and oth­ers (Cheirogaleus, for ex­am­ple) oc­cur­ring in monog­a­mous fam­ily units. Multi-male, multi-fe­male groups are rel­a­tively loosely struc­tured, with in­di­vid­u­als hav­ing over­lap­ping home ranges. Species that occur in rel­a­tively monog­a­mous fam­ily units may co­op­er­ate to de­fend ter­ri­to­ries. Smaller species may be­come tor­pid oc­ca­sion­ally and their body tem­per­a­tures are la­bile, low­er­ing when they sleep and ris­ing when ac­tive. Fat is stored in the tail dur­ing rainy sea­sons to help in­di­vid­u­als make it through dry sea­sons or times of tor­por. Cheirogaleus species in arid habi­tats may aes­ti­vate for up to 6 months. Cheirogaleids get around with bipedal leaps and quadrupedal lo­co­mo­tion on branches. (Mar­tin, 2003; Nowak and Par­adiso, 1983; Vaughan, et al., 2000)

Com­mu­ni­ca­tion and Per­cep­tion

In­di­vid­u­als in so­cial groups com­mu­ni­cate with each other through scent mark­ing and vo­cal­iza­tions. Scent mark­ing in­volves leav­ing urine, feces, and gland se­cre­tions on trees and branches. Vo­cal­iza­tions in­clude con­tact calls, alarm calls, and ter­ri­to­r­ial de­fense calls, most are rel­a­tively high pitched sounds. (Mar­tin, 2003)

Food Habits

Dwarf and mouse lemurs are gen­er­ally om­niv­o­rous, eat­ing fruits, in­sects, nec­tars, plant gums, and oc­ca­sion­ally leaves and small ver­te­brates. Some species spe­cial­ize on por­tions of that diet. For ex­am­ple, Cheirogaleus species eat mainly fruit and Phaner species spe­cial­ize on plant gums and have a well-de­vel­oped tooth comb in the lower jaw for this pur­pose. Most species for­age mainly on the small branches of trees and shrubs below 10 m high, but they also for­age on tree trunks, es­pe­cially Phaner species, which have sharp claws on their dig­its to allow cling­ing to ver­ti­cal sur­faces. Phaner species also have an en­larged cae­cum to help them di­gest plant gums. (Mar­tin, 2003; Nowak and Par­adiso, 1983; Vaughan, et al., 2000)

Pre­da­tion

Preda­tors of cheirogaleids are not re­ported in the lit­er­a­ture, but are likely to in­clude noc­tur­nal preda­tors, such as snakes (Ser­pentes), owls (St­rigi­formes), and fos­sas (Cryp­to­procta ferox). They are noc­tur­nal, cryp­ti­cally col­ored, ar­bo­real, and agile, all help­ing to de­crease their vul­ner­a­bil­ity to preda­tors. (Vaughan, et al., 2000)

  • Anti-predator Adaptations
  • cryptic

Ecosys­tem Roles

Through their fru­givory, cheirogaleids may help to dis­perse seeds. They also im­pact in­sect pop­u­la­tions through pre­da­tion.

  • Ecosystem Impact
  • disperses seeds

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Dwarf and mouse lemurs are too small to be hunted for food to a great ex­tent. They may help to dis­perse seeds in forests and con­trol in­sect pests to some ex­tent. (Mar­tin, 2003; Nowak and Par­adiso, 1983)

  • Positive Impacts
  • controls pest population

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

There are no ad­verse ef­fects of dwarf and mouse lemurs on hu­mans.

Con­ser­va­tion Sta­tus

Most dwarf and mouse lemur species are con­sid­ered "data de­fi­cient" by the IUCN, pri­mar­ily be­cause many species are newly named and poorly un­der­stood. Of the 29 species rec­og­nized by the IUCN, 14 species are data de­fi­cient, 7 are least con­cern, 1 is near threat­ened, 2 are vul­ner­a­ble, and 4 are en­dan­gered. Species con­sid­ered least con­cern are still con­sid­ered po­ten­tially vul­ner­a­ble to habi­tat de­struc­tion and pop­u­la­tions are thought to be in de­cline. Smaller species tend to be more com­mon and wide­spread, larger species tend to have frag­men­tary dis­tri­b­u­tions and are less com­mon, there­fore more threat­ened. Pre­vi­ously, all lemurs were con­sid­ered en­dan­gered, so they are all listed on Ap­pen­dix I of CITES. (IUCN, 2009; Mar­tin, 2003)

Hairy-eared dwarf lemurs (Al­lo­ce­bus tri­cho­tis) were con­sid­ered ex­tinct until they were re­dis­cov­ered in 1989. (Vaughan, et al., 2000)

  • IUCN Red List [Link]
    Not Evaluated

Other Com­ments

There are no Cheirogalei­dae fos­sils, al­though they are known from sub­fos­sil de­posits on Mada­gas­car. An Eocene fos­sil genus from Pak­istan, Bugtile­mur, is con­sid­ered part of Cheirogalei­dae. (Mar­tin, 2003)

Con­trib­u­tors

Tanya Dewey (au­thor), An­i­mal Di­ver­sity Web.

Phil Myers (au­thor), Mu­seum of Zo­ol­ogy, Uni­ver­sity of Michi­gan-Ann Arbor.

Glossary

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

acoustic

uses sound to communicate

agricultural

living in landscapes dominated by human agriculture.

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

arboreal

Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

island endemic

animals that live only on an island or set of islands.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

monogamous

Having one mate at a time.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

omnivore

an animal that mainly eats all kinds of things, including plants and animals

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

suburban

living in residential areas on the outskirts of large cities or towns.

tactile

uses touch to communicate

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

Ref­er­ences

Feld­hamer, G., L. Drick­amer, S. Vessey, J. Mer­ritt. 1999. Adap­ta­tion, Di­ver­sity, and Ecol­ogy. Boston: WCB Mc­Graw-Hill.

Groves, C. 1989. A The­ory of Human and Pri­mate Evo­lu­tion. Ox­ford: Ox­ford Sci­ence Pub­li­ca­tions, Claren­don Press.

IUCN, 2009. "IUCN Redlist of Threat­ened Species" (On-line). Ac­cessed July 27, 2009 at http://​www.​iucnredlist.​org/​.

Mar­tin, R. 2003. Dwarf lemurs and mouse lemurs (Cheirogalei­dae). Pp. 35-45 in M Hutchins, A Evans, J Jack­son, D Kleiman, J Mur­phy, D Thoney, eds. Grz­imek An­i­mal Life En­cy­clo­pe­dia, Vol. 14, 2nd Edi­tion. De­troit: Gale Group.

Nowak, R., J. Par­adiso. 1983. Walker's Mam­mals of the World, Fourth edi­tion. Bal­ti­more, Lon­don: John Hop­kins Uni­ver­sity Press.

Sza­lay, F., E. Dod­son. 1979. Evo­lu­tion­ary His­tory of the Pri­mates. New York: Aca­d­e­mic Press.

Thor­ing­ton, R., S. An­der­son. 1984. Pri­mates. Pp. 187-216 in S An­der­son, J Jones, eds. Or­ders and Fam­i­lies of Re­cent Mam­mals of the World. New York: John Wiley and Sons.

Vaughan, T., J. Ryan, N. Czaplewski. 2000. Mam­mal­ogy, Fourth Edi­tion. Philadel­phia: Saun­ders Col­lege Pub­lish­ing.

de Ma­g­alhães, J. 2009. "The an­i­mal age­ing and longevity data­base" (On-line). Ac­cessed July 27, 2009 at http://​genomics.​senescence.​info.