WikiPortallus: Lemur.html

Lemurs make up the infraorder Lemuriformes and are members of a group of primates known as prosimians. The term "lemur" is derived from the Latin word lemures, meaning "spirits of the night" or "ghosts". This likely refers to their large, reflective eyes and the wailing cries of some species (the Indri in particular). The term is generically used for the members of the four lemuriform families, but it is also the genus of one of the lemuriform species, the Ring-tailed Lemur (Lemur catta). The two so-called flying lemur species, that are also called colugos, are not lemurs or even primates.

Biology

Lemurs are primates found naturally only on the island of Madagascar and some smaller surrounding islands, including the Comoros (where they were likely introduced by humans). Fossil evidence indicates that they reached Madagascar after it broke away from mainland Africa, possibly by "rafting" across the ocean on large clumps of vegetation.² While their ancestors were displaced in the rest of the world by monkeys, apes, and other primates, the lemurs were safe from competition on Madagascar and differentiated into a number of species. These range in size from the tiny 30 gram (1 oz) Pygmy Mouse Lemur to the 10 kilogram (22 lb) Indri. The larger species, some of which weighed up to 240 kg³, have all become extinct since humans settled on Madagascar, and since the early 20th century the largest lemurs reach about 10 kilograms (22 lbs). Typically, the smaller lemurs are nocturnal, while the larger ones are diurnal.

The small cheirogaleoids are generally omnivores, eating a variety of fruits, flowers and leaves (and sometimes nectar) as well as insects, spiders and small vertebrates. The remainder of the lemurs, the lemuroids are primarily herbivores, although some species supplement their diet with insects.

Except for the Indri, all lemurs have long tails that they use for communication with each other and balance when leaping between trees. They have opposable thumbs and long toes adapted for gripping tree branches. Lemurs have nails rather than claws on all digits except the second toe of each hind foot, which has a "toilet claw" for grooming. All lemur species have a tapetum, the reflective layer over the retina that causes their eyes to shine at night.³ Lemurs are thought to have limited color vision.³ Lemurs depend heavily on the sense of smell and have large nasal cavities and moist noses.³

Unlike most other primates, lemur species that live in groups have a Matriarchal society (i.e., females are dominant over males). Most lemur species are arboreal and traverse the canopy by vertical clinging and leaping or quadrupedalism, with the exception of the Ring-Tailed Lemur, which spends most of its time on the ground.

Hybrids may occur between different species of lemur. In The variation of animals and plants under domestication Charles Darwin noted: "Several members of the family of Lemurs have produced hybrids in the Zoological Gardens."⁴

Endangered species

Most lemurs are listed as endangered or threatened species. Many species have gone extinct in the last centuries, mainly due to habitat destruction (deforestation) and hunting. Conservation of lemurs in Madagascar is a high priority, but the country's poor economic situation and the lemurs' limited range make it an uphill battle. There are 85 living lemur species accounted for in current publications,⁵⁶⁷⁸, with more documentation currently awaiting publication.

Classification

As shown here, the four families of lemurs are split into two superfamilies. The Cheirogaleidae have a pedal structure similar to the other strepsirrhine families and the haplorrhines, suggesting they split off from the other lemurs first. As such, the Cheirogaleoidea are a sister clade to the Lemuroidea.

Female dominance

Female dominance is very rare as a social structure in mammals, and is only observed consistently in hyenas and lemurs.⁹ It occurs when all adult males exhibit submissive behavior to adult females in social settings. These social settings are usually related to feeding, grooming, and sleeping site priority. Interestingly, lemurs do not exhibit sexual dimorphism (males and females are the same in physical appearance and size).¹⁰ Therefore, male deference is a social construct and not a matter of size or strength.

Female social dominance was first observed in the Ring-tailed Lemur (Lemur catta).¹¹ Since then, many, but not all, species of lemurs have been found to demonstrate female social dominance including the Crowned Lemur (Eulemur coronatus) and the Gray Mouse Lemur (Microcebus murinus).^{citation needed}

Hypotheses for the Evolution of Female Dominance

Since these original proposals, scientists like Peter Kappeler have modified and integrated other ideas, but there is no single hypothesis that can fully explain female social dominance in lemurs at this time and all three are likely to play a role.

In popular culture

Lemurs are not as commonly seen in popular culture settings as other primates, but their popularity has grown recently due to greater exposure.

References

^ ^a ^b Groves, C. (2005-11-16). Wilson, D. E., and Reeder, D. M. (eds). ed.. Mammal Species of the World (3rd edition ed.), Johns Hopkins University Press. pp. 111-121. ISBN 0-801-88221-4, http://www.bucknell.edu/msw3/browse.asp?id=12100003.
^ ""What's A Lemur?"". Retrieved on 2006-04-19.
^ ^a ^b ^c ^d Strier, Karen B. (2000). Primate Behavioral Ecology. Boston: Allyn and Bacon. pp. 49.
^ Darwin, C. (1868). The variation of animals and plants under domestication. 2 (1st edition ed.), London: John Murray. pp. 153. ISBN 1421270730, http://darwin-online.org.uk/content/frameset?viewtype=side&itemID=F877.2&pageseq=167.
^ Mittermeier, Russell A., Konstant, William R., Hawkins, Frank, Louis, Edward E., and Langrand, Olivier (2006). Lemurs of Madagascar (2nd edition ed.), Conservation International, http://www.madagascar-library.com/r/544.html. Retrieved on 29 October 2006.
^ Andriaholinirina, N., Fausser, J., Roos, C., Rumpler, Y., et al (February 2006). "Molecular phylogeny and taxonomic revision of the sportive lemurs (Lepilemur, Primates)". BMC Evolutionary Biology 6: 17. doi:10.1186/1471-2148-6-17.
^ Edward E. Louis, Jr., Shannon E. Engberg, Runhua Lei, Huimin Geng, Julie A. Sommer, Richard Randriamampionona, Jean C. Randriamanana, John R. Zaonarivelo, Rambinintsoa Andriantompohavana, Gisele Randria, Prosper, Boromé Ramaromilanto, Gilbert Rakotoarisoa, Alejandro Rooney, and Rick A. Brenneman (2006). "Molecular and morphological analyses of the sportive lemurs (Family Megaladapidae: Genus Lepilemur) reveals 11 previously unrecognized species" (PDF). Texas Tech University Special Publications (49): 1–49, http://www.nsrl.ttu.edu/publications/opapers/specpubs/SP49.pdf.
^ Olivieria, G., Zimmermannb, E., Randrianambininab, B., Rassoloharijaonab, S., Rakotondravonyb, D., Guschanskia, K., Radespiela, U. (2006-10-26). "The ever-increasing diversity in mouse lemurs: three new species in north and northwestern Madagascar". Molecular Phylogenetics and Evolution 43: 309. doi:10.1016/j.ympev.2006.10.026.
^ Digby, LI and Kahlenberg, SM (2002). "Female dominance in blue-eyed black lemurs". Primates 43: 191-199.
^ Engelhardt, NV, Kappeler, PM, and Heistermann, M (2000). "Androgen levels and female social dominance in Lemur catta". Proc. R. Soc. Lond. B 267: 1553-1539.
^ Jolly, A (1966). Lemur Behavior. Chicago: University of Chicago Press.
^ "Female Dominance and Maternal Invesment in Strepsirhine Primates". The American Naturalist 135: 473-488. 1990.

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