Lemur

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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 are not lemurs, nor are they even primates.

 

Contents

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 kg[3], 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

Female (top) and male (bottom) black lemurs in their natural habitat in Madagascar
Female (top) and male (bottom) black lemurs in their natural habitat in Madagascar

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,[5][6][7][8], with more documentation currently awaiting publication.

One of the foremost lemur research facilities is the Duke Lemur Center.

 

Classification

Thermographic image of a Ring-tailed Lemur in the morning sun.
Thermographic image of a Ring-tailed Lemur in the morning sun.

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.

  • ORDER PRIMATES[1]
    • Suborder Strepsirrhini: non-tarsier prosimians
      • Infraorder Lemuriformes
        • Superfamily Cheirogaleoidea
          • Family Cheirogaleidae: dwarf and mouse lemurs

        • Superfamily Lemuroidea

          • Family Lemuridae: lemurs
          • Family Lepilemuridae: sportive lemurs
          • Family Indriidae: woolly lemurs, sifakas, and allies

      • Infraorder Chiromyiformes: Aye-aye
      • Infraorder Lorisiformes: galagos (bushbabies) and lorises

    • Suborder Haplorrhini: tarsiers, monkeys and apes

 

Female dominance

Female dominance is a very rare social structure in mammals 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 ring-tailed lemurs (Lemur catta) by Alison Jolly in 1966[11]. Since then, many, but not all, species of lemurs have been found to demonstrate female social dominance including the crowned lemur (Lemur coronatus) and the gray mouse lemur (Microcebus murinus).

Hypotheses for the Evolution of Female Dominance

There are three basic proposals for the evolution of female dominance[12]:

  1. The Energy Conservation Hypothesis: males subordinate to females to conserve energy for the intense male-male competition experienced during lemur’s very short breeding season
  2. Male behavioral strategy: males defer as a parental investment because it ensures more resources in the harsh unpredictable climate of Madagascar for the female, and thus, the male’s future offspring.
  3. Female behavioral strategy: dominance helps females deal with the unusually high reproductive demands; they prevail in more social conflicts because they have more at stake in terms of fitness.

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 pop culture settings as other primates, but their popularity has grown recently due to greater exposure.

  • The comic strip Dilbert by Scott Adams featured a strip comparing managers to drunken lemurs. In 2007, an employee at Catfish Bend Casino was fired for posting the strip at his office. Adams subsequently spoofed the real life event with another series of strips in which Wally is fired when office surveillance cameras catch him posting the anti-management comic on the wall.
  • The film Mr. Magorium's Wonder Emporium features a lemur that is produced by a magic book when Molly Mahoney (Natalie Portman) asks it for a lolipop.
  • The novella Ghost of Chance by William S. Burroughs, set in Madagascar, initially focuses on a character named Captain Mission, who looks after and cares for lemurs. The book is described on the back cover of the 1995 edition as "an important story about environmental devastation."
  • Raw Dog Screaming Press has published a Tom Bradley novel entitled Lemur, about a would-be serial killing busboy who works in a restaurant which has a lemur mascot. The cover of the book features a ring-tailed lemur holding a meat cleaver behind its back and leering in a sinister manner.
  • A Ring-tailed Lemur starred in the 1997 movie Fierce Creatures written by John Cleese.
  • Zoboomafoo, an educational PBS Kids television program, features a Coquerel's Sifaka who is also the show's namesake.
  • The Disney film Dinosaur (2000) features sifakas raising a dinosaur hatchling.
  • In the television program Fat Actress, Kirstie Alley keeps a pet lemur who is never seen but referenced in conversations; a recurring gag involves the proper preparation of yams for its meals.
  • Madagascar, a computer-animated film produced by DreamWorks Animation in 2005, prominently features a group of singing and dancing lemurs.
  • The Katurran Odyssey, a book written by David Michael Wieger and created and illustrated by Star Wars creature designer Terryl Whitlatch, includes a ring-tailed lemur protagonist and several other lemur characters.
  • In the Nickelodeon animated series Avatar: The Last Airbender, Aang keeps a 'winged lemur' named Momo for a pet. Momo mostly resembles a Verreaux's Sifaka, although his appearance was actually based on a Ring-Tailed Lemur mixed with a Spotted bat.
  • The American rock group The Mars Volta used a lemur in their logos, and one is used as the principal character in the video for their single Televators[1]
  • Lemurcon is a roughly annual late summer/early fall get-together of lemur enthusiasts at the Duke Lemur Center in North Carolina. Very roughly, this can be traced to the Usenet alt.fan.lemur mailing list.
  • Lemur Street, a twenty-episode series focused on two groups of Ring-tailed Lemurs in Madagascar.
  • The New York Academy of Sciences recently published a Podcast about the Madagascar! exhibit at the Bronx Zoo. The exhibit prominently features lemurs and in the Podcast, Helen Crowley discusses their presence and behavior. The Podcast can be listened to here

 

References

  1. ^ a b Groves, C. (2005-11-16). in Wilson, D. E., and Reeder, D. M. (eds): Mammal Species of the World, 3rd edition, Johns Hopkins University Press, 111-121. ISBN 0-801-88221-4. 
  2. ^ ""What's A Lemur?"". Retrieved on 2006-04-19.
  3. ^ a b c d Strier, Karen B. (2000). Primate Behavioral Ecology. Boston: Allyn and Bacon, 49. 
  4. ^ Darwin, C. (1868). The variation of animals and plants under domestication, 1st edition 2, London: John Murray, 153. ISBN 1421270730. 
  5. ^ Mittermeier, Russell A., Konstant, William R., Hawkins, Frank, Louis, Edward E., and Langrand, Olivier (2006). Lemurs of Madagascar, 2nd edition, Conservation International. Retrieved on 2006-10-29. 
  6. ^ 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. 
  7. ^ 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. 
  8. ^ 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. 
  9. ^ L.I. Digby and S.M. Kahlenberg, 2002. “Female dominance in blue-eyed black lemurs” Primates 43: 191-199.
  10. ^ N.V. Engelhardt, P.M. Kappeler, and M. Heistermann, 2000. “Androgen levels and female social dominance in Lemur catta” Proc. R. Soc. Lond. B. 267: 1553-1539.
  11. ^ A Jolly 1966 "Lemur Behavior" University of Chicago Press, Chicago
  12. ^ A.L. Young, A.F. Richard, and L.C. Aiello, 1990 "Female Dominance and Maternal Invesment in Strepsirhine Primates" The American Naturalist 135: 473-488

 

External links

 
 
Duke Lemur Center Lots of photographs, information, and research programs.
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