Document Detail


Lemur traits and Madagascar ecology: coping with an island environment.
MedLine Citation:
PMID:  10601983     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The last decade's lemur research includes successes in discovering new living and extinct species and learning about the distribution, biogeography, physiology, behavior, and ecology of previously little-studied species. In addition, in both the dry forest and rain forest, long-term studies of lemur demography, life history, and reproduction, have been completed in conjunction with data on tree productivity, phenology, and climate. Lemurs contrast with anthropoids in several behavioral features, including female dominance, targeted female-female aggression, lack of sexual dimorphism regardless of mating system, sperm competition coupled with male-male aggression, high infant mortality, cathemerality, and strict seasonal breeding. Hypotheses to explain these traits include the "energy conservation hypothesis" (ECH) suggesting that harsh and unpredictable climate factors on the island of Madagascar have affected the evolution of female dominance, and the "evolutionary disequilibrium hypotheses" (EVDH) suggesting that the recent megafauna extinctions have influenced lemurs to become diurnal. These hypotheses are compared and contrasted in light of recent empirical data on climate, subfossils, and lemur behavior. New data on life histories of the rain forest lemurs at Ranomafana National Park give further support to the ECH. Birth seasons are synchronized within each species, but there is a 6-month distribution of births among species. Gestation and lactation lengths vary among sympatric lemurs, but all lemur species in the rain forest wean in synchrony at the season most likely to have abundant resources. Across-species weaning synchrony seen in Ranomafana corroborates data from the dry forest that late lactation and weaning is the life history event that is the primary focus of the annual schedule. Lemur adaptations may assure maximum offspring survival in this environment with an unpredictable food supply and heavy predation. In conclusion, a more comprehensive energy frugality hypothesis (EFH) is proposed, which postulates that the majority of lemur traits are either adaptations to conserve energy (e.g., low basal metabolic rate (BMR), torpor, sperm competition, small group size, seasonal breeding) or to maximize use of scarce resources (e.g., cathemerality, territoriality, female dominance, fibrous diet, weaning synchrony). Among primates, the isolated adaptive radiation of lemurs on Madagascar may have been uniquely characterized by selection toward efficiency to cope with the harsh and unpredictable island environment.
Authors:
P C Wright
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  American journal of physical anthropology     Volume:  Suppl 29     ISSN:  0002-9483     ISO Abbreviation:  Am. J. Phys. Anthropol.     Publication Date:  1999  
Date Detail:
Created Date:  2001-01-26     Completed Date:  2001-02-22     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0400654     Medline TA:  Am J Phys Anthropol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  31-72     Citation Subset:  IM    
Affiliation:
Department of Anthropology, State University of New York at Stony Brook, Stony Brook, New York 11794, USA.
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MeSH Terms
Descriptor/Qualifier:
Adaptation, Physiological
Animals
Anthropology, Physical
Behavior, Animal*
Diet
Ecology
Energy Metabolism
Evolution
Female
Fossils
Geography
Lemur*
Madagascar
Male
Reproduction
Seasons
Social Behavior*

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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