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User:Kosigrim/L-age

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Lions’ age

File:LionNose65%.jpg
Lions' age could be estimated using nose coloration. On the top right corner a nose of a 3 years-old Serengeti male. The estimated age of the male in focus is approximately 8.

Population

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Lions (Panthera leo) are the only social cat species characterized to date[1][2][3] with remarkably egalitarian female behavior and unique voluntary system of communal cub rearing[4]. Their populations appear to be sensitive and in accelerating decline due to several factors such as reproductive output (pregnancy rate), delayed maturity, lower survival, competition for food, incidence of infectious disease and overall human activity (including revenge or trophy hunting)[5][6][7][8]. Few carnivores have suffered more dramatic reductions of range and population sizes than the lion. Before humans colonized the Western Hemisphere, the lion was perhaps the most widespread terrestrial mammal, ranging from southern Africa to northern Europe, across all of Asia and North America, extending south as far as Peru[9][10]. It has been show that the lions' population at Ngorongoro Crater can be seriously endangered by infectious disease even with a large stable food supply and no real threats from competing species[11]. Old population models have assumed that population trends could be predicted from data on survival and reproduction of lions. However, a more complete understanding of population dynamics can only be achieved by taking into account the impact of social and family structure on the population as a whole[12].

Trophy hunting

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Lions are generally perceived by Africans as having a negative value, but trophy (tourist) hunting is a management tool that can provide positive economic value to local people[13]. For example, in 1992, trophy hunting in the Selous Game Reserve generated 1.28 million dollars for the Tanzanian government, of which 0·96 million dollars were returned to wildlife conservation[14]. Lions' hunting industry has always been based on arbitrary quota system that is difficult to enforce[15][16][17]. There is low risk of setting excessive trophy hunting quotas in areas where it is possible to estimate the lions' population size[18]. A simulation model suggested that quotas could become inappropriate to the conservation of lions[19]. Lions' breeding biology and social behaviour (such as infanticide[20]) could inform a threshold-age criterion that would minimize the adverse effects from killing of sexually mature males. Young adult males should be excluded from trophy hunting so females would be seasonably impregnated and vulnerable offspring be protected by their fathers.

Maturity

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Lions' reproduction can take place in any month of the year; gestation is 110 days, and the interbirth interval is about 2 years[21]. Male lions reach maturity at about 2.5 years of age and live to a maximum of ~15 years in the wild[22]. The lion’s mane reaches full size at about 4 years[23], and peak reproductive ability is effectuated by ~8 years[24].

Nose indicator

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The most consistent age indicator for the Serengeti/Ngorongoro lions is the amount of dark pigmentation in the tip of the nose, which becomes progressively freckled with age. Lions’ noses continue to darken until they become 9 years old, while individual variation of the darkening could be observed[25]. For example, the noses of 5 years old males are 50% black (see example on the right).

See also

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References

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  1. ^ Leyhausen P. (1979) Cat behaviour: the predatory and social behaviour of domestic and wild cats. Garland STPM Press, New York
  2. ^ Caro TM, (1989) Determinants of associality in fields. In Comparative socioecology: the behavioral ecology of humans and others mammals. Edited by V. Staden and RA Foley. Blackwell Press, Oxford, UK, pp 41-74
  3. ^ Caro TM, (1994) Cheetahs of the Serengeti Plains: group living in an asocial species. University of Chicago Press. Chicago.
  4. ^ Packer C., et al., Science (2001) 293, pp690-3
  5. ^ Woodroffe, R., 2000. Predators and people: using human densities to interpret declines of large carnivores. Animal Conservation 3, 165–173.
  6. ^ Nowell J. & Jackson P. (1996) Wild cats: status survey and conservation plan. IUCN, Gland, Switzerland
  7. ^ Loveridge, A.J. 2004. Does Sport Hunting Impact Lion Populations? A Case Study from Zimbabwe. Abstract of talk given to a conference on Man and Mammals-Conflicts in Nature, Mammals Trust UK, 21 February 2004
  8. ^ Macdonald, D.W. and A.J. Loveridge. 2003. The Lion King: Is His Throne Secure? Lecture given on 7 October 2003 at the Zoological Society of London. Macdonald and Loveridge are with Oxford University's Wildlife Conservation Research Unit. Reported in Oxford Blueprint (University of Oxford), Volume 4, Issue 2, October 2003, Also reported in Kirby, A. 2003. Africa's 'shocking' lion loss. BBC News Online, 7 October 2003, http://news.bbc.co.uk/1/hi/sci/tech/3171380.stm, viewed 17 April 2004.
  9. ^ Kurt en, B., Anderson, A., 1980. Pleistocene Mammals of North America. Columbia University Press, New York
  10. ^ Turner, A., Anton, M., 1997. The Big Cats and Their Fossil Relatives:An Illustrated Guide to Their Evolution and Natural History. Columbia University Press, New York.
  11. ^ Bernard M. Kissui and Craig Packer Top-down population regulation of a top predator: lions in the Ngorongoro Crater. Proc. R. Soc. Lond. B (2004)
  12. ^ Packer C. et al., Science (2005) 307, pp.390-3
  13. ^ Chardonnet, P. 2002. Conservation of the African lion: Contribution to a status survey. International Foundation for the Conservation of Wildlife, France and Conservation Force, USA
  14. ^ Creel S. & Creel NM, African Journal of Ecology (1997) 35 (2), 83–93
  15. ^ Leader-Williams, N., Kayera, J. A. & Overton, G. L. Tourist Hunting in Tanzania (IUCN Species Survival publication no. 14, Gland, Switzerland, 1996)
  16. ^ Caro, T.M. et al. The impact of tourist hunting on large mammals in Tanzania: an initial assessment. Afr. J. Ecol. 36, 321–329 (1998)
  17. ^ Sutherland,W. J. Sustainable exploitation: a review of principles and methods.Wildl. Biol. 7, 131–140 (2001)
  18. ^ Hillborn, R. &Walters, C. J. Quantitative Fisheries Stock Assessment: Choice,Dynamics and Uncertainty (Chapman & Hall, New York, 1992)
  19. ^ Whitman K., Starfield AM, Quadling HS. and C. Packer., Nature (2004) 428, pp.175-8
  20. ^ Slotow, R., Van Dyk, G., Poole, J., Page, B. & Klocke, A. Older bull elephants control young males. Nature 408, pp.425–426 (2000)
  21. ^ . C. Packer, A. E. Pusey, Anim. Behav. 31, 334 (1983)
  22. ^ Schaller, G. B. The Serengeti Lion (Univ. Chicago Press, Chicago, 1972)
  23. ^ West, P. M. & Packer, C. Sexual selection, temperature and the lion’s mane. Science 297, 1339–1343 (2002)
  24. ^ Packer, C. et al. in Reproductive Success (ed. Clutton-Brock, T. H.) 363–383 (Univ. Chicago Press, Chicago, 1988)
  25. ^ Whitman K., Starfield AM, Quadling HS. and C. Packer., Nature (2004) 428, pp.175-8

Lions Category:Mammals of Africa Category:Conservation Category:Wildlife

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