Gestation period
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It has been suggested that this article be merged into Pregnancy_(mammals)#Gestational_duration_by_species. (Discuss) Proposed since October 2013. |
For mammals the gestation period is the time in which a fetus develops, beginning with fertilization and ending at birth.[1] The duration of this period varies between species.
Duration[edit]
For most species, the amount a fetus grows before birth determines the length of the gestation period. Smaller species normally have a shorter gestation period than larger animals.[2] For example, a cat's gestation normally takes 58–65 days while an elephant's takes nearly 2 years (21 months).[3] However, growth does not necessarily determine the length of gestation for all species, especially for those with a breeding season. Species that use a breeding season usually give birth during a specific time of year when food is available.[2]
Various other factors can come into play in determining the duration of gestation. For humans, male fetuses normally gestate several days longer than females and multiple pregnancies gestate for a shorter period.[2] Ethnicity may also lengthen or shorten gestation.[4] In dogs there's a positive correlation between gestation time and a small litter size.[clarification needed][citation needed]
Gestational periods[edit]
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This section does not cite any references (sources). (April 2009) |
See also[edit]
References[edit]
- Gestation, Incubation, and Longevity of Selected Animals
- David Crystal, The Cambridge Factfinder Cambridge: Cambridge University Press, 1998 (84).
- Online animal encyclopedia
- Study finds wide range in pregnancy length
Notes[edit]
- ^ "Gestation period". McGraw-Hill's AccessScience Encyclopedia of Science & Technology Online. McGraw-Hill.
- ^ a b c "gestation". Britannica - The Online Encyclopedia. Encyclopædia Britannica.
- ^ "Average Animal Gestation Periods and Incubation Times". MSN Encarta. Microsoft. Archived from the original on 2009-10-31.
- ^ "Does gestation vary by ethnic group? A London-based study of over 122000 pregnancies with spontaneous of labour". International Journal of Epidemiology.
- ^ Paris Hill Farm. "Alpacas 101". Retrieved 2012-07-14.
- ^ Northwest Alpacas. "Alpaca Q&A". Retrieved 2012-07-14.
- ^ University of Michigan. "Ursus Americanus". Retrieved 2013-01-16.
- ^ a b c d e f Anamnese en lichamelijk onderzoek bij gezelschapsdieren, A.Rijnberk, F.J.van Sluis, 2nd print, Bohn Stafleu van Loghum, 2005, (Current Dutch veterinary examination study book for small domestic mammals)
- ^ The Laboratory Rat , 2nd Edition, Eds. Mark A. Sucklow, Steven H. Weisbroth, and Craig L. Franklin. Page 151.
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