Gestation period
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.
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[edit] Duration
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 645 days.[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.
[edit] Gestation periods
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This section does not cite any references or sources. Please help improve this section by adding citations to reliable sources. Unsourced material may be challenged and removed. (April 2009) |
[edit] See also
[edit] References
- Gestation, Incubation, and Longevity of Selected Animals
- David Crystal, The Cambridge Factfinder Cambridge: Cambridge University Press, 1998 (84).
[edit] Notes
- ^ "Gestation period". McGraw-Hill's AccessScience Encyclopedia of Science & Technology Online. McGraw-Hill. http://www.accessscience.com/abstract.aspx?id=288400&referURL=http%3a%2f%2fwww.accessscience.com%2fcontent.aspx%3fid%3d288400.
- ^ a b c "gestation". Britannica - The Online Encyclopedia. Encyclopædia Britannica. http://www.britannica.com/EBchecked/topic/232124/gestation.
- ^ "Average Animal Gestation Periods and Incubation Times". MSN Encarta. Microsoft. Archived from the original on 2009-10-31. http://www.webcitation.org/5kwpsKDKF.
- ^ "Does gestation vary by ethnic group? A London-based study of over 122000 pregnancies with spontaneous onset of labour". International Journal of Epidemiology. http://ije.oxfordjournals.org/cgi/content/full/33/1/107.
- ^ 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)
- ^ 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)
- ^ 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)
- ^ 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)
- ^ 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)
- ^ 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)
- ^ 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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