Internal fertilization  

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Train wreck at Montparnasse (October 22, 1895) by Studio Lévy and Sons.
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Train wreck at Montparnasse (October 22, 1895) by Studio Lévy and Sons.

In mammals, internal fertilization is done through copulation, which involves the insertion of the penis into the vagina. Some other higher vertebrate animals (most reptiles, most birds, and some fish) reproduce internally, but their fertilization is cloacal.

The union of spermatozoa of the parent organism. At some point, the growing egg or offspring must be expelled. There are three general ways of doing this:

  • Oviparous organisms, including most insects and reptiles, monotremes, and all birds lay eggs that continue to develop after being laid, and hatch later.
  • Viviparous organisms, including almost all mammals (such as whales, kangaroos and humans) bear their young live. The developing young spend proportionately more time within the female's reproductive tract. The young are later released to survive on their own, with varying amounts of help from the parent (s) on the species.

Most species of land animals reproduce by internal fertilization. For example: All reptiles, such as the snake and turtle reproduce by internal fertilizations. Males and females usually have an opening called the cloaca through which semen, urin and feces can be released. During mating, the male and female join their cloacas. The male releases semen into the female's cloaca. The spermatozoe then travel up a canal to reach the ova.




Unless indicated otherwise, the text in this article is either based on Wikipedia article "Internal fertilization" or another language Wikipedia page thereof used under the terms of the GNU Free Documentation License; or on original research by Jahsonic and friends. See Art and Popular Culture's copyright notice.

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