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Fertilization which takes place inside the female body is called Internal fertilization in animals is done through the following different ways:〔Research conducted by Patricia Adair Gowaty. Reported by 〕 * Copulation, which involves the insertion of the penis or other intromittent organ into the vagina (in most mammals) or to the cloaca in monotremes, most reptiles, some birds, the amphibian tailed frog and some fish, the disappeared dinosaurs, as well as in other non-vertebrate animals. * Cloacal kiss, which consists in that the two animals touch their cloacae together in order to transfer the sperm of the male to the female. It is used in most birds and in the tuatara, that don't have an intromittent organ. * Via spermatophore, a sperm-containing cap placed by the male in the female's cloaca. Usually, the sperm is stored in spermathecae on the roof of the cloaca until it is needed at the time of oviposition. It is used by some salamander and newt species, by the arachnida, some insects and some mollusks. 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, dinosaurs and all birds lay eggs that continue to develop after being laid, and hatch later.〔Thierry Lodé (2001). ''Les stratégies de reproduction des animaux'' (Reproduction Strategies in Animal Kingdom). Eds. Dunod Sciences. Paris.〕 * 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) of the species.〔Blackburn, D. G. (2000). Classification of the reproductive patterns of amniotes.:" Herpetological Monographs", 371-377.〕 * Ovoviviparous organisms, like the garter snake, most Vipers, and the Madagascar hissing cockroach, have eggs (with shells) that hatch as they are laid, making it resemble live birth. Most species of land animals reproduce by internal fertilization. For example: All reptiles, such as the snake and turtle reproduce by internal fertilization. Males and females usually have an opening called the cloaca through which semen, urine and feces can be released. During mating, the male and female join their cloacas. The male releases semen into the female's cloaca. The spermatozoa then travel up a canal to reach the ova. ==See also== *Insemination 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「internal fertilization」の詳細全文を読む スポンサード リンク
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