Viviparous animalsPosted on May 18, 2018 - Last modified: September 8, 2018
Viviparous animals are all those animals that gestate in the female's womb, there is a great difference between viviparous animals and oviparous. All mammalian animals are viviparous, except for the echidna and the platypus, which are oviparous mammals. There are also certain species of lizards and amphibians that are mammals. There are some species that are ovovivíparas like the shark.
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Viviparous animals are mainly characterized in that the embryo is gestated inside the female's womb and they have a type of sexual reproduction (The male expels the sperm and this joins the ovum thus giving rise to gestation, thus creating the fetus).
The young grow in the placenta, where they receive the nutrients and oxygen necessary to grow healthy. In the placenta they remain alive until the female calves. There is an exception for marsupials, which once hatched can remain in the mother's pouch for weeks.
The gestation and its period of time is different for each species, and there are up to 30 days, such as rabbits, even rhinos or whales, which can take up to a year and a half.
Viviparous animals and their classification
We can classify them according to their need to be nourished or not according to the placenta.
They are the vast majority of mammalian animals, they require a placenta to survive until the female stops them. Among its characteristics we find that they have the particularity of being a structure in more evolved beings. They are usually large and have a large brain, late reproduction, and long life expectancy.
Viviparous Marsupial Animals
Unlike the placentals, these viviparous animals do not have a placenta to feed themselves, so the puppy is born underdeveloped. Find warm protection with plenty of breast milk inside the marsupium (outer pouch that female marsupials have).
Viviparous marsupial animals are usually born after 38 days of gestation, then they move to the marsupium and the female becomes pregnant again several days later, leaving the embryo in a dormant state until the pouch is empty again.