Viviparous animals are those characterized by development of the embryo inside the womb. For ex. rabbit , dog , horse .
Living beings such as these also have the particularity to reproduce sexually. This means that the female is fertilized by the male once it deposits its sperm inside its belly, and in this way the so-called embryo begins to develop.
The viviparous are then differentiated from the oviparous , which are animals that reproduce from an egg, which is formed in an external environment. An example of these animals are hens or pigeons.
The ovoviviparous , in turn, differ from the previous ones. The latter are the animals whose breeding are born from an egg, but this egg remains inside the female organism until the brood is fully developed. An animal that reproduces in this way is the viper, as well as some fish and other reptiles .
The gestation in viviparous
The period of gestation of the viviparous varies according to the species and this depends, among other things, on the size of the animal. That is, the period of an elephant will be significantly longer than that of a mouse, to give just one example.
Another issue that varies according to the animal is the number of offspring a female can conceive each time she becomes pregnant. For example, a rabbit has many more offspring than the human being.
In most cases, the breeding of viviparous animals develops in the placenta. It is there where the baby manages to obtain the nutrients and oxygen that are necessary to stay alive and develop their organs, until the moment they are born.
Anyway, within the viviparous we can identify a small group of animals, such as kangaroos or koalas, which are called marsupials and which differ from the rest precisely because they do not have placenta. But the breeding, which is born very underdeveloped, ends up forming as such in the so-called “marsupial bag”.
Examples of viviparous animals
- Rabbit : your pregnancy time is, in general, less than 30 days.
- Giraffe : it’s gestation period lasts about 15 months.
- Elephant : these mammals have pregnancies that last between 21 and 22 months.
- Cat : the gestation time of these animals is between 60 and 70 days, approximately.
- Mouse : an animal like this does not spend more than 20 days in the womb.
- Bat: the pregnancy period of this animal is between 3 and 6 months, depending on the cases.
- Dog: 9 weeks is what lasts, approximately, the pregnancy of these animals.
- Whale: the pregnancy of an animal like this can last up to a year.
- Bear : the pregnancy of this wild animal can last up to 8 months.
- Pig : the gestation period of this farm animal is around 110 days.
- Horse: these animals have a pregnancy that lasts about 11 or 12 months.
- Cow : before giving birth, this ruminant is about 280 days pregnant.
- Sheep : a sheep must be about five months pregnant before giving birth to its young.
- Koala : the pregnancy itself of these marsupials lasts about a month. Although it must be taken into account that the breeding is not fully developed, but continues to form in the marsupial bag.
- Chimpanzee : these animals have a gestation period that lasts a little less than 9 months.
- Dolphin : these mammals have a gestation period that is around 11 months.
- Kangaroo : in this type of marsupials, pregnancy lasts about 40 days. As in the case of the koala, the development of the offspring is prolonged outside the maternal womb, in the marsupial pouch.
- Chinchilla: the gestation period of these rodents is approximately 110 days.
- Donkey : the pregnancy of these animals lasts approximately 12 months.
- Rhinoceros: the pregnancy of these animals is one of the longest, since it can last up to a year and a half.