The viviparous are those animals where the fetal process of the offspring evolves inside the mother , specifically in the placenta, where the embryo develops thanks to food, so that at birth, its organs and skeleton are complete.
In general, mammals are classified in this category, not counting monotremes that are oviparous, in addition to plesiosaurs, ichthyosaurs and mosasaurs that reproduced because their eggs were not able to survive in the sea.
Marsupials fall into this category but in a different way, since they do develop inside the mother but since they do not have a placenta, they are born prematurely and continue their evolution in the marsupial sac .
Viviparous animals are sexual in nature, when performing intercourse, the man’s sperm remains within the female’s reproductive system, so that fertilization and the production of an embryo take place.
Germination is variable depending on the species , but it has a direct link with the size of the animal, due to the period that some need to develop compared to others of smaller size.
The number of offspring that they can have in a birth can change between one species of animal and another , for example, the rabbit can have twelve offspring, the dog and the cat seven offspring, and the giraffe one or two offspring, and so on. with the long list of viviparous animals.
Examples of viviparous animals
Most mammals are viviparous, except monotremes such as the platypus or the echidna, which are oviparous. Marine animals are also placed in this category as is the most special flying mammal, the bat.
The most common are domestic animals such as rabbits, cats or dogs, as well as farm animals such as cows, pigs, sheep or horses, and wild animals such as tigers, monkeys or elephants. Also those animals that live in more extreme places such as the desert (camels) or the poles (polar bear).
Examples of viviparous amphibians
Viviparous amphibians are not very common but there are some other exceptions, the urodel amphibians such as the salamander or the newt, and also some species of caecilian , an amphibian with an elongated, ringed body, without limbs and without scales.
Examples of viviparous reptiles
There are only some species of reptiles that are viviparous, as is the case of water snakes, lizards, the occasional European viper or rattlesnakes, marine snakes or boas, among others.
These species feed the offspring with elements of maternal blood and keep them in the reproductive part.
Examples of viviparous fish
Today not many viviparous fish have been revealed, but there are some, such as the mollinesias, a species of black fish from tropical aquariums and the guppies or million . These fish are certainly oviviparous, that is, fish that have their eggs inside the mother’s body, the young are born alive and after birth they are independent, without the need for paternal or maternal care.