Viviparous: development of the embryo in the mother's womb
What they are - biological definition
Viviparous are animals whose embryo develops within the womb. Thus all placental mammals (eutherians) are viviparous animals.
This type of animal reproduction is known as viviparity.
Summary of main features:
- In viviparous animals the nutrition of the embryo (and after the fetus) is performed in the maternal placenta.
- In many species of viviparous animals, the transport of nutrients and water present in the maternal blood is performed through the umbilical cord.
- When pregnancy occurs normally, the puppy is born as soon as its development is complete.
- The gestation period of the viviparous varies according to each species. In the case of humans, it lasts nine months.
Examples of viviparous animals
Difference between viviparous and oviparous
While in viviparous the embryo develops within the mother's womb, in oviparous animals it develops within an egg.
- Monotreme animals (example: platypus) are mammals but not viviparous. These animals are oviparous, meaning embryo development occurs within an egg.
“We don't find live animals only among mammals. The chameleon snake is a reptile, but it is viviparous. The salamander is an amphibian and is also viviparous. Besides these we can mention the emperor scorpion which is also viviparous, although it is an arachnid.
Rhino and pig: two other examples of viviparous animals.