What are Ovoviviparous Animals?
What Does Ovoviviparous Animals Mean
We explain what ovoviviparous animals are, their characteristics and examples. Also, oviparous and viviparous animiales.
What are ovoviviparous animals?
In biology , ovoviviparous animals are those whose reproduction mechanism consists of the formation of eggs inside the female's womb , where the embryo matures until it is close to hatching, and only then are they deposited or expelled from the body of the parent .
Thus, ovoviviparity is somehow halfway between the oviparous and viviparous mode of reproduction , that is , it is something intermediate between ordinary egg laying and parturition . This is because animals of this type develop inside an egg, but said egg does not leave the mother's body until a few moments before hatching.
This type of reproductive mechanism is common among invertebrate species , but also among some species of reptiles and fish. But in all cases an internal fertilization occurs, that is, during copulation the male introduces his genetic material into the female's body.
Depending on the relationship established between the mother's body and the egg where the embryo develops, we can classify ovoviviparous animals into:
- Those whose embryos are fed throughout the gestation process from the yolk of the egg, without requiring any type of maternal food .
- Those whose embryos deplete the energy content of the egg and require a supply of nutrients from the maternal body, in the form of unfertilized eggs or uterine secretions.
It can help you: Reproduction of fish
Characteristics of ovoviviparous animals
Ovoviviparous animals are characterized as follows:
- Its reproductive mechanism involves internal fertilization and subsequent retention of the egg in a specialized duct within its reproductive tract. This amounts to saying that, instead of laying their eggs and then hatching them, as birds do, these animals hatch them inside their bodies and release them when the young are about to hatch.
- This process is very similar in appearance to that of viviparous ones, which give birth to the young alive and formed, but unlike them, ovoviviparous ones do not form a placenta, since the nutrition of the young generally depends on the contents of the egg. In other words, there is no placenta and an umbilical cord that connects the mother with the baby .
- The eggs of the ovoviviparous are much larger and with a thinner shell than those of the oviparous ones , which allows in some species that, when expelled from the maternal body, the egg cracks and the young go free into the environment.
Examples of ovoviviparous animals
Some examples of ovoviviparous animals are the following:
- Different species of sharks , such as Squalus acanthias (known as galludo, spiny dogfish or hornbill), reproduce ovoviviparously: fertilized eggs hatch early within the female's oviduct, and the young feed on its contents and secretions from the maternal body until they are completely expelled and formed.
- Certain vipers and snakes , such as the asp ( Vipera aspis ), typical of Europe, reproduce in an ovoviviparous way, expelling the live young along with the remains of the hatched egg from the mother's body, when they are already mature.
- Most of the species of marine rays (rajiformes or rayiformes) expel the young from the mother's body once the egg is about to hatch, so that they give the appearance of "giving birth". In other species, the eggs are expelled early and adhere to plants and rocks by means of a sticky substance.
- The amphibian species Limnonectes larvaepartus , a type of frog endemic to Indonesia, is one of the few examples of ovoviviparous amphibians , whose fertilization is internal and, once hatched, the tadpoles are expelled directly into the water by the mother's body.
Oviparous animals are those that reproduce by laying eggs . They are the most numerous animals on the planet, and can reproduce by internal fertilization (the male fertilizes the female directly), or external (male and female release their gametes and fertilization occurs in the environment).
In both cases, once fertilization has been carried out and the egg is placed, the parents have nothing to do with the nutrition of the embryo, which depends on the contents of the egg itself.
Most insects, fish, amphibians, birds, and various invertebrates belong to this classification.
More in: Oviparous animals
Viviparous animals are those that gestate their young within a placenta, inside the mother's body , where they are protected and fed until the moment of their birth and liberation in the outside world. The maternal body provides them with the necessary nutrients for their development, so they require internal fertilization and no eggs are produced at any time.
The mammals in general are viviparous, including humans and higher primates.
More in: Viviparous animals