viviparous – (of an animal) giving birth to live young

(pronounced vih-vih-puh-rus)

To remember the meaning of viviparous, use the following mnemonic:

The visitor was a vicar who was very prosperous (viviparous) and brought gifts to celebrate the live recording of the birth. 

Viviparous refers to animals that give birth to live young rather than laying eggs, with the developing offspring receiving nourishment directly from the mother's body during gestation. This reproductive strategy is most commonly seen in mammals, where the embryo develops inside the mother's uterus and receives nutrients and oxygen through the placenta and umbilical chord. Examples include humans, dogs, cats, whales, and most other mammals. 

The advantage that viviparous animals have is that their developing young are protected inside the mother's body form predators, diseases and environmental hazards, and they receive a constant supply of nutrients and optimal conditions for development.

However this reproductive method requires significant energy investment from the mother, limits the number of offspring that can be produced at one time, and makes the mother more vulnerable during pregnancy.