Viviparous animals, who reproduce by giving birth to young ones, have epidermal hair on their skin and external ears.
Some animals reproduce by laying eggs and some animals by giving birth to young ones. There are some patterns in nature that gives clues to mode of reproduction, for example, some have external ears and some do not. Animals who reproduce by giving birth to young ones have epidermal hair on their skin and external ears. Animals who reproduce by giving birth to offsprings are known as vivparous animals. The animals that reproduce by laying eggs do not have epidermal hair or external ears. The animals which lay eggs are called oviparous animals.