Do all animals mate?

Higher animals, reptiles, and mammals mate because they have two genders. Fish, however, almost always fertilize their eggs after they have been laid.

Mating is an adaptation for the perpetuation of species.

Sexual division increases the genetic variations. Plants also have sexual reproduction, but do not technically "mate".

Some animals reproduce asexually so they can produce offspring without mating. Animals such as the hydra can reproduce asexually by budding, producing a clone of itself.