The pairwise union of individuals for sexual reproduction - ultimately resulting in the formation of zygotes.

Mating is the pairing of opposite-sex or hermaphrodite organisms. It is usually for sexual reproduction. Some definitions limit the term to pairing between animals.[1][2] Other definitions extend the term to crossing in plants and fungi. It is usual for mating in plants or fungi to be called cross-fertilization, or "crossing" if the offspring have DNA from both genetic sources.[3]

Dragonflies (Austrogomphus guerini) mating

Copulation is the union of the sex organs of two sexually reproducing animals for internal fertilization. Fertilization is the actual fusion of gametes.[4]

Mating may also lead to external fertilization. This is done by amphibians, most fish, many lower animals, and plants. Many aquatic species just spread their eggs and sperm in the water at one specific time of year. That time varies between species.

For some hermaphroditic species, copulation is not needed because the parent organism can self-fertilize (autogamy). In some flowering plants self-pollination can happen within the same flower, and some hermaphrodite animals self-fertilize. Many gastropods are hermaphrodite, and do simultaneous copulation in pairs. So do earthworms.

In some birds, mating includes behaviors such as nest-building and feeding offspring. The human practice of artificial insemination of domesticated animals is part of animal husbandry.


  1. The Free Dictionary. "Mate". Retrieved May 31, 2013.
  2. The Penguin Dictionary of Biology does not list the term.
  3. Note Darwin's titles (short form): Fertilisation of orchids, and Cross and self fertilisation.
  4. The Free Dictionary. "'Fertilization' - definition of". Farlex, Inc. Retrieved 25 January 2014.