Most animals use sexual reproduction, in which mating occurs between a male and a female. Various mating behaviors have evolved across different species.

In some species, the males compete with each other for the chance to mate with females. In other species, the females compete in order to attract the male mate.

Some animals, like these swans, are monogamous, meaning they mate with a single partner for life. Others. like the sea lion, are polygamous, meaning they have several partners.

Polygamy characterizes the majority of animal mating behaviors.

One type of polygamy is called polygyny, in which one male mates with several females. For example, a male sea lion may have up to 80 females in his harem.

A rarer type of polygamy is called polyandry, in which one female mates with several males. Among mammals, the only species that practices polyandry is the naked mole rat.

Many animals use color, sound, smell, and even light to attract a mate. Others perform complicated dance routines or build special displays. These activities are known as courtship behaviors.

The male bowerbird builds a small chamber that he decorates with bright objects such as berries, shells, flowers, and feathers. He then dances at the entrance to attract a female mate into his bower.

Fireflies produce flashes of light via a chemical reaction that takes place in their tails. The males flash at night to attract females. Their flashes can be seen over 500 meters away.

Courtship behavior may play a signaling role. For instance, like the firefly, a signaler may simply be saying, “Here I am, come and mate with me.”

In more complex examples, a series of fixed action patterns may be used by both partners to initiate mating. In stickleback fish, the Dutch biologist Niko Tinbergen found that the red belly of the male attracts the female. The female responds using a head-up posture to initiate courtship. The male then uses zigzag motions to lead the female to the nest, where she deposits her eggs for fertilization.

In a third variation, a sequence of behaviors by one partner may be some kind of test that the other sex uses to gauge the suitability of the signaler as a partner. Deer, which are animals that practice polygyny, use this type of courtship behavior. Males in the herd fight to establish dominance, and only the strongest male mates with the females. The strongest male may be the fittest to reproduce.

In some species, like these ruffed grouse, males group together into a lek, for the pupose of display to attract females. Females visit the lek, choose a male based on his appearance, mate with the male, and then leave. In the lek, the males maximize their reproductive success when they arrange themselves to highlight the contrast of their plumage.

Social behaviors are often beneficial to a group of animals, but there can also be disadvantages to living in groups. Next we’ll explore the costs and benefits associated with group behaviors.

Copyright 2006 The Regents of the University of California and Monterey Institute for Technology and Education