biology Biology is the scientific study of life. It is a natural science with a broad scope but has several unifying themes that tie it together as a single, coherent field. For instance, all organisms are made up of cells that process hereditary i ...

, weapons are traits that are used by

males Male (symbol: ♂) is the sex of an organism that produces the gamete (sex cell) known as sperm, which fuses with the larger female gamete, or ovum, in the process of fertilization. A male organism cannot reproduce sexually without access to ...

to fight one another off for access to

mates Mates is an English surname, and may refer to: * Mates (born 1964), British newsreader and journalist * Michael Mates (born 1934), British politician * Frederick S. Mates, founded the Mates Investment Fund in 1967 that crashed in the bear market o ...

. A mate is won in battle either by a male chasing off a fellow competitor or killing it off, usually leaving the victor as the only option for the female to

reproduce Reproduction (or procreation or breeding) is the biological process by which new individual organisms – "offspring" – are produced from their "parent" or parents. Reproduction is a fundamental feature of all known life; each individual org ...

with. However, because stronger organisms, whether mentally or physically, are usually favored in combat, this also leads to the

evolution Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...

of stronger organisms in species that use combat as a way to secure mates, via

intrasexual selection Sexual selection is a mode of natural selection in which members of one biological sex choose mates of the other sex to mate with (intersexual selection), and compete with members of the same sex for access to members of the opposite sex (in ...

."Charles Darwin & Evolution." Charles Darwin & Evolution. Apr. 2014. . Examples of weapons include:

antler Antlers are extensions of an animal's skull found in members of the Cervidae (deer) family. Antlers are a single structure composed of bone, cartilage, fibrous tissue, skin, nerves, and blood vessels. They are generally found only on male ...

horns Horns or The Horns may refer to: * Plural of Horn (instrument), a group of musical instruments all with a horn-shaped bells * The Horns (Colorado), a summit on Cheyenne Mountain * ''Horns'' (novel), a dark fantasy novel written in 2010 by Joe Hill ...

, and

ossicone Ossicones are columnar or conical skin-covered bone structures on the heads of giraffes, male okapi, and some of their extinct relatives. Ossicones are distinguished from the superficially similar structures of horns and antlers by their unique ...

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References

Mating Weapons Sexual selection {{Animal anatomy-stub