page_title: Biological ornament
section_title: Examples
hierarchical_section_title: Biological ornament / Examples
caption_attribution_description: Deutsch: Blausteinsee Tierwelt: Rotauge (Rutilus rutilus). English: Common roach (Rutilus rutilus) photograped in Blausteinsee, an artificial lake north of Eschweiler in North Rhine-Westphalia, Germany. Svenska: Mört (Rutilus rutilus) fotograferad i den konstgjorda sjön Blausteinsee i det tyska förbundslandet Nordrhein-Westfalen. Equipment and post-processing&#58; Camera: Canon Digital IXUS 500 (5 megapixels) Chassis: Canon WP-DC 800 (for IXUS 400–500) Flash: built-in Recording mode: JPG, 5 megapixels, fine resolution, low compression Possibly post-processed with Adobe Photoshop (Elements 2.0) to improve contrast and white balance
context_page_description: A biological ornament is a characteristic of an animal that appears to serve a decorative function rather than a utilitarian function. Many are secondary sexual characteristics, and others appear on young birds during the period when they are dependent on being fed by their parents. Ornaments are used in displays to attract mates, which may lead to the evolutionary process known as sexual selection. An animal may shake, lengthen, or spread out its ornament in order to get the attention of the opposite sex, which will in turn choose the most attractive one with which to mate. Ornaments are most often observed in males and choosing an extravagantly ornamented male benefits females because the genes that produce the ornament will be passed on to her offspring, increasing their own reproductive fitness. As Ronald Fisher noted, the male offspring will inherit the ornament while the female offspring will inherit the preference for said ornament, which can lead to a positive feedback loop known as a Fisherian runaway. These structures serve as cues to animal sexual behaviour, that is, they are sensory signals that affect mating responses.
context_section_description: Ornamentation is a common biological trait seen in birds. The male quetzal has elaborate ornamentation to aid in mating. Male quetzals have iridescent green wing coverts, back, chest and head, and a red belly. During mating season, male quetzals grow twin tail feathers that form an amazing train up to three feet long (one meter) with vibrant colors. Most female quetzals have no ornamentation and are drab.  Coloration and tail feather length in quetzals help determine mate choice because the females choose the more elaborately ornamented males.
  Other birds that exhibit ornamentation include sage grouses and widowbirds. Sage grouse birds gather in a lek, or a special display area, and strut and display their plumage to attract a mate. Whereas, the extraordinary tail feathers of the male long-tailed widowbird are displayed to choosy females while the male flies above his grassland territory.
  Biological ornamentation is also seen in the common roach fish, Rutilus rutilus. Male roach develop sexual ornaments (breeding tubercles) during the breeding season. Roach display lek-like spawning behavior, whereby females choose between males, usually choosing the more elaborately ornamented ones.
caption: The male lekking fish, Rutilus, displays elaborate colors in its scales
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