page_title: Primate
section_title: Sexual dimorphism
hierarchical_section_title: Primate / Anatomy and physiology / Sexual dimorphism
caption_attribution_description: English: Silverback Mountain Gorilla with one of his females
context_page_description: A primate is a eutherian mammal constituting the taxonomic order Primates. Primates arose 85–55 million years ago first from small terrestrial mammals, which adapted to living in the trees of tropical forests: many primate characteristics represent adaptations to life in this challenging environment, including large brains, visual acuity, color vision, altered shoulder girdle, and dextrous hands. Primates range in size from Madame Berthe's mouse lemur, which weighs 30 g, to the eastern gorilla, weighing over 200 kg. There are 190–448 species of living primates, depending on which classification is used. New primate species continue to be discovered: over 25 species were described in the first decade of the 2000s, and eleven since 2010.
  Primates are divided into two distinct suborders. The first suborder is called strepsirrhines, which contains lemurs, galagos, and lorisids. These primates can be found throughout Africa, Madagascar, India, and Southeast Asia. The colloquial names of species ending in -nosed refer to the rhinarium of the primate. The second suborder is called haplorhines, which contains "dry-nosed" primates in the tarsier, monkey, and ape clades.
context_section_description: Sexual dimorphism is often exhibited in simians, though to a greater degree in Old World species (apes and some monkeys) than New World species. Recent studies involve comparing DNA to examine both the variation in the expression of the dimorphism among primates and the fundamental causes of sexual dimorphism. Primates usually have dimorphism in body mass and canine tooth size along with pelage and skin color. The dimorphism can be attributed to and affected by different factors, including mating system, size, habitat and diet.
  Comparative analyses have generated a more complete understanding of the relationship between sexual selection, natural selection, and mating systems in primates. Studies have shown that dimorphism is the product of changes in both male and female traits. Ontogenetic scaling, where relative extension of a common growth trajectory occurs, may give some insight into the relationship between sexual dimorphism and growth patterns. Some evidence from the fossil record suggests that there was convergent evolution of dimorphism, and some extinct hominids probably had greater dimorphism than any living primate.
caption: Distinct sexual size dimorphism can be seen between the male and female mountain gorilla
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