Primate Anatomy : Primate Primates

1600 Words Mar 16th, 2015 7 Pages
Primate Brains
The primate order to which we as humans belong can be divided into two sub-orders: the Strepsirrhini, also known across much literature as prosiminans, containing lemurs and lorises and the Haplorrhini containing tarsiers, monkeys and apes. The Strepsirrhini divide further into Lemuriformes and Lorisiformes, and the Haplorrhini divide into Tarsiiformes and Simiiformes, also known as anthropoids which consist of apes and humans. The Simiiformes divide into Platyrrhini (New World monkeys) and Catarrhini (Old World monkeys and hominoids), (Napier, 2014). Fig.1 attached shows the divisions of primate classification. Primates have various characteristics that identify them from other vertebrates such as, opposable thumbs, nails instead of claws, increased juvenile growth period and relatively large brains, (Boyd & Silk, 2011)
Primates are well known for their uncharacteristically large brains compared to their body size. They have brains about twice the size of what is expected for their body size, with humans having the largest brain of all relative to body size. (Aboitiz & Montiel, 2012). This was shown by Jerison, who not only showed that there was an increase in brain size related to body size, but also calculated the encephalisation quotient which determines how much the brain size deviates from the expected value. Jerison also states that there are differences between prosimians and antrhopoids in terms of brain size, indicating anthropoids have a brain 2-3…
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