Primates can be defined as the most developed order of mammals. All Primates are classified into one taxonomic order, which divides into two major suborders that differentiate physically from each other after taking different evolutionary lines. The lower primates prosimii commonly called prosimians, meaning "pre-monkey", was the first suborder to evolve and includes animals such as lemurs, lorises, etc.
Anthropoidea was the subsequent suborder to evolve, 90% of anthropoidea is made up by the many different species of monkeys, and the remaining 10% are apes and humans. This suborder is divided into two infraorders, the Platyrrhini also known as the new world monkeys since these are only found in the Americas, and the catarrhini which includes apes, humans and old world monkeys, those found in Africa, Asia and some parts of Europe. There are distinguishable differences between the two infraorders, such as the absence of the pre-hensile tail in old world monkeys, and differences in nose shape and teeth structure, which relates to the differences in diet and olfactory capabilities.
The anthropoids are much larger, have highly developed stereoscopic vision, prehensile hands, show a higher level of intelligence, exceptional cognitive capabilities and have versatile diets which makes them very adaptable to changing environments, these characteristics have made them the most successful animals to populate earth.
Primates have a very important characteristic in that they have a large brain size to body ratio compared to any other taxonomic group, this therefore is one of the reasons primate behaviour is so complex and can explain partially the amazing cognitive abilities shown by non-human primates.
Brain tissue is extremely expensive to maintain, so the large brain primates have developed should represent an important evolutionary advantage that has been carried and constantly developed through evolution. In order to...