ABSTRACT
From a biological point of view, humans are a peculiar species of mammal. They walk on two legs, they practise a high degree of omnivory, their body is devoid of hair or other skin cover, and they have extremely large brains. Humans are also intensely social; they rely on complex behaviour for their survival, including communication by means of symbolic language. Humans have an extraordinarily long juvenile period in which behaviours and experiences are transmitted to offspring by an extensive institutionalized learning process. There is a high degree of phenotypic and genetic variation among humans; the human species is differentiated into a great number of peoples and cultures. The fact that interbreeding between populations is always possible demonstrates, however, that Homo sapiens as a whole is clearly one biological species.
