Anthropologists study humans in a similar fashion that entomologists study insects or herpetologists study reptiles. However, anthropology limits its focus to a single living species, Homo sapiens.

How as Homo sapiens do humans fit in the overall biological scheme? Human identity is narrowed down to approximately 200 living species, including monkeys, apes, humans, and some other less familiar animals. A comparison that identifies a species involves 4 categories of comparison: place in nature, evolution, reproduction, and variation. Using these categories, humans can be considered primates—a bipedal primate, a sexual primate, and a cultural primate.

Taxonomy reflects evolutionary relationships. The degree of similarity and difference between two organisms is a direct result of the amount of time they have been separated, evolutionarily. The Linnean (phonetic) taxonomy is faulted. Evolution may occur within different lines at different rates as demonstrated by the fossil record, and genetic comparisons of living species allow us to reconstruct a ‘branching’ order. Branching points (nodes) of evolutionary ‘trees’ graphically represent this.

Cladistics offers one approach to taxonomy. It is a model suggesting that all African apes are part of the family hominidae, and thus, hominids. Humans and our direct ancestors are called hominins. The Prosimii and Anthropoidea make up the two primate suborders. The Anthropoidea are further subdivided into Platyrrhini who inhabit the New World and the Catarrhini in the Old World. Humans are Old World primates.

Primates comprise about 200 species, and exhibit a great deal of anatomical and behavioral diversity. Using seven categories, we can generalize and identify the range of variation with the primates: the brain (large and complex relative to body size); vision (the predominant primate sense—primates all exhibit depth perception as a result of stereoscopic vision); the face (primates have a reduced sense of smell and thus a reduced face: some variation exists); hands and feet (primates exhibit grasping ability with an opposable thumb; some variation exists; they also have nails instead of claws); limbs (arms and legs are characteristically flexible and able to twist and turn; all primates can briefly walk bipedally); reproduction (most primate species give birth to one offspring at a time; there is a long period of infant dependency); and behavioral patterns (primates are social animals and recognize individuals). Individual differences distinguish humans from other primates based upon these categories

Using the taxonomic system created by Linnaeus in the eighteenth century for classifying living organisms, we may see humans as animals, vertebrates, mammals, and, most important, as primates. Primates may be generally defined as large-brained, tree-dwelling mammals with three-dimensional vision and grasping hands who produce few offspring at a time but take extended and direct care of those offspring, preparing them to live in groups.

Like each of the existing 200 primate species, the human primate exhibits its own unique version of the primate theme. Humans have extremely large brains with the ability to create cultures with complex symbolic communication systems, are completely terrestrial, and, unlike all other primates, are habitually bipedal. We also display some differences in our sexual behaviors that are connected to these other characteristics.