Research in genetics offers a means to classify humans which is more precise than broad phenotypes (such as skin color), and does not correlate with geographic ancestry.

I'm not even sure that you could term them intelligent in the same manner that we classify humans.

Prior to the current scientific classification of humans, philosophers and scientists have made various attempts to classify humans.

Classic and medieval taxonomy grouped living things according to characteristics, and classifying humans as animals meant that they have various animal characteristics (moving, eating, breathing, etc.).

Biologists classify humans, along with only a few other species, as great apes (species in the family Hominidae).

Most anthropologists have classified humans into 3 large groups.

Very often, the term is also used for different theories of anthropology and other closely-related disciplines to create evidence, which would allow to classify humans into groups.

Some anthropologists believe that classifying humans into races invites over-simplification.

He classified humans as the white and the colored races, claiming that the whites were more civilized.

Weart's explanation for the democratic and the oligarchic peace is the human tendency to classify other humans into ingroup and outgroup, documented in many psychological studies.