Until recently, most classifications
included only humans in this family; other apes were put in the family Pongidae (from
which the gibbons were sometimes separated as the Hylobatidae). The evidence linking
humans to gorillas and chimps has grown dramatically in the past two decades, especially
with the increased use of molecular techniques. It now appears that chimps, gorillas, and
humans form a clade of closely related species; orangutans are slightly less close
phylogenetically, and gibbons are a more distant branch. Here we follow a classification
reflecting those relationships. Chimps, gorillas, humans, and orangutans make up the
family Hominidae; gibbons are separated as the closely related Hylobatidae.
Thus
constituted, the Hominidae includes 4 genera and 5 species. Its nonhuman members are
restricted to equatorial Africa, Sumatra and Borneo. Hominid fossils date to the Miocene
and are known from Africa and Asia.
Hominids range in weight from 48 kg to 270 kg. Males are larger than females. They are
the largest primates, with robust bodies and well-developed forearms. Their pollex
and hallux
are opposable except in humans, who have lost opposability of the big toe. All digits have
flattened nails. No hominid has a tail, and none has ischial callosities. Numerous
skeletal differences between hominids and other primates are related to their upright or
semi-upright stance.
All members of this family have large braincase. Most have a prominent face and
prognathous jaw; again, humans are exceptional. All are catarrhine, with nostrils close
together and facing forward and downward. The dental
formula is the same for all members of the group: 2/2, 1/1, 2/2, 3/3 = 32. Hominids
have broad incisors and their canines
are never developed into tusks. The upper molars
are quadrate
and bunodont;
the lowers are bunodont and possess a hypoconulid.
The uppers lack lophs connecting labial and lingual cusps and thus, in contrast to
cercopithecids, are not bilophodont.
Hominids are omnivorous, primarily frugivorous or folivorous. All but humans are good
climbers, but only the orangutan is really arboreal.
Members of this family are well-known for the complexity of their social behavior.
Facial expression and complex vocalizations play an important role in the behavior of
hominids. All make and use nests.
Species included in database:
- Gorilla gorilla beringei [Mountain Gorilla] -t-
- Gorilla gorilla gorilla [Western Lowland Gorilla] -pts-
- Homo sapiens -s-
- Pan paniscus [Bonobo or Pygmy Chimpanzee] -t-
- Pan troglodytes [Chimpanzee] -pts-
- Pongo pygmaeus [Orangutan] -pt-
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