Between two million years ago and relatively recent
times, the genus Homo erectus spread throughout the world, developed more
sophisticated tools, utilized fire, and evolved an anatomy more similar
to modern humans.
DATES: 1.8 million years ago to as late as10 to 27 thousand years ago
(have been dated with K/Ar, Ar/Ar, U series, ESR, and faunal dating methods)
SITES: Kenya, Tanzania, Algeria, Morocco, Georgia, the Middle East, China,
Indonesia, and Java
The cranial capacities range from 750 to 1225 cc; early forms average
900 cc; later forms average 1100 cc. The depth and robusticity of the
zygomatic bone differs from modern humans. H. erectus is similar to H.
habilis in its protruding jaws, large molars, lack of a prominent chin,
thick brow, and the long, low skull. H. erectus had human limb proportions
and human body shape (it was the first hominid to have this). Its skeleton
more robust than modern humans, suggesting considerable strength (Rightmire,
1981; Brown, 1985; Leakey, 1973; Walker, 1981; Day, 1971; Clark, 1976;
Leakey, 1976; Wolpoff, 1984. There was some sexual dimorphism in the skeleton
and one specimen shows signs of hypervitaminosis A (Walker, 1982).
The assemblages of tools found with Homo erectus are more sophisticated
than earlier tools and 2 sites are associated with fire. In Asia, Homo
erectus coexisted with Gigantopithecus. In Africa, Homo erectus coexisted
with Australopithecus (Leakey, 1971, Gowlett, 1981; Wanpo, 1995; Leakey,
1976b; Jacob, 1978; Weiner, 1998; Tianyuan, 1992).
Homo erectus is considered to be the first hominid to travel out of Africa
(although a find from China and others in Central Asia may belong to H.
habilis rather than H. erectus). Homo erectus is known from Asia (Java,
China, Pakistan, and Georgia) as of 1.7 million years ago and the Middle
East as of 1.5 million years ago (Gabunia, 1995; Klein, 1973; Larick,
1996; Howells, 1980)
Homo erectus is known in Java as early as 1.8 million years ago and as
late as 50,000 years ago. The combination of very thick crania and evidence
of healed skull fractures and head trauma have caused some to propose
that male Homo erectus fought with each other using clubs (Boaz, 2004).
The last Homo erectus populations existed in Java between 27 and 53 thousand
years ago dates which overlap with the existence of Homo sapiens sapiens
in the region (Gibbons, 1996; Thorne, 1972; Swisher, 1996). The earliest
African forms of Homo erectus have smaller and more projecting noses.
Some researchers classify these specimens as Homo ergaster and feel that
Homo ergaster or some pre-erectus population migrated from Africa before
H. erectus proper evolved. One find of Homo from 1 million years ago from
Afar (near the Red Sea) is similar to H. ergaster but also has characteristics
of Homo sapiens. Some anthropologists feel some skeletal characteristics
(the frontal keel, torus mandibularis, os epactale, and incisor shape)
of Asian erectus populations indicate that there was interbreeding between
these populations and later H. sapiens emigrants from Africa. The transitional
nature of the fossil material makes it difficult to assert which populations
should be regarded as separate species. (Dean, 1995; Lewin, 1989; Wolpoff,
1984; Turner, 1989; Gibbons, 1998; Abatte, 1998).