Nickname: Upright Man

Date of Discovery: 1891 by Eugene Dubois

Location of Initial Discovery: Java, Indonesia

Time Range: 1.8 mya - 100,000 ya 

Geographic Span: Africa, Asia, and Europe

With the Homo erectus spanning across Europe, Africa, and Asia, it is clear that it existed in a diverse range of environments spanning from woodlands and grasslands to very dry climates.  The Homo erectus ability to survive during Africa's shift from woodlands to hyperarid environment showcases the strength and adaptability of the species (Mercader et al. 2025). It is predicted that in Asia the landscape most likely existed of lake areas and large grasslands which allowed the Homo erectus to have a similar diet to modern humans. 

'Java Man' or Trinil 1, 2, and 3 is the type specimen of the Homo erectus. It was discovered in 1891 by Eugene Dubois in Trinil, Indonesia on the island of Java. This type specimen includes 3 fossils: a skull cap, a femur, and an isolated tooth. Dubois initially named the fossils "Pithecanthropus erectus" but the term 'Java Man' became more commonly used as it was simpler. These fossils were first believed to be an intermediate between apes and modern humans but with further scientific research, it was discovered that these were linked to the Homo erectus which is not a direct link to either modern humans or apes. The significance of these fossils were that they provided the first evidence of an upright human-like posture and showed that the Homo erectus had a much smaller brain than modern day Homo sapiens. (Rizal et al. 2020)

Homo erectus saw a gradual increase in cranial capacity as time went on, indicating that hominin evolution may not be as punctuated and is more continuous. In the Asian subsample of H. erectus, temporal increases in cranial capacity was determined, although the cause of this is not known. This gradual increase of cranial capacity is also seen in sequence with H. sapiens, where "later" specimens had larger brain size which could mean that the same selective pressures that caused a larger brain capacity in H. sapiens may also be the same seen in H. erectus (Leigh 1992).  Some studies show that the brain and the body co-evolved together, linking the selection of a larger brain correlating to the selection of a larger body (Grabowski 2016). This trend is also seen in H. erectus, as they had much larger body sizes in comparison to its ancestors as well as a larger brain size discussed earlier. One theory that supports the trend in brain growth, is the Radiator theory, where increasing bipedal traits lead to a complex cranial vein network that was better at cooling the growing, heat-sensitive brain (Falk 2011), that would allow for the more upright hominins to develop and sustain the large brains. Other selection pressures include changing climate, diet, availability of food, and genetic mutations may have lead toward the selection of a larger brain. We should also take the social environment into account as well; Early Homo, with H. erectus included, lived in groups and would engage in parental assistance and complex foraging strategies that would require intense cooperation (Porzio 2020). H. erectus is associated with Oldowan tools and Acheulean tools, including bifacial hand axes and use of prepared cores and may have been one of the first hominins to control the use of fire to cook food and keep warm. Wrangham's hypothesis explains the act of cooking meat and vegetation may have been more nutritious than eating raw food materials, which would have supported their larger brains and bodies. 

The first apparent migration of H. erectus into areas of Northern Africa, the Middle East, Georgia, and East Asia was, as specified earlier, around 1.8 mya. This migration was during a time of vegetational change in the Southern Mediterranean region, where we saw a large number of mammals also migrating due the the environmental changes (Bertoldi et al. 1989). H. erectus morphology also suggests that they were able to walk long distances and were adaptable to many different habitats which would allow for migration and travel to be less of an energy burden (Dennell 2003). There is also evidence suggesting that there was periodic migration during these times as climate fluctuated, and hunter-gathering practices followed those fluctuations where during dry times, small groups of hominins would leave areas to find more fertile areas. This indicated less of a colonization of new lands, and more of small-scale occupation of good hunting/gathering grounds. There are many hypothetical routes of which these early hominins may have taken to get out of Africa, many of which relied on the hypothesis of global glacial movements and sea levels to deem true. One route that has the most scientific backing is Sinai, which included a multitude of physical barriers to cross during the Pleistocene and would have been the only land route out of Africa (Derricourt 2006).