Ian Moffat, Flinders University
If you bumped into a hom*o erectus in the street you might not recognise them as being very different from you. You’d see a certain “human-ness” in the stance, and his or her size and shape might be similar to yours.
But their face would be flatter, with a more obvious brow. And having a conversation would be hard – his or her language skills would be poor (although they could certainly craft a stone tool or light a fire).
Of course this is entirely hypothetical, as hom*o erectus is now extinct. This enigmatic human ancestor probably evolved in Africa more than 2 million years ago, although the timing of their disappearance is less clear.
hom*o erectus was in the news over 2018 thanks to new discoveries in the Philippines and China, which have transformed our understanding of this not too distant family member.
So who was hom*o erectus? And could 2019 be the year we learn more about our mysterious ancestor?
Where and when did they live?
hom*o erectus was first discovered in Java, Indonesia and then China – these are the famous “Java Man” and “Peking Man” fossils. Eugène Dubois’ 1891 discovery on Java (originally called Pithecanthropus erectus) was a key piece of evidence in supporting Darwin’s ideas of human evolution.
The recent discovery of stone artefacts in the Loess Plateau of China suggests that a hominin, probably hom*o erectus, was living in the region by 2.1 million years ago. This evidence pushes back their presence in Asia back by at least 400,000 years.
Other ancient hom*o erectus sites are present in the Caucasus region of Georgia (1.8 million years ago), on Java and in Africa.
hom*o erectus is thought to have become mostly extinct following the emergence of modern humans – yet some specimens from Java have been dated (with some controversy) to as recently as 40,000 years ago. If this dating is correct, it suggests that they coexisted with hom*o sapiens, although probably only in very small pockets in Indonesia.
The expansion of hom*o erectus throughout the globe was the first time that a hominin species had ventured beyond Africa, and occurred 2 million years before modern humans replicated this great feat of exploration. They may have been encouraged to spread so rapidly by the expansion of grassland during this period, driven by climate change. This created more habitats for plant-eating animals and so increased the amount of available prey.
What did they look like?
hom*o erectus was the first of our ancestors to physically resemble modern humans. They were taller and their brain was larger than previous hominin species such as Australopithecus sp. or hom*o habilis.
They had a slightly different face to us: it was flatter with more prominent brow ridges.
The long legs and the fact that they were fully upright meant hom*o erectus individuals were efficient walkers and could cover larger ranges than their ancestors.
Their body shape also meant that they could control their temperature and water balance well and so were well suited for living in open forests.
What did they eat?
hom*o erectus were probably advanced scavengers who augmented their diet with some predation rather than sophisticated hunters. In fact, they probably occupied a similar ecological niche to hyenas today.
The importance of meat in their diets is still contested, with some researchers considering they were primarily meat eaters and others believing that they had a much broader diet.
How smart where they?
hom*o erectus was much smarter than previous hominins, being the first species to use fire and may have been the first to live in hunter-gather groups. They made stone tools in a style called the Acheulian, characterised by distinctive hand axes.
Despite this, their cognitive ability fell a long way short of modern humans. There is currently no evidence that hom*o erectus was capable of undertaking modern behaviours such as using language or making art.
The importance of the recent discovery of archaeological material attributed to hom*o erectus in the Philippines helps us learn more details about what this species may have been capable of.
Previously, it was widely accepted that hom*o erectus was not able to undertake water crossings. This theory fitted with their presence as far as Java, but not across deeper water represented by the Wallace line to travel further east.
A discovery in the Philippines (and possibly in Sulawesi) overturns this, and opens the exciting possibility that hom*o erectus may have been more capable sailors than we previously thought.
How are they related to us?
One of the most contentious aspects of hom*o erectus is who to include in the species. While many researchers include a wide range of specimens from around the world as hom*o erectus, some classify the African and Eurasian specimens as hom*o ergaster. Others use the terms hom*o erectus senso stricto (ie. in the narrow sense) for the Asian specimens and hom*o erectus senso lato (ie. in the broad sense) for all specimens.
This somewhat confusing situation is actually far clearer than the early history of hom*o erectus where a wide range of names including Anthropopithecus, hom*o leakeyi, Pithecanthropus, Sinanthropus, Meganthropus, and Telanthropus were used. The reason for this complexity is that hom*o erectus (whatever you choose to call them) have a comparatively wide range of morphological characteristics making it difficult to decide how much diversity to include within the definition of the species.
What is clear is that hom*o erectus sits somewhere on the human lineage as an ancestor to modern humans, serving as a transition from early hominins such as Australopithecus to hom*o heidelbergensis, hom*o neanderthalensis and hom*o sapiens.
What next for hom*o erectus?
No area of archaeology has seen such vibrant change in recent years than how we understand our family tree. New species have been discovered (and debated) and the ages of the earliest examples of various species are constantly being revised. Unfortunately we only have limited fossils to work with and so new specimens and sites can quickly change our understanding of human evolution.
There is no doubt that ancient DNA studies will contribute to resolving this uncertainty – however DNA sequences have not yet been recovered from hom*o erectus. We await this eventual discovery with bated breath!
This article has been updated to correct the spelling of hom*o habilis.
Ian Moffat, ARC DECRA Research Fellow in Archaeological Science, Flinders University
This article is republished from The Conversation under a Creative Commons license. Read the original article.
