Homo erectus: The First Human Species to Leave Africa

Homo erectus, the “upright man”, is an extinct human species that lived from around 1.9 million years ago until roughly 110,000 years ago. It was the first hominin with a body much like ours, the first known to spread far beyond Africa, reaching western Asia, China and Java, and the maker of the Acheulean hand axe, one of the longest-used tools in history. With a span of more than 1.5 million years, it was one of the most successful human species that ever lived.

Discovery: from Java Man to a global species

The story began not in Africa but in Indonesia. In 1891 and 1892 the Dutch doctor Eugène Dubois, searching for a “missing link” between apes and humans, found a skullcap, a thighbone and teeth at Trinil on the Solo River in Java. In 1894 he named them Pithecanthropus erectus, “upright ape-man”. The find, known as Java Man, was hotly disputed for decades.

In the 1920s and 1930s excavations at Zhoukoudian near Beijing produced many more fossils. The Canadian anatomist Davidson Black named them Sinanthropus pekinensis in 1927, and the first skullcap was found in 1929 by the Chinese archaeologist Pei Wenzhong. The German anatomist Franz Weidenreich made detailed casts and descriptions, which became vital after the original Peking Man fossils were lost in 1941 during the Second World War.

Scientists gradually realised that the Java and China fossils were closely related. In 1950 the biologist Ernst Mayr argued that they should be grouped in a single species within our own genus, Homo erectus. Later finds in Africa, especially at Olduvai Gorge in Tanzania and around Lake Turkana in Kenya, showed that the species was also present, and older, in Africa.

Origins in Africa

Homo erectus appears in the fossil record a little before 1.9 million years ago. One of the oldest skulls, KNM-ER 3733 from Koobi Fora in Kenya, dates to about 1.6 to 1.8 million years ago. A skullcap from Drimolen in South Africa, published in 2020, has been dated to about 2.04 to 1.95 million years ago and may be the oldest known member of the species.

Its ancestry is uncertain. Homo erectus may have evolved from a population of early Homo such as Homo habilis, but the two species lived side by side in East Africa for several hundred thousand years, so a simple line of descent is unlikely. Some scientists call the early African fossils Homo ergaster, “working man”, and reserve Homo erectus for Asia; others see one variable species.

A human-like body

The best evidence for the body of Homo erectus is Turkana Boy, an almost complete skeleton about 1.5 million years old found in Kenya in 1984. It shows long legs, short arms, a narrow pelvis and a body built for walking and possibly running long distances in open country. Adults may have stood around 1.45 to 1.85 metres tall, a range that overlaps with modern humans.

The skull was long and low, with a thick bony brow ridge, a sloping forehead and a ridge called a keel running along the top. There was no true chin. Brain size varied widely, from about 550 cubic centimetres in some early specimens to around 1,250 in later Asian ones, with an average of roughly 900 cubic centimetres.

These changes in body and brain suggest a shift in diet and behaviour. Smaller teeth and a larger body point to more energy-rich food, probably including meat and marrow obtained by hunting or scavenging, along with tubers and other plants. Some researchers have argued that cooking played a role, but this remains debated.

Tools: the Acheulean hand axe

Early Homo erectus used simple Oldowan flakes and cores. From about 1.76 million years ago at Kokiselei in West Turkana, Kenya, a new technology appears: the Acheulean hand axe, a large, symmetrical tool shaped on both faces. Hand axes and cleavers were used for cutting, butchery and woodworking.

The Acheulean tradition lasted for well over a million years and spread across Africa, western Asia and Europe. It is less common in East Asia, a contrast once known as the Movius Line, although hand axes have since been found in parts of China. Making a good hand axe required planning and skill, and some researchers think teaching or imitation was needed to pass on the technique.

There is also debated evidence that Homo erectus used fire. Burned bone and plant ash at Wonderwerk Cave in South Africa, dated to about 1 million years ago, lie in layers with Acheulean tools. Earlier traces of burning in Kenya are more contested.

Spreading across Asia and late survival

Homo erectus, or hominins closely related to it, had reached the southern Caucasus by about 1.8 million years ago. The skulls from Dmanisi in Georgia, dated to about 1.77 million years, are the oldest hominin fossils known outside Africa. Remarkably, they were small-brained and used simple Oldowan-type tools, which suggests that hominins left Africa before hand axes were invented.

Stone tools from Shangchen in central China, published in 2018, have been dated to about 2.1 million years ago, which hints at an even earlier movement, though no fossils were found with them. In Java, fossils from Sangiran and other sites date back to around 1.5 million years or more. In China, Homo erectus is known from Lantian, Zhoukoudian and other sites, with dates ranging from more than 1 million to a few hundred thousand years ago.

Homo erectus survived longest in Southeast Asia. At Ngandong on the Solo River, Dutch excavations in the 1930s recovered a dozen skullcaps and two leg bones. Their age was long uncertain, but a 2020 study in Nature dated the bone bed to between about 117,000 and 108,000 years ago.

By then Homo sapiens was already present in Africa, and Neanderthals and Denisovans lived in Eurasia. The Ngandong people were probably the last of a long-isolated population. Their extinction may have been linked to changes in climate and vegetation, as open woodland gave way to rainforest on Java.

Ancestor of later humans?

What happened to Homo erectus in Africa and western Eurasia is closely tied to the origins of later humans. From around 700,000 to 600,000 years ago, fossils in Africa and Europe show larger brains and less heavily built skulls. Many researchers group these under the name Homo heidelbergensis, while others prefer to split them into several regional species.

On this view, African populations of Homo erectus, or a close relative, gave rise to the common ancestors of Homo sapiens, Neanderthals and Denisovans. Ancient DNA suggests that these three groups shared an ancestor roughly 500,000 to 800,000 years ago. Asian Homo erectus, by contrast, appears to have followed its own path and died out.

Scientists also debate how much variation one species can contain. The small-brained Dmanisi skulls, the robust skulls of Java and the larger-brained fossils of China differ markedly. Some researchers see them as regional forms of a single, long-lived species; others think several species have been lumped together under one name. New fossils and more precise dating, rather than any single discovery, are slowly shaping the picture.

Myths and facts

Myth: Homo erectus was the first human ancestor to walk upright. Upright walking is much older. Australopiths such as Lucy walked on two legs more than three million years ago. Homo erectus was, however, the first with fully modern body proportions.

Myth: Homo erectus was a single, uniform population. The fossils vary greatly in size and shape across time and place, and scientists still debate whether they represent one species or several.

Fact: it was not the direct ancestor of every later human. Asian Homo erectus populations probably left no descendants. Later humans are thought to descend from African populations of Homo erectus or a close relative.

By the numbers

Timeline

• c. 2 million years ago: Earliest probable Homo erectus, such as the Drimolen skullcap in South Africa.
• c. 1.77 million years ago: Hominins live at Dmanisi in Georgia.
• c. 1.76 million years ago: Earliest known Acheulean hand axes at Kokiselei, Kenya.
• c. 1.5 million years ago: Turkana Boy dies near Lake Turkana, Kenya.
• c. 1 million years ago: Traces of fire use at Wonderwerk Cave, South Africa.
• c. 117,000 to 108,000 years ago: Last known Homo erectus at Ngandong, Java.
• 1891-1892: Eugène Dubois finds the Trinil fossils in Java.
• 1950: Ernst Mayr groups the Java and China fossils as Homo erectus.

Why it matters

Homo erectus marks the point at which human ancestors began to look and live much like us: tall, long-legged, toolmaking and able to colonise new lands. Its spread from Africa across Asia set a pattern that later humans, including our own species, would follow, and its long survival shows how adaptable the human lineage had become.