The story of human evolution is a complicated one DonSmith/Alamy

In recent weeks, we have explored the brain of a species called Homo naledi, speculated on the idea that Neanderthals might have made it to North America deep in prehistory, and found signs of Denisovan DNA in layers of dirt in a Siberian cave that don’t actually contain any fossil bones.

But who were these ancient humans? And what about the other species that pop up in the news on a regular basis? Here is New Scientist’s primer to help you understand a little bit more about seven of the most important human species in our evolutionary tree.

Homo habilis (“handy” man)

Discovered: 1960, officially named in 1964.

When and where did it live? Evolved in Africa sometime before 2 million years ago, went extinct in Africa by about 1.5 million years ago.

Significance: By the middle of the 20th century, researchers were beginning to accept that humans evolved in Africa from an ancient group of “ape people” called the australopiths. In 1960, a research team at Olduvai Gorge in Tanzania found fossil remains of a species that seemed to fall in the gap between the australopiths and humans. They named it Homo habilis – identifying it as the first true human species to evolve.


From the fragmentary fossils found, H. habilis seemed to have had a brain substantially larger than an australopith and more like that of later human species. What’s more, according to its discoverers, H. habilis behaved in a human-like way too. They suggested it produced stone tools, while the australopiths apparently did not. This feature was so important it even explains the name they chose for the species – H. habilis translates roughly as “handy man”.

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In the decades since its discovery, though, H. habilis has become a controversial species. Some researchers think it was actually an australopith, given that it doesn’t seem to have been adapted to long-distant walking, which is arguably a defining human feature. Its tool-making skills are seen as less significant too, because it is now clear that australopiths also produced stone tools.

One population of H. habilis might have evolved into the earliest indisputable human species – H. erectus.

Homo erectus (“upright man”)

Discovered: 1891, officially named the following year.

When and where did it live? Probably evolved in Africa about 2 million years ago, quickly expanded and spread across Eurasia. The date of its extinction is debated – recent estimates suggest it may have disappeared by 143,000 years ago.

Significance: It might be less well known than other extinct humans like the Neanderthals, but Homo erectus was an immensely important species. Unlike H. habilis, there is no doubting that H. erectus looked and behaved in a human-like way. It used its long legs to stride out of Africa and spread across Eurasia, making it the earliest human species known to have migrated long distances.

It was probably also the earliest human to learn how to control fire. It may have been the first to cook food too – an innovation some people think may have helped H. erectus and its descendants improve the nutritional quality of their diet, opening the way for the evolution of larger, energy-demanding brains that fuelled the emergence of even more sophisticated behaviour.

Homo neanderthalensis (the Neanderthal)

Discovered: 1829, not officially named until 1865.

When and where did it live? Appeared in Eurasia roughly 200,000 years ago and went extinct there about 40,000 years ago.

Significance: Neanderthals are the most famous of all extinct human species, probably a consequence of the fact they were the first ancient human species to be discovered by scientists, almost 200 years ago – several decades before Darwin put forward his theory of evolution by natural selection.

Neanderthals are also the best known of extinct human species: researchers have now found bones from hundreds of Neanderthals in countries across Europe, the western Asia and central Asia.

Homo neanderthalensis is sometimes labelled the “cousin” of our species, Homo sapiens. Both species seem to have shared the same “parent” species – an early human that some researchers call Homo heidelbergensis, which, in turn, was probably a descendant of H. erectus.

Exactly when the line leading to H. sapiens split from the one leading to the Neanderthals is still being debated. Some recent research suggests the split happened more than a million years ago, with a Eurasian branch eventually evolving into the Neanderthals (and the Denisovans) while an African branch evolved into H. sapiens.

Neanderthals made sophisticated stone and bone tools. Researchers have known for years that the Neanderthals could control fire, perhaps taking advantage of fires triggered by lightning. Recent evidence suggests that they may also have used knowledge of the chemical properties of minerals in their environment to start their own fires. Neanderthals also self-medicated and made art. Such findings suggest that the Neanderthals were more cognitively advanced than popularly believed.

The Denisovans

Discovered: 2010.

When and where did they live? Still unclear, but possibly throughout eastern Asia between about 200,000 years ago and 50,000 years ago.

Significance: The Denisovans are perhaps most important for the way they were discovered. All other extinct humans are what researchers call “morphospecies”: we know they were distinct species because their skeletons look different from ours, and from the skeletons of other extinct human species. The Denisovans are different. We know almost nothing about their skeletons, their appearance, or how they behaved.

In fact, the Denisovans were “discovered” in a genetics lab. With advances in genetic sequencing, researchers can now extract and sequence human DNA from bones that are hundreds of thousands of years old. In 2010, researchers analysed DNA samples pulled from fragments of 50,000-year-old human teeth and bone found in a cave in Siberia.

Given their age and where they were found, the assumption was the DNA would match known Neanderthal sequences. It didn’t – it belonged to a population of humans that, according to the most recent estimates, had last shared an ancestor with Neanderthals perhaps 765,000 years ago.

This population is now known as the Denisovans. Partly because we know so little about them, there is some reluctance to give them a full scientific name yet. If more fossils are found – and some researchers suspect such fossils have already been discovered – the Denisovans might be formally recognised as a species or subspecies – “Homo denisova”.

Homo floresiensis (the “hobbit”)

Discovered: 2003, officially named the following year.

When and where did they live? Known to have lived on the Indonesian island of Flores between about 100,000 and 50,000 years ago – an ancestral form of the species might have been present on the island at least 700,000 years ago.

Significance: Homo floresiensis was, and continues to be, an evolutionary puzzle. It had a strange mix of features – a short body, unusually long feet, and a surprisingly tiny brain.

Those are features that wouldn’t look out of place in an early species of human wandering around Africa about 2 million years ago, when humans first evolved from australopiths (see H. habilis, above). But H. floresiensis lived thousands of kilometres east of Africa, was alive just 50,000 years ago, and seems to have behaved like an advanced human in terms of its ability to control fire and cook food.

There is still no clear consensus on how H. floresiensis fits into the human evolutionary tree. Some researchers think it is a strange variant of H. erectus that became stranded on the island of Flores and evolved rapidly into a short, small-brained species. Others think there is a direct evolutionary link between H. floresiensis and H. habilis. According to this idea, a population of H. habilis left Africa about 2 million years ago and began an epic journey eastwards, ultimately settling on Flores. However, aside from the Hobbit bones themselves, there is no fossil evidence to support this idea.

Homo naledi (“star man”)

Discovered: 2013, officially named in 2015.

When and where did they live: South Africa. No officially published data on the species’ age, but unofficial reports suggest it was alive between 300,000 and 200,000 years ago.

Significance: A decade after scientists discovered H. floresiensis, another equally remarkable species was added to the human family tree. Homo naledi had a strange mix of features, with some parts of its skeleton indistinguishable from those of living people while other parts looked almost ape-like. It also had a brain little bigger than that of a chimpanzee, but seems to have been capable of sophisticated, modern human-like behaviour – most notably there is some evidence that the species deliberately disposed of its dead in a rock chamber.

Because its skeleton shows such a strange mixture of modern and ancient features it is still not clear where H. naledi belongs in the human evolutionary tree. One study published last year suggests it might sit on a branch very near the bottom, perhaps somewhere between H. habilis and H. erectus.

As such, many people anticipated that H. naledi lived at roughly the same time as H. habilis, and probably went extinct more than a million years ago as more advanced humans like H. erectus outcompeted it.

But unconfirmed reports suggest H. naledi was actually alive just a few hundred thousand years ago. If that age is confirmed, we have a new mystery to explore: how could a human that looked so primitive survive until so recently? H. floresiensis managed to do so too, of course, but probably only because it lived on an isolated island without competition from other human species.

Homo sapiens (“wise man”, or “modern humans”)

Named by scientists: 1758.

When and where did they live: The species first appeared in Africa about 200,000 years ago – began to move out of Africa at least 100,000 years ago and spread across the rest of the world.

Significance: The importance of our modern human species is obvious. For all the ingenuity of earlier human species, none seems to have been able to compete with the technological and artistic sophistication of our species.

At a physical level, our species might not have looked very different from ancient human species like the Neanderthals – the two species even interbred. But the emotional and intellectual differences might go a long way to explain why all other ancient human species that survived to see modern humans went extinct within a few thousand years of first contact. By about 40,000 years ago, ours was the last human species surviving on Earth.