Oldest remains of ancient human relative Paranthropus suggest possible tool use

Early humans may have been using complex stone tools as early as three million years ago.

Hundreds of tools used for cutting, scraping and pounding food were discovered as part of excavations in Nyayanga, a site found on the shore of Lake Victoria in Kenya. Known as Oldowan tools, these artefacts may be up to 400,000 years older than any previously known example.

Not only are these tools older than previously known, but also more widespread. While Oldowan tools eventually spread to Europe and Asia, examples from this early in time had only been found in Ethiopia, more than 1300 kilometres away.

Professor Thomas Plummer, the lead author of a study describing the finds, says, 'This is one of the oldest - if not the oldest - example of Oldowan technology anywhere in the world.'

'Our research shows this toolkit was more widely distributed at an earlier date than people realised, and that it was used to process a wide variety of plant and animal tissues.'

While the manufacture and use of Oldowan technology is generally thought to be associated with early relatives of modern humans, such as Homo habilis and Homo erectus, the discovery of two teeth from Paranthropus, another ancient human relative at the same site suggests potential use by other species.

Professor Fred Spoor, a Research Leader in human evolution at the Museum, adds, 'Not only are these Paranthropus fossils among the oldest ever found, they also hint that this ancient hominin might have used, and perhaps even made, tools to expand its diet.'

The findings of the study were published in the journal Science. 

What are Oldowan tools?

The oldest known tools, dating to around 3.3 million years ago, were unearthed in Lomekwi, northwestern Kenya, but it is not clear how long this technology lasted. 

The Oldowan tools, meanwhile, had staying power. Prior to this study, the implements were known to have been used between around 2.6 to 1.3 million years ago, becoming the first human inventions to achieve a truly global reach. 

While it's not known who first started making Oldowan tools, their period of use is long and were adopted by new species of ancient humans as they evolved. As these species spread so did the tools, which have been found in countries including Spain, Georgia, China and South Africa.

The excavations at Nyayanga further cement their place among the longest-lasting inventions in history, revealing that they were used for over 1.5 million years. 

Their persistence is likely due to the relative ease of making them, compared to more complex tools that followed. Ancient humans would have produced Oldowan tools by striking stones together, causing the rocks to fracture in certain useful ways.

Three main types of tools - hammerstones, cores and flakes - were found in Nyayanga. Hammerstones are believed to have been used to pound material, as well as produce other tools. When struck against a core, they can refine its edge to produce cutting tools, as well as break off flakes that can be used for scraping.

Dr Rick Potts, the study's senior author, says, 'With these tools, ancient hominins can crush better than an elephant's molar can and cut better than a lion's canine can.'

'For ancient humans, Oldowan technology was like suddenly evolving a brand-new set of teeth outside the body, and it opened up a new variety of foods on the African savannah to our ancestors.'

In a time before the use of fire, hammerstones could have been used to make tough plant material like starchy roots more edible by breaking it apart. The paper provides further evidence that humans were making a switch to what are known as C4 plants, a group which includes many common crops.

'Previous research has suggested that more C4 plants were being included in the diet around 2.4 million years ago, but this paper suggests it was happening even earlier,' Fred says. 'If grasses were easily available in this area, it may have been an opportunistic change that wasn't common with those living elsewhere.'

The tools could also have been used to tenderise meat, with thousands of hippopotamus bones found during excavations. Some of these bones show evidence of being cut, while a cluster of bones at one dig site is associated with a selection of tools that have been worn down through use. 

While it can't be confirmed if these ancient hominins were hunting the animals or simply scavenging the carcasses left behind by other predatory animals, it suggests there was at least some meat in their diet. 

Did other hominins use tools?

The archaeological digs at the site also uncovered two teeth from an ancient human relative known as Paranthropus. Both Homo and Paranthropus are thought to have descended from a group of hominins known as Australopithecus, from which they evolved at least three million years ago. 

The three species of Paranthropus are informally referred to as robust australopiths as a result of their large jaws and faces, inspiring the nickname 'Nutcracker man'.

'Paranthropus is not a direct ancestor of humanity, but a specialised side branch,' Fred explains. 'From the first fossil, found in South Africa, it was immediately clear that its large cheek bones, head crest and lower jaw provided ample space for very large chewing muscles to attach.'

'These features are even more pronounced in two species subsequently discovered in east Africa.'

With teeth much larger than those of a modern human, researchers have historically suggested that the species did not use tools, relying instead on its jaws to grind down large amounts of weakly nutritious food. But the work of researchers such as Jane Goodall, who found that modern primates still use tools, began to change that.

'Traditionally, Oldowan technology is associated with Homo habilis, the earliest member of our genus,' Fred says. 'Paranthropus was around at the same time, but was historically never considered to have made or used tools, as tool use was considered to be a purely human trait.'

'As more sites containing Oldowan tools and Paranthropus fossils are discovered, it becomes more possible that these hominins may have made use of them. Of course, it's also possible that the reason their fossils are found alongside tools is because Homo habilis could have been eating them.'

Further discoveries in Africa could help to clarify Paranthropus' lifestyle, and provide a greater understanding of how these ancient hominins lived.