Cool Finds

Discovery of First Fossil Hand Linked to P. Boisei Suggests the Bygone Human Relative Could Have Used Tools

A new study sheds light on the enduring mystery of whether our ancient cousins were toolmakers, too

Margherita Bassi | Daily Correspondent

October 21, 2025

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Researchers have taken a massive step toward solving a decades-long paleontological mystery—did Paranthropus boisei, an extinct human cousin, make tools?

The discovery of the first hand and foot bones clearly linked to P. boisei suggests the species would have been able to, as researchers detail in a study published October 15 in the journal Nature.

“The authors make a compelling case that this individual would have been able to grip rocks with sufficient precision to have been able to make and use simple stone tools,” David Strait, a paleoanthropologist at Washington University in St. Louis who did not participate in the research, tells National Geographic’s Tim Vernimmen. “This is arguably the best evidence yet found indicating Paranthropus was a toolmaker.”

P. boisei likely split off from our last common ancestor more than three million years ago and lived in eastern Africa around 1.2 million to 2.3 million years ago. While our distant relative is known for its powerful jaws and huge teeth, the fossil record was previously limited almost completely to the species’ teeth and skulls, making it difficult to deduce whether P. boisei could make and use stone tools. While paleontologists have found sites with both Homo and Paranthropus fossils, researchers generally attribute any associated stone tools to the former rather than the latter.

Now, however, “these authors are showing the hand morphology of Paranthropus was slightly different than what we see in the genus Homo,” Michael Petraglia, an archaeologist at Griffith University in Australia who was not involved in the research, explains to the Australian Broadcasting Corporation’s Ellen Phiddian. Despite those differences, he adds, P. boisei was “nevertheless potentially a tool user as well.”

The recently analyzed hand bones belong to a partial skeleton discovered and excavated in Kenya between 2019 and 2021. Found in sediment deposits dating to around 1.5 million years old, they reveal similarities to both modern humans and gorillas.

The fossils indicate that P. boisei’s human-like hand proportions would have allowed it to handle stone tools with dexterity equal to that of early Homo species. P. boisei lacked the highly adaptive wrist structure found in Neanderthals and later humans—but the species did boast a powerful, gorilla-like grasp.

“It is clearly the hand of [a] human ancestor but also has features that are remarkably similar to gorillas, which is surprising,” Tracy Kivell, a paleoanthropologist at the Max Planck Institute for Evolutionary Anthropology, tells CNN’s Katie Hunt. Kivell didn’t participate in the research, but she contributed to a commentary published with the study. “No other hominin that we know of has hand morphology that is so gorilla-like, which greatly broadens our perspective on what is ‘possible’ within [the] human evolutionary story of hand use,” she adds.

The fossilized foot bones are also telling, revealing that P. boisei walked upright and on two legs, lead author and Stony Brook University paleoanthropologist Carrie S. Mongle says in a statement. “The foot is unquestionably adapted to walking upright on two legs,” Mongle adds.

The research also informs our understanding of early hominins—the group including modern humans, extinct humans and our closest ancestors—according to the statement. For example, though early Homo species seem to have depended more on tools, Paranthropus’ face, teeth, jaw and hand remains suggest they probably consumed a specialized diet of plants.

The study doesn’t prove that our bygone relatives used tools. But discovering that they had the dexterity that could have allowed it has huge significance for the decades-long debate. “There has been a long controversy about whether or not this species made and used stone tools,” says Matt Tocheri, an anthropologist at Lakehead University in Canada and a study co-author, in the statement. “This fossil evidence effectively ends that debate.”

Margherita Bassi | Read More

Margherita Bassi is a freelance journalist and trilingual storyteller. Her work has appeared in publications including BBC Travel, Discover magazine, Live Science, Atlas Obscura and Hidden Compass.