Early humans adapted to harsh conditions more than a million years ago

A long-standing question about when archaic members of the genus Homo adapted to harsh environments such as deserts and rainforests has been answered in a new research paper.

The study, published in Nature Communications Earth and Environment, finds it was earlier than originally thought.

“We reveal how early humans — known as hominins — were able to thrive under harsh conditions,” says lead author Dr. Julio Mercader, PhD, a professor in both the Faculty of Arts and the Faculty of Science at the University of Calgary.

The multidisciplinary analysis by researchers at UCalgary, the University of Manitoba and 17 other institutions around the world shows Homo erectus adapted at least 1.2 million years ago — long before our species, Homo sapiens, emerged.

Mercader, who studies human evolution, explains that the archaeological research was done at Olduvai Gorge, a UNESCO World Heritage site in Tanzania.

“By doing archeology, what we can see is that Homo erectus keeps coming back to the same place in the landscape over thousands of years,” he says in an interview. “It’s not a one-time camp. 

“There is thickness to the accumulation of archeological remains and fossils that is telling us that a species was targeting a very specific point in the landscape to do what they came here to do.”

For example, the archeological data shows that groups of Homo erectus repeatedly returned to live in locations with freshwater availability such as ponds and developed specialized stone tools.

Co-author Dr. Jed Kaplan, PhD, a Canada Research Chair in global systems modelling in the Faculty of Science, says he was able to reconstruct past landscapes to simulate the East African region at the time.

“Things like extreme climate change leading to desertification would have been really difficult for hominins to survive,” he says. 

“What we discovered in the study is that, in fact, we find plenty of evidence for hominin activity under environmental conditions — so climate, vegetation — that suggest really hot and dry periods.

“So, it’s changing our understanding of the adaptability of these early hominins to extreme environments and demonstrating that Homo erectus were more adaptable than we realized.”

Kaplan, a professor in the Department of Earth, Energy and Environment, says it has interesting implications.

“It’s well known that by the time modern humans come on the landscape, 200,000 to 300,000 years ago, we are really adaptable,” he explains. “We not only spread out in Africa but also start inhabiting all of these really different environments — everything from the Arctic tundra to the Sahara dessert and the tropical rainforest and everything in between.”

It’s now become clear, he says, that our human ancestors were demonstrating their ability to survive in a wide range of environments — including really extreme ones.

“That’s new, that pretty neat,” Kaplan says.

Ultimately, he expects scientists will be able to show the overall adaptability of Homo erectus.

“These prominent ancestors were not just able to survive in every kind of environment from rainforest to dessert, but also build boats and get across ocean straits and get to different islands.”

It’s still unknown whether they could talk or had language, he says, but they may have been able to communicate in other ways to find resources such as water or rocks for making tools or fire.

Kaplan says the study is important because it helps us to learn about who we are and where we come from.

“It is a contribution to a better understanding of our planet and humans’ role in it,” he says.

Both researchers note that the paper is also important because it brought together a broad range of experts – from archaeologists and biogeochemists to paleoclimate specialists – to produce some ground-breaking research.

“It illustrates how modern climate research works,” says Mercader. “It is a model for addressing the science of past and present-day climate science research.”