Life was no picnic for our ancestors 1.8 million years ago

Reconstructing an early East African landscape where human ancestors lived 1.8 million years ago, researchers have found that life was quite tough in the ancient times.

Our human ancestors, who looked like a cross between apes and modern humans, had access to food, water and shady shelter at a site in Olduvai Gorge, Tanzania. They even had lots of stone tools with sharp edges, said Gail Ashley, professor at Rutgers University in New Jersey.

But "it was tough living," she said.

"It was a very stressful life because they were in continual competition with carnivores for their food," Ashley noted.

Competing carnivores included lions, leopards and hyenas, according to Ashley.

The study was published in the Proceedings of the National Academy of Sciences.

Famous British paleoanthropologist Mary Leakey discovered the site in 1959 and uncovered thousands of animal bones and stone tools.

Through exhaustive excavations in the last decade, Ashley, other scientists and students collected numerous soil samples and studied them via carbon isotope analysis.

The landscape, it turned out, had a freshwater spring, wetlands and woodland as well as grasslands.

"We were able to map out what the plants were on the landscape with respect to where the humans and their stone tools were found," Ashley said.

"That's never been done before. Mapping was done by analysing the soils in one geological bed, and in that bed there were bones of two different hominin species," she said.

The two species of hominins, or early humans, are Paranthropus boisei - robust and pretty small-brained - and Homo habilis, a lighter-boned species.

Homo habilis had a bigger brain and was more in sync with our human evolutionary tree, according to Ashley.

Both species were about 4.5 to 5.5 feet tall, and their lifespan was likely about 30 to 40 years.

Through their research, the scientists learned that the shady woodland had palm and acacia trees.

But the researchers believe that the hominins did not camp there. The primates probably obtained carcasses elsewhere and ate the meat in the woods for safety, Ashley said.

Hominins likely used the site for a long time, perhaps tens or hundreds of years, Ashley said.