New research suggests ancient ancestors to humans walked on two feet, even as toddlers, while also spending much of their lives climbing through the trees of Africa.

The new study, recently published in Science Advances, examined the skeletal foot of a toddler that lived 3.32 million years ago and determined the foot's structure was apt to walk on two feet, but also had attributes akin to climbing than adults from the same era. 

The research team looked at the foot of Selam, a young female Australopithecus afarensis, who was discovered in 2002 in Ethiopia. They found the big toe was more capable of moving side-to-side than skeletons of similar adult feet, meaning it would be better at climbing through branches and latching onto its mother.

"For the first time, we have an amazing window into what walking was like for a (2.5)-year-old, more than 3 million years ago," Jeremy DeSilva, an associate professor of anthropology at Dartmouth College, in Hanover, N.H. and lead author in the study, said in a statement.

"This is the most complete foot of an ancient juvenile ever discovered."

A 2012 study of Selam’s shoulder blade also showed the species would be effective when it comes to climbing.

DeSilva said his research also reveals the toddler would have been quite skilled at walking on two feet, based on the shape of the foot. 

"Walking on two legs is a hallmark of being human, but walking poorly in a landscape full of predators is a recipe for extinction,” DeSilva said.

The Australopithecus afarensis had both ape and human features. It had a smaller brain and an ape-like face, but could walk upright and had similar teeth to humans. The species also grew to about a third of the size of humans, which DeSilva says meant the ability to climb trees was necessary for survival.

“If you were living in Africa 3 million years ago without fire, without structures and without any means of defense, you'd better be able get up in a tree when the sun goes down," he said.

The most famous discovery of the Australopithecus afarensis came in 1974 when researchers found Lucy, a fully-grown adult female. Later, Selam was found just a few miles away from Lucy and was then given the nickname “baby Lucy,” despite being alive around 200,000 years before Lucy.