Researchers have just published a set of papers describing one of our closest early human ancestors, which was discovered deep inside a cave in South Africa. According to a report from the BBC, the most recent research reveals that Homo naledi’s hands and feet likely allowed it to spend equal time living on the ground and in the trees.

Naledi’s feet suggest that it walked on flat land, but its hands had strong curved fingers that likely allowed it to grasp tree branches and travel above ground as well. Despite their ability to shift effortlessly between environments, naledi had another trick on hand.

The bone structure of the early hominid’s hands is extremely similar to that of modern humans and our extinct close relatives, Homo neanderthalis. The key to modern humans’ dexterity lies in the structure of our hands. The bones and muscles in our hands allow us to grasp, twist, pry, and squeeze objects with ease.

One of the most important evolutionary developments, the thumb, allows us to manipulate objects in a way that no other animal can. This development led to the introduction of tools in human society.

Homo naledi’s hands indicate that the early hominid likely had at least some of the capability to make tools. In addition to the fingers and the thumbs, naledi also had a complex wrist joint that likely allowed it a wide range of movement. Researchers even believe that the invention of tools could have pushed the evolution of the hand in a direction that allowed for even greater and more precise uses.

Researchers don’t quite know what type of tools the early hominid likely made and used, but they have little doubt that they used tools based on the shape of the hand. There were no tools uncovered next to the ancient remains inside the Rising Star Cave in the Cradle of Humankind World Heritage Site, located right outside of Johannesburg, South Africa.

The discovery of the complex hand in the absence of tools raises a number of fascinating questions. It was likely that naledi had a brain in similar size and function to a modern chimp. So could it have had the mental capacity to make and use tools? So far, scientists have only excavated a small portion of the cave. They hope to discover more evidence about the early hominid, which may allow them to determine what it used its advanced dexterity for.

Researchers have uncovered the remains of about 15 naledi individuals so far. Among the remains, they found roughly 150 bones from the species’ hands, with a nearly complete adult right hand. The researchers, from Wits University, took extra care to make sure that the position of the bones on the ground was documented before they collected them.

According to head researcher Dr. Kivell, “The near-perfect articulation means that when the individual was put there or died there, the bones were not subsequently disturbed or moved. There can’t have been water flowing through this cave, for example, because those little bones of the wrist and the fingertips would be the first to disappear.”

Researchers also uncovered 107-foot bones at Rising Star, including a nearly complete right adult foot. Naledi’s feet were also strikingly similar to those of modern humans. This leads researchers to believe that they could walk with little problem.

The feet weren’t identical to human’s feet, however. They had a different curvature in the toe bones, or phalanges, and they also had a lower arch. Naledi was probably very comfortable walking on the ground, but it likely spent time in the trees hiding from predators and foraging.

Researchers still don’t know when Homo naledi existed. Preliminary estimates placed the species as living roughly 2 million years ago, but similarities with the Indonesian species Homo floresiensis may mean that naledi could have lived as recently as 12,000 years ago.

Whether naledi proves to be old or young in the scope of human evolution, the discovery is a huge win for archaeologists and anthropologists seeking to complete the hominid family tree no matter what. If it had existed 2 million years ago, the finding would speak to the stunning evolutionary diversity within the Homo genus. If it proves to be more closely related to floresiensis, it would suggest stunning migratory patterns that demonstrate the massive range of early hominids.