An incredible new finding has blown the lid off a secret that the famous pre-human “Lucy” had been hiding: she could climb trees, and in fact probably lived in the trees. Scientists beleive Lucy, who died 3.2 million years ago, met her end falling from a tree, but they found out much more than that by examining her body in more detail.

Bone scans showed Lucy had thicker, stronger upper arms compared to her thighs, as is the case with chimpanees. Lucy was clearly an upright walker on the ground, but she could quickly scale a tree and hang from its branches like a monkey, according to a statement from the University of Texas at Austin.

Scientists came to this determination by looking at CT scans of her upper arm and thigh bones. Heavily used muscles tend to pull on the attached bones, forcing the bones to become strong and thicker. In people, gymnasts tend to have stronger arm bones than most people, for example.

“It may seem unique from our perspective that early hominins like Lucy combined walking on the ground on two legs with a significant amount of tree climbing, but Lucy didn’t know she was unique,” said UT Austin paleoanthropologist John Kappelman. “It is a well-established fact that the skeleton responds to loads during life, adding bone to resist high forces and subtracting bone when forces are reduced. Tennis players are a nice example: Studies have shown that the cortical bone in the shaft of the racquet arm is more heavily built up than that in the non-racquet arm.”