Kappelman shrugs off the controversy, noting he is a trained geologist, and that study co-author Lawrence Todd has worked extensively on the bones of bison driven off cliffs by prehistoric hunters.
“Between Larry and me, we have 80 years of experience of looking at bones,” says Kappelman. “We know what broken bones look like. We’re not clinicians, but this subset of fractures cannot be explained by geological processes. We looked at being trampled by, say, an elephant. But nothing we looked at explained these injuries.”
Harvard University evolutionary biologist Daniel Lieberman, who was not involved in the study, called it a “creative analysis” and saw the team’s conclusions as reasonable.
“The fact is that Lucy has all kinds of adaptations both for walking upright and for being arboreal,” says Lieberman. “The findings tell us one thing: She spent time in trees. In eastern Africa, if you want to sleep somewhere at night, and you don’t have fire and you don’t have weapons, you’d probably want to climb a tree to stay safe.”