Our ancient human relatives had jaws like nutcrackers that allowed the hominids to chomp down on hard nuts and seeds and adapt to changes in food sources in their environment, a new computer simulation reveals. Today's humans have comparatively small faces and teeth, making us ill-equipped to bite down forcefully on hard objects. Apparently that wasn't the case for Australopithecus africanus , which lived 3.3 million to 2.5 million years ago. An international team of researchers used computed tomography scanning to digitally recreate an A. africanus skull to see how the jaw operated and what forces it could produce. Then,...