 There are differences between knuckle-walking in chimpanzees and gorillas : juvenile chimpanzees engage in less knuckle-walking than juvenile gorillas.
<clarity>  There are differences between knuckle-walking in chimpanzees and gorillas : juvenile chimpanzees engage in less knuckle-walking than juvenile gorillas.
 Differences exist between knuckle-walking in chimpanzees and gorillas : juvenile chimpanzees engage in less knuckle-walking than juvenile gorillas.