He simply wanted to show that we are not the only species to take pleasure in creating visual effects, and thus that the aesthetic sense probably has far older roots than many of us assume. The main dividing line between ape and human art is representation. In spite of isolated claims of apes' producing recognizable images, human art seems to be unique in its ability to depict the reality that surrounds us. Yet, even if substantial differences between human and ape art remain, they should not distract us from the undeniable common ground. The human artist imagines and strives for an end product.
Human art is a conscious act of creation.
It is in that regard that ape art, rather than insulting the human ego, provides a glimpse of the wellspring of our species' universal artistic impulse. Frans B.M. de Waal is a professor of psychology and director of the Living Links Center at Emory University. He writes regularly for The Chronicle.