David Attenborough in The Telegraph:
Animals were the first things that human beings drew. Not plants. Not landscapes. Not even themselves. But animals. Why? The earliest known drawings are some 30,000 years old. They survive in the depths of caves in western Europe. The fact that some people crawled for half a mile or more along underground passages through the blackness is evidence enough that the production of such pictures was an act of great importance to these artists.
But what was their purpose? Maybe drawing was an essential part of the ceremonials they believed were necessary to ensure success in hunting. Maybe the paintings were intended not to bring about the death of the creatures portrayed but, on the contrary, to ensure their continued fertility so that the people would have a permanent source of meat. We cannot tell. One thing, however, is certain. These drawings are amazingly assured, wonderfully accurate and often breathtakingly beautiful.
This practice of painting images of animals on walls has persisted throughout our history. Five thousand years ago, when men in Egypt began to build the world’s first cities, they too inscribed images of animals on their walls.