In The Nature of Paleolithic Art, Dale Guthrie overturns many of the standard interpretations of the ancient cave paintings of the Paleolithic era. Among other things, Guthrie argues that many of the cave paintings were done by children and have similarities with present-day graffiti. Here is an illustration and short excerpt from the book:

Missing Fingers in Art: Ritual, Disease, Frostbite, or Kids Playing?
“Many hand images in the French Gargas-Tibran cave complex and Cosquer and in Maltravieso Cave in Spain appear to have missing fingers or other malformations. These “disfigured” hands have fueled discussions for the last 100 years. Groenen (1987) has provided a review of this debate. The central issue, of course, is that virtually all apparent mutilations are also replicable by simply contorting fingers in the stenciled hand (as one does in shadow art). But many people still insist that these represent real ritual amputations.
“More recent speculation on possible causes of these disfigured hands has focused on Raynaud’s disease, in which capillaries fail to respond normally by flushing with warm blood when hands or feet get cold. I find this explanation unconvincing, because Raynaud’s disease is seldom expressed in young men (Larson 1996), and the hands with the “missing fingers” are mainly those of young males. Individuals who experience extreme winter temperatures, like cross-country dog-mushers, winter mountain climbers, and so on, do sometimes suffer frozen tissue. Yet, in Alaska, certainly among the coldest well-populated places on earth, complete loss of individual fingers due to freezing is rare. I have never seen one case. Nor have I seen any in my travels in northern Siberia. This is despite the fact that many residents in both places have had multiple experiences of frostbite.
“These Paleolithic images will, no doubt, continue to puzzle and prompt speculation. Having played with making spatter stencils of my own hands, I find the ease with which one can replicate the “maimed-hand look” has left me very convinced that all, or virtually all, were done in fun, especially when we recall that these are largely young people’s hands and appreciate the quick, almost careless, casualness with which they were made. This phenomenon of altering the hand stencil patterns by finger contortion is also well documented from a number of other cultures.”
The preface to the book is also available on our website.