Even those few African sites that are legally protected are endangered, largely because the host countries cannot afford to enforce the laws or provide the necessary safeguards. Sun, wind, rain, termite trails and wasp nests are inexorably fading and eroding the thin layers of pigment. Population growth, urban sprawl and the lure of tourism are taking an even more rapid toll. One of the greatest threats is vandalism by visitors ignorant of the art's significance and value. Their cattle rub against the pigments and lick the rocks to get at the salt they contain.
Tourists are a particular problem.
Amateur photographers have been known to throw water and cola drinks and even to urinate on the art to enhance its contrast and make the colors more vivid. The touristic appetite for souvenirs is especially destructive. I've never seen such vandalism. Roving bands of armed guerrillas have contributed to the destruction, using rock art for target practice and destroying precious images. At a little-known site in the foothills of Kenya's Mount Elgon, unknown visitors scratched their initials into the surface of an early Iron Age frieze.