Nearly 5,000 cave drawings were discovered in northeastern Mexico in 2006. This month, Mexico's National Institute of Anthropology and History archeologists released their findings into the paintings.
The ages of the cave paintings remain uncertain for now because archaeologists have not found any objects in the area that could help date them, archeologists say.
Drawings of what appear to be teepees, local plants and animals like deer, lizards and centipedes can tell researchers about how the populations lived.
At least three nomadic hunter-gatherer groups -- the Guajolotes, Iconoplos and Pintos -- are believed to have made the 4,926 drawings.