Nearly 5,000 cave paintings likely made by early hunter-gathers were discovered in a mountain range in northeastern Mexico near the U.S. border, surprising researchers, who report that up to now pre-Hispanic groups were not known to dwell so far north.

Images of humans, deer, lizards and centipedes, as well as skyscapes and abstract scenes are depicted in red, black, yellow and white. The paintings were spread throughout 11 sites, but about one third of the 4,926 paintings covered the walls of just one cave, which has been dubbed "The Cave of Horses."

Discovered in caves and ravines of the Sierra de San Carlos, Municipality of Burgos, Tamaulipas, the paintings were likely created by three groups of hunter-gatherers in who lived in the region known as the Guajolotes, the Iconoplos and the Pintos Some of the paintings suggest the groups hunted, fished and gathered food.

Scientists were unable to date the paintings on the spot, but may later use chemical and radiocarbon analyses to determine the art's age.

"[The find is] important because with this we were able to document the presence of pre-Hispanic groups in Burgos, where before we said there were none," said archaeologist Martha Garcia Sanchez of the Autonomous University of Zacatecas.

"These groups escaped Spanish control for almost 200 years," Garcia Sanchez said. "They fled to the San Carlos mountain range where they had water, plants and animals to eat. The Spaniards didn't go into the mountain and its valleys."

The findings were presented during the second meeting of Historic Archaeology, in Mexico's National History Museum.