Prehistoric artists used their hands to mold and model images out of wet clay. The artists would have to find a dry area, away from any dripping water and carry small amounts of water with them to soften the natural clay. These areas were typically far into the caves and hard to reach. The bison and cow at Tuc d'Audoubert, Ariege are two examples of art modeled with the hands. Details in the hair and and tail were mostly likely made from a hard rock such as chert.
For engraving in mediums harder than clay, such as limestone, artists used chert, a hard rock found all over the world. Chert is a type of microcrystalline sedimentary rock that breaks in conchoidal fractures, causing sharp edges. Chert tools have been found in Australia near Mount Gambier that were used for engravings in limestone. Chert was also mined in Indiana and used in cave art radiometrically dated to the Terminal Archaic Period. Dark-colored varieties of chert are sometimes called flint.
Sharp picks for engraving or sculptural images were made from animal bones. Bones typically found on digs came from the same animals depicted on the walls of the caves. These included bison, deer, horses, bovines, ibex and mammoths. In addition to their uses for carving, bone fragments were sometimes forced into the cave walls near other paintings. The purpose of this is unknown; it may have been a way for artists to sign their work. Bone fragments in the walls have been found in numerous Paleolithic cave art sites in France that belong to periods sometimes far apart. This means the same gestures were repeated for thousands of years.
Small flat stones have been found with engravings on them, such as the one of a bison found at Laugerie Basse. Some theorize that they may have been used as a preparatory sketch for a painting in one of the caves. The bison image is drawn with its hooves facing downward, indicating it may have been sketched from life after the bison was killed rather than in a natural position found in most cave paintings.