The chronology of Saudi Arabian rock art remains largely tentative. The earliest Phase 1, tentatively attributed to the Neolithic, are distinctive in having large-sized human and animal figures depicted in low or bas-relief with detailed realistic physical features, except the faces, which are usually obscure and ambiguous. The art of the later Neolithic period represents highly skilled and artistic images of human and animals. In Phase II a change occurred in the art style with no more large-sized human and animal figures, with realistic physical features being produced. Instead, the figures became comparatively smaller and schematized. The typical funnel-shaped faces of bovids of phase 1 were replaced by triangular or conical shaped faces, while the horns remained exaggeratedly large and highly stylized. In Phase III, large compositions of human and animal figures, associated with a variety of animal species and non-representational and geometric motifs became common. The figures became schematic, mostly outlined, and, for the first time, stick or linear, and simplified human and animal figures appeared in rock art compositions. Foot and hand prints were seen for the first time along with a variety of animal species, such as presumed camels, ibex, deer, lions, dogs, wolves, and gazelles, becoming common. Phase IV is represented by a period preceding the introduction of writing or the literary period in Arabia. Highly schematic, abstract, stick-like linear human and animal figures, along with geometric and non-representational motifs, were depicted as signs and symbols. With the change in Arabian climate and environmental conditions, from cool and humid in the Neolithic to the extremely hot and dry in the Bronze Age, the camel became the main animal of rock assemblages.
