The Hohokam created a variety of rock art known today as petroglyphs and pictographs. Petroglyphs are images pecked into the rock by hammerstones and are the most common type of rock art produced by the Hohokam. Pictographs, on the other hand, are painted images on rock surfaces. Because pictographs are painted, they tend not to last as long as petroglyphs and may wear away from exposure to sun, wind, rain, and other elements, which may account for the low number of Hohokam pictographs that have been found.
All of the mountain ranges surrounding the Salt River Valley contain Hohokam petroglyphs, especially the South Mountains, located 4 miles (6.5 km) south of Pueblo Grande. Hohokam petroglyphs also occur in the McDowell Mountains, the Superstition Mountains, the White Tank Mountains, and in the Phoenix Mountains.
The Hohokam used a variety of images and designs in their rock art, both geometric and representational, many of which also appear on their red-on-buff pottery. Geometric designs include circles, spirals, crosses, meandering lines and other elements. Representational images include animals, birds, snakes and humans. Many of the petroglyphs of humans show them performing certain activities such as dancing, flute playing or hunting. Geometric and representational images are often found mingled together and may represent scenes of some kind. Some humans hold objects in their hands and are wearing headdresses.
For many years archaeologists have debated and proposed theories on the meaning and use of rock art. Hohokam rock art may have been mnemonic devices (meaning assisting memories) used to record events, similar to Pima calendar sticks. Some rock art may be clan or totemic symbols, trail markers, boundary markers or territorial signals. Many archaeologists today think that rock art had some kind of ceremonial or religious significance. Petroglyphs and pictographs may have marked sacred locations, and possibly were created as part of priestly or shamanistic rituals such as curing ceremonies or vision quests. Some of the humans, birds, and animals depicted in Hohokam rock art have prominent roles in Pima mythology.
Although no one can be certain what Hohokam rock art truly meant to its creators, archaeologists have concluded that it was not simply a form of graffiti. Rock art took a considerable amount of time and energy to produce, and some panels of rock art are in practically inaccessible areas high on cliff walls or in caves. This would suggest that the rock art left by the Hohokam was something more than just a means of keeping hands busy, but had a special significance for them.
There is much yet to learn about Hohokam rock art and further study is likely to shed new insights into this fascinating subject. That is why rock art sites must be protected against vandalism and the encroachment of urban development.
The construction of platform mounds, ballcourts and big houses, as well as the creation of imaginative pottery designs and rock art images, suggest that the Hohokam had an elaborate belief system. Mythological stories may have been depicted in some of the rock art and pottery designs. The cycles of nature probably played an important role in the Hohokam belief systems, as they did in Mesoamerica. Archaeologists have determined that the Hohokam had knowledge of astronomy and made observations of the movements of the sun, the moon and possibly other celestial phenomena. That knowledge probably was important for regulating ceremonial cycles throughout the year.