Why Were They Made?
While their purpose is not known definitively, some educated guesses may be made by analogy with the culture of other indigenous groups who survived into modern times, as follows.
Some sites may have been "increase sites", where a ceremony would be held to increase the availability of a food source such as kangaroos or fish. It is thought that most of the sites depicting animals are of this type.
Another group of sites may have been where initiation ceremonies were held, to celebrate and facilitate the transition of a young boy into manhood. In other parts of Australia, we know that an initiation ceremony often involves a ceremonial path from childhood into manhood, and so the lines of steps, or mundoes, may indicate initiation sites.
Other sites show "Culture Heroes" or "Ancestral Beings" such as Baiame, who has a striped head-dress and often a striped body, and Daramulan who has a large club foot and may have been part-emu.
Some sites also show evidence of Aboriginal Astronomy.
It should also be recognised that increase sites, initiation sites, culture-hero sites, and astronomical sites are not necessarily distinct, and one site may fall into any or all of these categories.
Read more about this topic: Sydney Rock Engravings