The ridge is usually about 2 inches (51 mm) in width at its widest point. It is believed to originate from the dog used by the original African dog population which had a similar ridge. The first depiction of a ridgeback is a wall painting describing the life of the Boers, housed in South Africa in the Voortrekker Monument.Male ridgebacks usually stand 25–27 in (64–69 cm) at the withers and weigh about 45 kg (99 lb) (FCI standard); females are typically 24–26 inches (61–66 cm) tall and about 35 kg (77 lb) in weight.