Text and pictures from : "Field guide to snakes and other reptiles of southern Africa" - by Bill Branch
These are the most characteristic lizards of southern Africa. The body is stocky, and the limps are always well developed. The head is triangular and falttened on top, and covered with large shields that are fused to the skull. The eyes and eyelids are well developed. The eardrums are visible, but are partly shielded by scales. The body scales have osteoderms and are overlapping usually keeled, and sometimes spiny. They are arranged in regular rows (girdles), sometimes seperated by granular interspaces. The tail which has whorls of spiny scales, can be shed and regenarated, albeit slowly and poorly.
They are diurnal and mainly rockliving (some species live on the ground or in trees). The thick scales with their bony plates protect them from abraison against rough rock. To evade predators, many species jam themselves into rock cracks by inflating the body and shortening and thickening the skull, which has an unusual hinged structure. They eat a wide variety of large invertebrates, while some of the bigger species also eat small vertebrates and plant matter. All are viviparous, giving birth to a few ( 1-6) largre bebies each year. Some lives in diffuse colonies, but they only rerely are territorial or have obvious social hierachies. This is reflected in the drab colour of the adult males, who do, nonethless, have active femoral pores. Sexual maturity is reached in 2 - 4 years, and they are long-lived( up to 25 years is known in captivity).
Their greatest diversity and probable origin is south of the Zambezi River, although a number of species extend into central and E. Africa ( Cordylus rivae reaches Ethiopia).The taxonomy of some species is confused, particularly regarding the races of C.warreni and C.cordylus. Twenty species are recognized at present, with 19 in the region( many with local races), 17 of which are endemic. Endangered species, see SARDB.