The genus Smaug contains the largest species of the cordylidae. All members of this group are robustly built and well armored, possessing distinctively enlarged occipital spines and sharply keeled caudal scales. The largest of all cordylids, Smaug giganteus, are commonly known as “Sungazers”, because of their distinctive habit of basking with their head pointed skywards. Unusually for cordylids, Smaug giganteus is entirely terricolous, living in deep, self-excavated burrows, which it retreats into when threatened. The other members of the genus prefer deep, horizontal crevices in shaded rock outcrops. The genus was named after the antagonistic dragon from J. R. R. Tolkein’s The Hobbit. According to Tolkien, (who was born in the Free State where these animals occur) the name Smaug is "the past tense of the primitive Germanic verb smeugan, meaning "to squeeze through a hole", making it a doubly appropriate name for dragon-like lizards that live in burrows or rock cracks.

Because of their preference for rocky habitat, most members of the genus are not considered to be in any danger from habitat destruction. However, range fragmentation as a result of increased arable farming, collection for the pet trade and muti (traditional african medicine) is having a significant impact on Smaug giganteus populations.