This rather large species of water monitor (Varanus niloticus) is also known as a leguaan in South Africa.
Monitor lizards are, as a rule, almost entirely carnivorous, consuming prey as varied as insects, crustaceans, arachnids, myriapods, molluscs, fish, amphibians, reptiles, birds, and mammals. Most species feed on invertebrates as juveniles and shift to feeding on vertebrates as adults.
Water monitors are excellent swimmers, folding their legs in and using their tails like crocodiles, and can stay underwater for well over half an hour. They can run astonishingly fast over a short distance and invariably head for water when disturbed.
A Water Monitor making his way across the road into the longer grass on Sibuya Game Reserve.
These lizards can grow up to 2.5 meters long and this fellow looks pretty close to that.