They are 18 to 20 feet high and 50 feet long. Colouration is green to greenish brown with paler green underparts and lime-green spots on the wings of older wyverns. In flight their call is similar to a crow, while they roar when attacking. They eat any large African mammals. Many people recall it mostly eating elephants. The nomadic wyvern sometimes makes nests on crags. The wyvern egg is very large with a thick bumpy shell which changes colour to match its surroundings. The chicks are brown and lose their spines as they get older.