This huge predatory lizard is the descendant of modern gila-monsters (Heloderma). It grows up to 3 - 3,5 meters long, weights up to 200 kg, the male is longer and more thin, the female is shorter, but more massive. Body is short and wide, head is massive, tail is thick, serving for accumulating of fat stock for the period of hibernation. Colouring of skin varies, representing the combination of irregular-shaped spots forming cross strips; primary colors are sandy-yellow and dark brown. Scales forms some longitudinal lines of large scutes along back and crest along the ridge. Paws are sharp-clawed, five-fingered, they are partially shifted under the body. This predator eats large vertebrates, sometimes gathering carrion. Teeth are conic, on third pair of teeth of the top jaw there are the longitudinal grooves connected with poisonous glands. At the sting in a body of prey strong neurotoxic poison flows, killing for half an hour an animal weight up to 200 kg. The lizard puts to catch the sting then it lets off prey and departs aside, pursuing the bitten animal at walk and waiting while it will die. The animal tears catch off to pieces by claws and teeth. The female lays in small hole up to 10 eggs in weight on 200 grammes, during incubating time it protects nest area. Young lizards (their length is up to 30 cm) hatch at the end of one summer. The first winter they will spend in holes of rodents, further dig their own ones. Lizard lives up to 90 - 100 years. For winter it falls to hibernation in shelter: the big hole which is updated from year to year and is used till many years. During the winter hole entrance is closed with the big ball of grass and bushes.