There are approx. 3000 different species of lizards, but fortunately only two of them are venomous. These 2 venomous ones are the beaded lizard (Heloderma horridum) of southwestern Mexico and the gila monster (Heloderma suspectum) of southern Arizona and New Mexico. These reptiles may be identified by their tuberculated skin, stumpy tails and colouring. Gila monsters are mottled salmon pink and black, whereas beaded lizards are black and yellow. They are usually 20-30 inches(=50-75 cm) in length. Fortunately, they seldom attack people, but when they do so they bite tenaciously. Their venom is not injected into the wound, as is the case with snakes, but merely flows into it. Paralysis, difficulty in breathing and convulsions may occur, but fatalities are extremely rare.