Size: Length; 45-90 cm. Weight; 1.4-4 kg. Males tend to be slightly larger than the females.

Habitat and Distribution: Found in tropical deciduous forest and thorn scrub forest, only in the drainage basins of the Rio Fuerte and Rio Mayo rivers in Mexico.

Age: 30-50 years.

Groups and Breeding: Breeding takes place in February and March, when the female lays and buries 3-13 eggs about 12 cm under ground. Incubation of the eggs takes between 165-215 days and the young can take a further 2-3 days to work their way out of the eggs.

Diet: Small mammals, birds, lizards, frogs and reptile and bird eggs.

• This is one of only two venomous lizards in the world; the other is the Gila Monster. The venom glands are situated in the lower jaw and the poison is delivered via specially grooved teeth as the lizard chews. In laboratory tests, the venom has been shown to be as powerful as some rattle snake poison. Indeed, the bite is extremely painful and can be potentially fatal in small or weak humans.
• Its Latin name Heloderma horridum means horrible studded lizard!
• Heloderm lizards’ skin is made up of tiny beads called ostioderms. Each bead contains a tiny piece of bone that gives them an armour plated skin.
• Locals used to believe that the breath of this lizard was poisonous.
• When food is scarce, the Mexican Beaded Lizard lives off fat reserves in the tail. Fat is stored in the tail of the lizard making it appear swollen. After the fat reserves are used up the tail appears thin again.
• The Gila Monster and Beaded Lizard are the sole survivors of an ancient group of predacious lizards called the Monstersauria.