Gila monster

Scientific Name: Heloderma suspectum

Don’t worry, it’s not really a monster! Although Gila monsters are venomous lizards, they are so slow moving they pose little threat to humans. The only venomous lizard of the United States, the Gila monster is named after the Gila River in Arizona where is it was once common. The lizards grow to 60 centimetres, and have a solid body with blunted tail and head. Their bodies are patterned with blotches, bars and spots that can be light yellow, pink or orange on a grey background. Their scaling in some parts almost looks like beadwork. From November to January-February, Gila monsters hibernate.


Gila monsters are found in south-west United States and northern Mexico in deserts, scrubland and open woodland. They shelter from the heat of the day in burrows or under rock ledges.


Mainly eggs but also small birds, frogs, lizards, mammals and insects. They will also eat carrion (dead animals). Gila monsters have a strong sense of smell and will often dig to locate eggs.


The lizards mate in May-June and females lay a clutch of 2-12 eggs in July-August. These are buried about 12 centimetres deep in the sand and incubate for nine months.