The Wonderful World of the Beaded Lizards

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Scientific Name:  Heloderma horridum
Range: Mexico and Guatemala
Habitat: Tropical, dry forests
Status: Near extinction
Diet in the wild: Rodents, birds, and the eggs of other reptiles
Diet in the zoo: Eggs of hens 
Location in the zoo:  Herpetarium

Physical description: 
The head is broad and slightly flattened, and is joined with a short neck and an elongated, cylindrical body, ending with a thick, rounded tail. The legs are short but powerful; each foot has five clawed toes. The back is covered with large, bony scales. The belly is in contrast, bears flat, regularly arranged scales that are hardly ossified. The teeth curve slightly backward and are set somewhat inward from the edge of the jaws. The lower jaw teeth have single grooves on the front and back that permit the venom to flow into the wound.


Found in dry, open forest areas with abundant rocks and sparse vegetation. Burrows to avoid the mid-day heat. 

Carnivorous. Eats insects, spiders, other small invertebrates, lizards, snakes, rodents, birds and eggs. Primarily terrestrial. They are frequently found in abandoned mammal burrows and near sources of permanent water. Preyed upon by large mammals and birds of prey. 

Life History 

Mating occurs mostly in the spring. 3-13 long eggs laid in mid-late summer buried in sand at a depth of about 5 in. Incubation 117-130 days.

Special Adaptations  

  • Paired salivary glands produce a venom injected through a groove in the teeth that paralyzes prey. 
  • Must chew their victim in order to inject poison. 
  • The tail is used to store energy for times when food is scarce. 
  • Long claws for digging.  

Related Links:

Beaded Lizard at the 
Houston Zoo

Mexican Beaded Lizard at the
San Antonio Zoo

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Reptiles and Amphibian Index

Source list:
Wild Life the World Over by: E.G. Boulenger, F.Z.S as well as Grzimek Animal Encyclopedia