Rio Fuerte Beaded Lizard

Rio Fuerte Beaded Lizard Heloderma exasperatum

Type of Animal:

Thornscrub, thorn forest, tropical thorn woodland, dry forest, scrubland, tropical deciduous forest, shrubland, pine-oak forest, pine forest, dry deciduous woodland, dried arroyos, washes, desert, desert scrub, scrub forest, chaparral, mountainous areas, rock ledges, sparsely vegetated canyon bottoms, rocky sparsely vegetated areas

S Sonora, N Sinaloa, SW Chihuahua

Stocky lizard w/ broad head, small beadlike scales forming yellow/black stripes, strong forelegs/claws, long tail, blackish to reddish-black base color

Eggs, lizards, small mammals, birds, insects, snakes, frogs, young tortoises, earthworms, carrion

Status in Wild:

Breeding in zoos, wildlife parks, & breeding centers

Solitary or small multi-male, multi-female groups. Male combat often helps trigger breeding, consisting of wrestling/biting.

Additional Info:

Young: Hatchling
Group: Lounge

Male: 3.3 lbs
Female: 2.64 lbs
Young: 1 lb

6-7 months 

Life Span:
20-30 years

Body Length:
Male: 2.5 ft
Female: 2.2 ft
Young: 1.7 ft

Tail Length:
Male: 1.25 ft
Female: 1.1 ft

Main predators of adults are coyotes, raptors, foxes, pumas, & bobcats. Rattlesnakes eat young. Many animals eat eggs.
Spend much of their time underground or in sheltered areas.
They’re very sluggish, only biting if provoked.
Coloration may serve as warning.
Venom produced in modified salivary glands in lower jaw & often chewed into victims w/ bulldog-like tenacity. Venom used for killing prey as well as defense.
When food scarce, they can metabolize fat stored in tail.
Females lay 2-30 eggs per clutch.
These lizards are good climbers.
These lizards spend cooler months hibernating & in months when active, often only active for an hour.
Sexually mature at 2-3 years old.
Can go w/o food for long periods of time.
All prey besides eggs & carrion swallowed whole.

Fun Fact(s):
These lizards often killed on sight due to superstitions such as being more venomous than rattlesnakes, causing lightning strikes w/ tails, and/or causing pregnant women to miscarry by simply looking at them.
Bites from these lizards can cause pain lasting more than a day as well as edema, hypotension, nausea, vomiting, weakness, & diaphoresis. 1st line of defense is hissing.
Venom found to have several enzymes useful for possibly treating diabetes, Alzheimer’s & HIV.

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