Reptilia · Squamata
Heloderma exasperatumBogert & Martin Del Campo, 1956
Río Fuerte Beaded Lizard
Photograph by Zythème, CC0, via Wikimedia Commons
A ground-dwelling, active by day or night, meat-eating lizard from the Nearctic region, reaching 483 mm snout to vent.
Reptilia › Squamata › Helodermatidae › Heloderma
- Grows to
- 483mm
- greatest recorded
- Eats
- Carnivorous
- Active
- Cathemeral
- Lives up to
- 37years
What is known
35 sourced facts, each taken from a named scientific dataset. How to read these.
Cited from a dataset unless a row is marked otherwise.
Standing in the world
- Still living
- Extant
- Conservation status
- Least Concern
- Status assessed · the year the Red List last looked
- 2021
- Population trend
- Decreasing
The animal itself
- Limbs
- Four legs
- Venomous
- Yes
- Fangs
- None
- Longest recorded life
- 37years
- Preferred body temperature · chosen in a laboratory gradientmeasured
- 29–30°C84–86 °F
Beck 2005: 37 (captivity)
Size
- Length snout to vent · greatest recorded
- 483mm19 in
- Length snout to vent · adult female mean
- 352mm14 in
- Hatchling length · snout to vent
- 121mm4.75 in
- Body mass · greatestcomputed
- 2415.5g5.3 lb
- Body mass · adult female, meanmeasured
- 1285g2.8 lb
- Body mass at hatchingmeasured
- 28.2g0.99 oz
Shai Meiri, unpublished
computed from length by a family-level allometric equation, not weighed
How it lives
- Diet
- Carnivorous
- Active
- Cathemeral
- Where it lives
- Terrestrial
- Habitat
- Forest, Shrubland
- Active season · months of the year
- 4–6months
- Region
- Nearctic
- Mainland or island
- Mainland
- Elevation · above sea level
- 35–1560m
mostly eggs and neonates (Rorabaugh and Lemos-Espinal 2016)
(Bogert and Martin del Campo 1956)/mornings, evenings and nights (Rorabaugh and Lemos-Espinal 2016)
35-1560 (Rorabaugh and Lemos-Espinal 2016)
Breeding
- Reproduction
- Oviparous
- Sex decided by
- Genes, ZW/ZZ
- Average clutch
- 11.5eggs
- Eggs or young per clutch
- 2–22eggs
- Mean clutch
- 7–9eggs
2-22, means 7-9 (Rorabaugh and Lemos-Espinal 2016), 7-19 (Otsuka et al. 2020)
Naming and history
- Suborder
- Sauria
- Infraorder
- Anguimoprha
- Subspecies
- No
- Described by
- Bogert & Martin Del Campo
- Moved to another genus · since it was first described
- No
- Described in
- 1956
- Type locality
- Mexico
Keeping one
6 ft 4 in × 6 ft 4 in × 4 ft(193 × 193 × 121 cm)
Minimum length × width × height, for one animal. Bigger is always better.
The standard sizes ground-dwelling species at 4 × 4 × 2.5 times snout-vent length.
Mindestanforderungen an die Haltung von Reptilien (Sachverständigengutachten), German Federal Ministry for Nutrition, Agriculture and Forestry, Animal Welfare Division, 10 January 1997. The standard states these floor areas are recommendations rather than binding limits.
From this animal’s own snout-vent length of 19 in (483 mm), at 4 × 4 × 2.5 times it, following the German federal welfare standard — how this is worked out.
In a laboratory thermal gradient this species settled at 84–86 °F (29–30 °C).
Preferred body temperature, recorded in a laboratory gradient where the animal could choose freely. A measurement of the animal, not a setting for a thermostat.
Feeding
A prey item should be no wider than the space between the animal's eyes.
Widely used across reptile husbandry references. The stated reason is that the gap approximates the width of the throat, so wider prey is associated with impaction. This is established practice, not a measurement.
199kJ per day
Worked out for an animal of 2,416 g, the heaviest recorded for Río Fuerte Beaded Lizard — so it is the top of the range, not a figure for a particular animal. Weigh yours and the number will be lower.
An upper estimate, not a feeding target, and not veterinary advice. The equation covers only what an animal burns staying alive, so a growing, gravid or recovering animal needs more — and it was measured on wild animals, which move far more than one in an enclosure. Body condition and a vet who knows the species are what a feeding decision should rest on. Where this comes from.
What nobody knows
These are not gaps in our research. No scientific dataset records them for this species — and saying so is information you cannot get from a reference that simply leaves a field out.
- — Length snout to vent · adult male mean
- — Length snout to vent · adult mean
- — Length nose to tail · greatest recorded
- — Female length · mean, nose to tail
- — Length nose to tail · adult male mean
- — Length nose to tail · adult mean
- — Largest female · snout to vent
- — Largest male · snout to vent
- — Largest female · shell length
- — Largest male · shell length
- — Hatchling length · nose to tail
- — Largest juvenile · snout to vent
- — Largest juvenile · shell length
- — Egg length
- — Egg width
- — Body mass · a typical adult
- — Body temperature when active · measured in the wild
- — Eats arthropods
- — Eats vertebrates
- — Eats plant matter
- — How it hunts
- — How the young develop
- — Gestation or incubation
- — Clutches in a year
- — Clutches a year · fewest
- — Clutches a year · most
- — First breeds from · youngest recorded
- — First breeds by · oldest recorded
- — Hatchling length · smallest recorded
- — Hatchling length · largest recorded
- — Age at first breeding · female
- — Mature from · youngest recorded
- — Mature by · oldest recorded
- — Size at maturity · smallest recorded
- — Size at maturity · largest recorded
- — Body temp in the wild · lowest mean recorded
- — Body temp in the wild · highest mean recorded
- — Colour on the back
- — Pattern on the back
- — Pupil
- — Red List criteria
- — Biome
- — Density · lowest recorded
- — Density · highest recorded
- — Home range · largest recorded
- — Active in
- — Range size
Others in Helodermatidae
Take this data
Everything on this page is available as data under CC BY 4.0 — use it freely, credit it, no permission needed.
This species as JSON · the whole dataset
Cite this page
The Reptile & Amphibian Encyclopedia (2026). Heloderma exasperatum. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/heloderma-exasperatum
@misc{heloderma_exasperatum_2026,
title = {Heloderma exasperatum},
author = {{The Reptile & Amphibian Encyclopedia}},
year = {2026},
url = {https://www.allanglescreatures.com/species/heloderma-exasperatum}
}Sources
- Meiri, S. (2024). SquamBase — a database of squamate (Reptilia: Squamata) traits. Global Ecology and Biogeography. Public domain (CC0).
- Oskyrko, O. et al. (2024). ReptTraits: a comprehensive dataset of ecological traits in reptiles. Scientific Data. Used under CC BY 4.0.
- Catalogue of Life (dataset 3LR), used under CC BY.