Reptilia · Squamata
Heloderma horridumWiegmann, 1829
Mexican Beaded Lizard
Photograph by David Rubin, CC BY, via Wikimedia Commons
A ground-dwelling, active by day or night, meat-eating lizard from the Neotropic region, reaching 520 mm snout to vent.
Reptilia › Squamata › Helodermatidae › Heloderma
- Grows to
- 520mm
- greatest recorded
- Eats
- Carnivorous
- Active
- Cathemeral
- Lives up to
- 44years
What is known
48 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
- 44years
- Preferred body temperature · chosen in a laboratory gradientmeasured
- 29–30°C84–86 °F
- Body temperature when active · measured in the wild
- 29.5°C85 °F
- Body temp in the wild · mean, when active
- 28.8–30.2°C84–86 °F
Carey and Judge 2000, De Magalhaes & Costa 2009, Slavens and Slavens 1999, see Bogert and Martin del Campo 1956, Beck 2005: 37, Mitchell 2006: 44 (captivity); Petzold 2008: 17
mean body temperature of active individuals in nature
body temperature of active animals in nature
Size
- Length snout to vent · greatest recorded
- 520mm20.5 in
- Length snout to vent · adult female mean
- 363.9mm14.5 in
- Largest female · snout to vent
- 363.9mm14.5 in
- Hatchling length · snout to vent
- 121mm4.75 in
- Largest juvenile · snout to vent
- 121mm4.75 in
- Body mass · greatestcomputed
- 3046.7g6.7 lb
- Body mass · a typical adult
- 1244.2g2.7 lb
- Body mass · adult female, meanmeasured
- 2728g6 lb
- Body mass at hatchingmeasured
- 30.5g1.1 oz
max 520 mm SVL (Feldman et al. 2016)
snout-vent length; the source column mixes this with straight carapace length
computed from length by a family-level allometric equation, not weighed
AnAge rates this record "acceptable"
How it lives
- Diet
- Carnivorous
- How it hunts
- Active foraging
- Active
- Cathemeral
- Where it lives
- Terrestrial
- Habitat
- Forest, Shrubland
- Biome
- Tropical & Subtropical Dry Broadleaf Forests
- Active season · months of the year
- 12months
- Region
- Neotropic
- Mainland or island
- Mainland
- Highest it lives · above sea level
- 2110m
- Range size
- 171,126km²
- Density
- 0.08–0.15per hectare
- Home range · largest recorded
- 1,985,000m2
Arthropods, lizards, mammals, nestlings and eggs / mammals, birds, eggs but does not intentionally take insects (Bogert and Martin del Campo 1956 p109)
Active foraging
Crepuscular and Diurnal / Crepuscular and nocturnal (Kohler 2008) / crepuscular (Hardy and McDiarmid 1969), cathemeral, mostly crepuscular (Lemos-Espinal and Smith 2007b, Lemos-Espinal et al. 2013),
35-1560 (Rorabaugh and Lemos-Espinal 2016), 2108 (Ariano-Sanchez et al. 2022)
Breeding
- Reproduction
- Oviparous
- Sex decided by
- Genes, ZW/ZZ
- Average clutch
- 8eggs
- Eggs or young per clutch
- 2–22eggs
- Mean clutch
- 7–9eggs
- Clutches in a year
- 1per year
- Clutches a year
- 0.5–1per year
- First breeds at
- 84months
24 (Van Wilgen and Richardson 2012), 2-22 in captivity, 4-8 in nature (Ariano-Sanchez and Salazar 2015), 3-15 (Otsuka et al. 2020)
Naming and history
- Suborder
- Sauria
- Infraorder
- Anguimoprha
- Subspecies
- No
- Described by
- Wiegmann
- Moved to another genus · since it was first described
- Yes
- Described in
- 1829
- Type locality
- Mexico
Keeping one
6 ft 10 in × 6 ft 10 in × 4 ft 3 in(208 × 208 × 130 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 20.5 in (520 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.
245kJ per day
Worked out for an animal of 3,047 g, the heaviest recorded for Mexican 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 male · snout to vent
- — Largest female · shell length
- — Largest male · shell length
- — Hatchling length · nose to tail
- — Largest juvenile · shell length
- — Egg length
- — Egg width
- — Eats arthropods
- — Eats vertebrates
- — Eats plant matter
- — How the young develop
- — Gestation or incubation
- — 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
- — Colour on the back
- — Pattern on the back
- — Pupil
- — Red List criteria
- — Active in
- — Lowest it lives · above sea level
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 horridum. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/heloderma-horridum
@misc{heloderma_horridum_2026,
title = {Heloderma horridum},
author = {{The Reptile & Amphibian Encyclopedia}},
year = {2026},
url = {https://www.allanglescreatures.com/species/heloderma-horridum}
}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.
- AnAge, Human Ageing Genomic Resources (de Magalhães et al.), used under CC BY 3.0.