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Squamata · AnguidaeEntry 7,516 of 21,572
Madrean Alligator Lizard, Elgaria kingii

Reptilia · Squamata

Elgaria kingiiGray, 1838

Madrean Alligator Lizard

Photograph by Marshal Hedin from San Diego, CC BY-SA, via Wikimedia Commons

A ground-dwelling, day-active, meat-eating lizard from the Nearctic region, reaching 140 mm snout to vent.

Also called Arizona Alligator Lizard.

Once published as Elgaria usafa, Gerrhonotus kingi — those names reach this page.

ReptiliaSquamataAnguidaeElgaria

Grows to
140mm
greatest recorded
Eats
Carnivorous
Active
Diurnal
Lives up to
15years
Body length across Anguidae

Longer than 57% of all species in Anguidae anyone has measured.

57% of 86 species are smaller43% larger
72 mmthe whole family, smallest to largest610 mm

The bar is the rank itself: its length is the share of the family this animal exceeds. The chart below is the family’s real spread, on a logarithmic scale because body length here runs from 72 to 610 mm. The solid rule is this animal. Every bar is a count of real species, and nothing on this figure is estimated.

What is known

41 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
2007
Population trend
Stable

The animal itself

Limbs
Four legs
Venomous
No
Fangs
None
Longest recorded life
15years

Carey and Judge 2000, more than 15 (Degenhardt et al. 1996), Slavens and Slavens 1999: 12.33

Body temperature when active · measured in the wild
34.15°C93 °F

mean body temperature of active individuals in nature

Body temp in the wild · mean, when active
34–34.3°C93–94 °F

body temperature of active animals in nature

Size

Length snout to vent · greatest recorded
140mm5.5 in

max 140 mm SVL (Feldman et al. 2016)

Length snout to vent · adult female mean
109mm4.25 in
Largest female · snout to vent
109mm4.25 in

snout-vent length; the source column mixes this with straight carapace length

Hatchling length · snout to vent
33mm1.25 in
Largest juvenile · snout to vent
33mm1.25 in
Body mass · greatestcomputed
50.53g1.8 oz

computed from length by a family-level allometric equation, not weighed

Body mass · a typical adult
10g0.35 oz

AnAge rates this record "acceptable"

How it lives

Diet
Carnivorous

Invertebrates (arthropods, Lemos-Espinal et al. 2013, Rorabaugh and Lemos-Espinal 2016, Stebbins and McGinnis 2018)

How it hunts
Active foraging

"forager" (Lemos-Espinal et al. 2013), active (Scales and Butler 2015)

Active
Diurnal

"sometimes abroad at dusk or after dark" (Stebbins 2003), Diurnal (Degenhardt et al. 1996, Lemos-Espinal and Smith 2007b, Lemos-Espinal et al. 2013, Cruz-Saenz et al. 2008), mostly diurnal, also active on warm evenings (Jones and Lovich 2009), diurnal and crepuscular (Rorabaugh and Lemos-Espinal 2016)

Where it lives
Cryptic, terrestrial

Terrestrial, Cryptic/terrestrial (Cruz-Saenz et al. 2008), chiefly ground dwelling, ocassionally climb (Stebbins and McGinnis 2018)

Habitat
Desert, Forest, Grassland, Shrubland
Biome
Tropical & Subtropical Coniferous Forests
Active season · months of the year
7months
Region
Nearctic
Mainland or island
Mainland
Elevation · above sea level
730–2770m

up to 2675 (Lemos-Espinal et al. 2013), 730-2770 (Stebbins and McGinnis 2018)

Range size
305,396km²

Breeding

Reproduction
Oviparous
Average clutch
12eggs
Eggs or young per clutch
9–15eggs

9-15 (Zaldivar Riveron et al. 2002, Stebbins and McGinnis 2018), 12-15 (Lemos-Espinal et al. 2013, Rorabaugh and Lemos-Espinal 2016)

Mean clutch
12eggs
Clutches in a year
1per year
Clutches a year
1per year

Naming and history

Suborder
Sauria
Infraorder
Anguimoprha
Subspecies
Elgaria kingii kingii GRAY 1838 Elgaria kingii nobilis BAIRD & GIRARD 1852 Elgaria kingii ferruginea (WEBB 1962)
Described by
Gray
Moved to another genus · since it was first described
No
Described in
1838
Type locality
Mexico

Keeping one

22 in × 22 in × 14 in(56 × 56 × 35 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 5.5 in (140 mm), at 4 × 4 × 2.5 times it, following the German federal welfare standard — how this is worked out.

Active animals measured in the wild averaged 94 °F (34.2 °C).

Mean body temperature of active individuals measured in nature. 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.

6kJ per day

Worked out for an animal of 51 g, the heaviest recorded for Madrean Alligator 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
  • Body mass · adult female, mean
  • Body mass at hatching
  • Preferred body temperature · chosen in a laboratory gradient
  • Eats arthropods
  • Eats vertebrates
  • Eats plant matter
  • How the young develop
  • Gestation or incubation
  • 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
  • Colour on the back
  • Pattern on the back
  • Pupil
  • Sex decided by
  • Red List criteria
  • Density · lowest recorded
  • Density · highest recorded
  • Home range · largest recorded
  • Active in

Others in Anguidae

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). Elgaria kingii. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/elgaria-kingii

@misc{elgaria_kingii_2026,
  title  = {Elgaria kingii},
  author = {{The Reptile & Amphibian Encyclopedia}},
  year   = {2026},
  url    = {https://www.allanglescreatures.com/species/elgaria-kingii}
}

Sources

  1. Meiri, S. (2024). SquamBase — a database of squamate (Reptilia: Squamata) traits. Global Ecology and Biogeography. Public domain (CC0).
  2. Oskyrko, O. et al. (2024). ReptTraits: a comprehensive dataset of ecological traits in reptiles. Scientific Data. Used under CC BY 4.0.
  3. Catalogue of Life (dataset 3LR), used under CC BY.
  4. AnAge, Human Ageing Genomic Resources (de Magalhães et al.), used under CC BY 3.0.