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Squamata · XenosauridaeEntry 21,456 of 21,572
Xenosaurus fractus

Reptilia · Squamata

Xenosaurus fractusNieto-Montes de Oca, Sánchez-Vega, Durán-Fuentes, 2018

Photograph by (Photographs by Luis Canseco Márquez) Nieto-Montes de Oca…, CC BY, via Wikimedia Commons

A rock-dwelling, day-active, omnivorous lizard from the Neotropic region, reaching 123 mm snout to vent.

No English name has been recorded for this species.

Reptilia › Squamata › Xenosauridae › Xenosaurus

Grows to
122.9mm
greatest recorded
Eats
Omnivorous
Active
Diurnal
Lives
Saxicolous

What is known

26 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

The animal itself

Limbs
Four legs
Venomous
No
Fangs
None
Preferred body temperature · chosen in a laboratory gradientmeasured
21.7–22°C71–72 °F
Body temp in the wild · mean, when active
18.5–19.7°C65–67 °F

body temperature of active animals in nature

Size

Length snout to vent · greatest recorded
122.9mm4.75 in

Shai Meiri, unpublished

Length snout to vent · adult female mean
103mm4 in
Largest female · snout to vent
117.2mm4.5 in

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

Body mass · greatestcomputed
42.5g1.5 oz

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

How it lives

Diet
Omnivorous

"primarily of insects and spiders with some vegetative material and did not appear to differ between males and females (Table 3). In particular, larval Lepidopterans had the highest importance value. Vegetative materials were consistently the second most important stomach item. Orthopterans and coleopterans were next in importance." (Woolrich-Pina et al. 2020)

Active
Diurnal

(inferred from Woolrich-Pina et al. 2020: "Lizards (n=65) were captured by hand from 0900 to 1700 h" - and then "We also measured body temperature (Tb; to the nearest 0.2°C) with a quick-reading cloacal thermometer immediately upon capture")

Where it lives
Saxicolous

(de Oca et al. 2018), "Xenosaurus, especially, are very rarely seen outside their crevices" (Woolrich-Pina et al. 2021)

Biome
Tropical & Subtropical Moist Broadleaf Forests
Region
Neotropic
Mainland or island
Mainland
Elevation · above sea level
850–1700m

850-1470 (de Oca et al. 2018), 1700 (Woolrich-Pina et al. 2020)

Range size
98km²

Breeding

Reproduction
Viviparous

Naming and history

Suborder
Sauria
Infraorder
Anguimoprha
Subspecies
No
Described by
Nieto-Montes de Oca, Sánchez-Vega, Durán-Fuentes
Moved to another genus · since it was first described
No
Described in
2018
Type locality
Mexico

Keeping one

19.5 in × 19.5 in × 12 in(49 × 49 × 31 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.

Lives on rock, so stable hard surfaces and basking ledges suit it.

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 4.75 in (122.9 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 71–72 °F (21.7–22 °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.

5kJ per day

Worked out for an animal of 43 g, the heaviest recorded for Xenosaurus fractus — 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 · snout to vent
  • — Hatchling length · nose to tail
  • — Largest juvenile · snout to vent
  • — Largest juvenile · shell length
  • — Egg length
  • — Egg width
  • — Body mass · a typical adult
  • — Body mass · adult female, mean
  • — Body mass at hatching
  • — Longest recorded life
  • — 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
  • — Average clutch
  • — Smallest clutch recorded
  • — Largest clutch recorded
  • — Mean clutch · smallest reported
  • — Mean clutch · largest reported
  • — 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
  • — Colour on the back
  • — Pattern on the back
  • — Pupil
  • — Sex decided by
  • — Conservation status
  • — Status assessed · the year the Red List last looked
  • — Population trend
  • — Red List criteria
  • — Active season · shortest recorded
  • — Active season · longest recorded
  • — Density · lowest recorded
  • — Density · highest recorded
  • — Home range · largest recorded
  • — Habitat
  • — Active in

Others in Xenosauridae

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). Xenosaurus fractus. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/xenosaurus-fractus

@misc{xenosaurus_fractus_2026,
  title  = {Xenosaurus fractus},
  author = {{The Reptile & Amphibian Encyclopedia}},
  year   = {2026},
  url    = {https://www.allanglescreatures.com/species/xenosaurus-fractus}
}

Sources

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