Reptilia · Squamata
Xantusia vigilisBaird, 1859
Desert Night Lizard
Photograph by CaracalShan, CC BY, via iNaturalist
An active by day or night, meat-eating lizard from the Nearctic region, reaching 70 mm snout to vent.
Also called Sierra Night Lizard, Utah Night Lizard.
Reptilia › Squamata › Xantusiidae › Xantusia
- Grows to
- 70mm
- greatest recorded
- Eats
- Carnivorous
- Active
- Cathemeral
- Lives up to
- 10.9years
Longer than 50% of all species in Xantusiidae anyone has measured.
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 36 to 153 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
44 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
- 10.9years
- Preferred body temperature · chosen in a laboratory gradientmeasured
- 29–33°C84–91 °F
- Body temperature when active · measured in the wild
- 29.05°C84 °F
- Body temp in the wild · mean, when active
- 24.3–33.8°C76–93 °F
Carey and Judge 2000, De Magalhaes & Costa 2009: 10.9, Stebbins and McGinnis 2012: 10; Slavens and Slavens 1999: 10 and 11 months, Zuniga-Vega et al. 2005: 11.5 citing Zweifel and Lowe 1966, but Zweifel and Lowe 1966 doubt this record and give 8.5 for the maximum verified age, 8-10 (While et al. 2019, Whiting and While 2017)
mean body temperature of active individuals in nature
body temperature of active animals in nature
Size
- Length snout to vent · greatest recorded
- 70mm2.75 in
- Length snout to vent · adult female mean
- 42.1mm1.75 in
- Largest female · snout to vent
- 42.1mm1.75 in
- Hatchling length · snout to vent
- 22mm0.9 in
- Largest juvenile · snout to vent
- 22mm0.9 in
- Body mass · greatestcomputed
- 6.73g0.24 oz
- Body mass · a typical adult
- 1.48g0.05 oz
- Body mass at hatchingmeasured
- 0.35g0.01 oz
max 70 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
- Sit and wait
- Active
- Cathemeral
- Where it lives
- Arboreal, saxicolous, terrestrial
- Habitat
- Desert, Forest, Rocky, Shrubland
- Biome
- Deserts & Xeric Shrublands
- Region
- Nearctic
- Mainland or island
- Mainland
- Elevation · above sea level
- 300–2840m
- Range size
- 261,349km²
- Density
- 1.71–16,000per hectare
Arthropods (e.g., Rorabaugh and Lemos-Espinal 2016, Stebbins and McGinnis 2018), insects (Grismer and Grismer 2022)
e.g., Mesquita et al. 2016
Cathemeral: Diurnal and Crepuscular, nocturnal on hot summers (Rogner 1997b) / nocturnal (Huey et al. 2001, Rorabaugh 2008)/chiefly diurnal and Crepuscular, may be nocturnal in warm summer nights (Stebbins and McGinnis 2018), during the day (Grismer and Grismer 2022)
Saxicolous and Leaf Litter / terrestrial (Mesquita et al. 2016) / secretive and leaf litter (Stebbins and McGinnis 2018) / "activity takes place within and beneath the vegetation within which they reside" (Grismer and Grismer 2022)
30-400 (Rorabaugh and Lemos-Espinal 2016)
Breeding
- Reproduction
- Viviparous
- Average clutch
- 1.84eggs
- Eggs or young per clutch
- 1–3eggs
- Mean clutch
- 1.78–1.9eggs
- Clutches in a year
- 1per year
- Clutches a year
- 1per year
- First breeds at
- 33–36months
1-3 (Lemm 2006, Rorabaugh and Lemos-Espinal 2016, Stebbins and McGinnis 2018), mean 1.8 (Pike et al. 2008), mean 1.9 (Bezy and Goldberg 2015), mean 1.78-1.87 (Mesquita et al. 2016), mean 1.87 (Rorabaugh and Lemos-Espinal 2016), 1-2 (Whiting and While 2017), up to 3 (Grismer and Grismer 2022)
Naming and history
- Suborder
- Sauria
- Infraorder
- Scincoidea
- Subspecies
- No
- Described by
- Baird
- Moved to another genus · since it was first described
- No
- Described in
- 1859
- Type locality
- USA
Keeping one
11 in × 11 in × 11 in(28 × 28 × 28 cm)
Minimum length × width × height, for one animal. Bigger is always better.
The standard sizes ground species at 4 × 4 × 2.5 and climbing species at 4 × 2.5 × 4 times snout-vent length.
Recorded both on the ground and climbing, so this is the larger of the two rules in every dimension.
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 2.75 in (70 mm), at 4 × 4 × 4 times it, following the German federal welfare standard — how this is worked out.
In a laboratory thermal gradient this species settled at 84–91 °F (29–33 °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.
1kJ per day
Worked out for an animal of 7 g, the heaviest recorded for Desert Night 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
- — 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
- — Sex decided by
- — Red List criteria
- — Active season · shortest recorded
- — Active season · longest recorded
- — Home range · largest recorded
- — Active in
Others in Xantusiidae
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). Xantusia vigilis. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/xantusia-vigilis
@misc{xantusia_vigilis_2026,
title = {Xantusia vigilis},
author = {{The Reptile & Amphibian Encyclopedia}},
year = {2026},
url = {https://www.allanglescreatures.com/species/xantusia-vigilis}
}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.