Reptilia · Squamata
Uma exsulSchmidt & Bogert, 1947
Fringe-toed Sand Lizard
Photograph placed in the public domain, CC0, via iNaturalist
A ground-dwelling, day-active, omnivorous lizard from the Nearctic region, reaching 100 mm snout to vent.
Reptilia › Squamata › Phrynosomatidae › Uma
- Grows to
- 100mm
- greatest recorded
- Eats
- Omnivorous
- Active
- Diurnal
- Lives
- Terrestrial
Longer than 68% of all species in Phrynosomatidae 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 47 to 175 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
43 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
- Endangered
- Status assessed · the year the Red List last looked
- 2007
- Population trend
- Decreasing
- Red List criteria
- B2ab(iii)
The animal itself
- Limbs
- Four legs
- Venomous
- No
- Fangs
- None
- Preferred body temperature · chosen in a laboratory gradientmeasured
- 36.3°C
- Body temperature when active · measured in the wild
- 36.9°C98 °F
- Body temp in the wild · mean, when active
- 35.1–38.7°C95–102 °F
mean body temperature of active individuals in nature
body temperature of active animals in nature
Size
- Length snout to vent · greatest recorded
- 100mm4 in
- Length snout to vent · adult female mean
- 65.3mm2.5 in
- Largest female · snout to vent
- 65.3mm2.5 in
- Hatchling length · snout to vent
- 33mm1.25 in
- Largest juvenile · snout to vent
- 33.5mm1.25 in
- Body mass · greatestcomputed
- 31.55g1.1 oz
max 100 mm (e.g., Heimes 2022)
snout-vent length; the source column mixes this with straight carapace length
computed from length by a family-level allometric equation, not weighed
How it lives
- Diet
- Omnivorous
- How it hunts
- Sit and wait
- Active
- Diurnal
- Where it lives
- Terrestrial
- Habitat
- Desert
- Biome
- Deserts & Xeric Shrublands
- Active season · months of the year
- 8–12months
- Region
- Nearctic
- Mainland or island
- Mainland
- Elevation · above sea level
- 1020–1220m
- Range size
- 10,958km²
- Density
- 2.5–24per hectare
- Home range · largest recorded
- 988m2
arthropods (Barbault and Maury 1981) / omnivore (Cooper et al. 2013), insects and plants (Heimes 2022)
Active foraging (e.g., Pough et al. 1978) / sit and wait (Aguirre and Gatica 2010, Cooper et al. 2013, Shenbrot et al. 1991, Butler 2005)
Terrestrial, occasionally, sand swimming (Commins and Savitzky 1973), terrestrial (Heimes 2022)
about 1100 (Heimes 2022)
Breeding
- Reproduction
- Oviparous
- Average clutch
- 2.75eggs
- Eggs or young per clutch
- 1–6eggs
- Mean clutch
- 2.5–3eggs
- Clutches a year
- 1–3per year
- First breeds at
- 7–12months
1-5, means 2.5-3 (Aguirre and Gatica 2010), max 5 (Heimes 2022), Dominguez-Guerrero et al. 2022 (mean 3)
Naming and history
- Suborder
- Sauria
- Infraorder
- Pleurodonta
- Subspecies
- No
- Described by
- Schmidt & Bogert
- Moved to another genus · since it was first described
- No
- Described in
- 1947
- Type locality
- Mexico
Keeping one
Fringe-toed Sand Lizard is assessed as Endangered on the IUCN Red List. Species at risk in the wild are often covered by CITES and by national law, which decide what may be bought, sold, moved across a border or kept at all — and captive-bred and wild-caught animals are usually treated differently. Check the rules where you are before acquiring one. Nothing below is a judgement about keeping this species; it is what a published welfare standard says about space, and what the animal itself was measured doing.
15.5 in × 15.5 in × 9.75 in(40 × 40 × 25 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 4 in (100 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 97 °F (36.3 °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.
4kJ per day
Worked out for an animal of 32 g, the heaviest recorded for Fringe-toed Sand 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 · a typical adult
- — Body mass · adult female, mean
- — Body mass at hatching
- — Longest recorded life
- — Eats arthropods
- — Eats vertebrates
- — Eats plant matter
- — How the young develop
- — Gestation or incubation
- — Clutches in a year
- — 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
- — Active in
Others in Phrynosomatidae
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). Uma exsul. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/uma-exsul
@misc{uma_exsul_2026,
title = {Uma exsul},
author = {{The Reptile & Amphibian Encyclopedia}},
year = {2026},
url = {https://www.allanglescreatures.com/species/uma-exsul}
}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.