Reptilia · Squamata
Hyalosaurus koellikeriGünther, 1873
Koelliker's Glass Lizard
Photograph by Joey Bom, CC BY, via iNaturalist
An active by day or night, meat-eating lizard from the Saharo-Sindian region, reaching 183 mm snout to vent.
Once published as Ophisaurus koellikeri — those names reach this page.
Reptilia › Squamata › Anguidae › Hyalosaurus
- Grows to
- 183.3mm
- greatest recorded
- Eats
- Carnivorous
- Active
- Cathemeral
- Lives up to
- 9.3years
Longer than 77% of all species in Anguidae 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 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
32 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
- 2009
The animal itself
- Limbs
- Hind legs only
- Venomous
- No
- Fangs
- None
- Longest recorded life
- 9.3years
- Body temperature when active · measured in the wild
- 18°C64 °F
- Body temp in the wild · mean, when active
- 18°C
Carey and Judge 2000, Slavens and Slavens 1999
mean body temperature of active individuals in nature
body temperature of active animals in nature
Size
- Length snout to vent · greatest recorded
- 183.3mm7.25 in
- Hatchling length · snout to vent
- 54mm2.25 in
- Largest juvenile · snout to vent
- 54mm2.25 in
- Body mass · greatestcomputed
- 24.28g0.86 oz
max 183.3 mm SVL (Feldman et al. 2016)
computed from length by a family-level allometric equation, not weighed
How it lives
- Diet
- Carnivorous
- Active
- Cathemeral
- Where it lives
- Fossorial, terrestrial
- Habitat
- Forest, Grassland, Shrubland
- Biome
- Mediterranean
- Region
- Saharo-Sindian
- Mainland or island
- Mainland
- Elevation · above sea level
- 50–1900m
- Range size
- 118,269km²
- Density
- 20per hectare
Insects / earthworms snails and slugs (del Marmol et al. 2019)
Diurnal / basking especially in the early morning (del Marmol et al. 2019), cathemeral (Rodda 2020)
Terrestrial / partially fossorial" (del Marmol et al. 2019)
50-1900 (del Marmol et al. 2019)
Breeding
- Reproduction
- Oviparous
- Clutches a year
- 1per year
IUCN
Naming and history
- Suborder
- Sauria
- Infraorder
- Anguimoprha
- Subspecies
- No
- Described by
- Günther
- Moved to another genus · since it was first described
- No
- Described in
- 1873
- Type locality
- Unknown
Keeping one
2 ft 5 in × 2 ft 5 in × 18 in(73 × 73 × 46 cm)
Minimum length × width × height, for one animal. Bigger is always better. Substrate at least 3.5 in (9 cm) deep.
The standard sizes ground-dwelling species at 4 × 4 × 2.5 times snout-vent length.
Burrows, so substrate deep enough to dig in matters as much as floor area.
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 7.25 in (183.3 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 64 °F (18 °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.
3kJ per day
Worked out for an animal of 24 g, the heaviest recorded for Koelliker's Glass 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 female mean
- — 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 female · snout to vent
- — 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
- — Preferred body temperature · chosen in a laboratory gradient
- — 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
- — 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
- — Population trend
- — Red List criteria
- — Active season · shortest recorded
- — Active season · longest recorded
- — Home range · largest recorded
- — Active in
Others in Anguidae
- Anzuetoi Arboreal Alligator Lizard
- Argueta Arboreal Alligator Lizard
- Asian Glass Lizard
- Baja California Legless Lizard
- Bakersfield Legless Lizard
- Banded Arboreal Alligator Lizard
- Bogert's Arboreal Alligator Lizard
- Brilliant Arboreal Alligator Lizard
- Buettikofer's Glass Lizard
- California Legless Lizard
- Campbell's Alligator Lizard
- Cedros Island Alligator Lizard
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). Hyalosaurus koellikeri. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/hyalosaurus-koellikeri
@misc{hyalosaurus_koellikeri_2026,
title = {Hyalosaurus koellikeri},
author = {{The Reptile & Amphibian Encyclopedia}},
year = {2026},
url = {https://www.allanglescreatures.com/species/hyalosaurus-koellikeri}
}Sources
- Meiri, S. (2024). SquamBase — a database of squamate (Reptilia: Squamata) traits. Global Ecology and Biogeography. Public domain (CC0).
- Catalogue of Life (dataset 3LR), used under CC BY.
- Oskyrko, O. et al. (2024). ReptTraits: a comprehensive dataset of ecological traits in reptiles. Scientific Data. Used under CC BY 4.0.