Reptilia · Squamata
Underwoodisaurus miliiBory de Saint-Vincent, 1823
Barking Gecko
Photograph by Greg Tasney, CC BY-SA, via iNaturalist
A ground-dwelling, nocturnal, meat-eating gecko from the Australo-Pacific region, reaching 110 mm snout to vent.
Also called Thick-tailed Gecko.
Once published as Nephrurus milii, Phyllurus milii, Underwoodisaurus husbandi — those names reach this page.
Reptilia › Squamata › Carphodactylidae › Underwoodisaurus
- Grows to
- 110mm
- greatest recorded
- Eats
- Carnivorous
- Active
- Nocturnal
- Lives up to
- 18years
Longer than 53% of all species in Carphodactylidae 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 75 to 160 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
45 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
- 2017
- Population trend
- Stable
The animal itself
- Limbs
- Four legs
- Venomous
- No
- Fangs
- None
- Longest recorded life
- 18years
- Preferred body temperature · chosen in a laboratory gradientmeasured
- 20–27.3°C68–81 °F
- Body temperature when active · measured in the wild
- 18.5°C65 °F
- Body temp in the wild · mean, when active
- 17.6–19.4°C64–67 °F
De Magalhaes & Costa 2009: 12; Werner et al. 1993: 5 years, 5 months; Slavens and Slavens 1999: 12, Brown 2012: exceptional cases of specimens breeding at 18 years of age, Greer 1989: 5
mean body temperature of active individuals in nature
body temperature of active animals in nature
Size
- Length snout to vent · greatest recorded
- 110mm4.25 in
- Length snout to vent · adult female mean
- 81.4mm3.25 in
- Largest female · snout to vent
- 79.2mm3 in
- Hatchling length · snout to vent
- 35.5mm1.5 in
- Largest juvenile · snout to vent
- 35.5mm1.5 in
- Body mass · greatestcomputed
- 26.64g0.94 oz
- Body mass · a typical adult
- 9.6g0.34 oz
- Body mass at hatchingmeasured
- 1.63g0.06 oz
max 110 mm SVL (Feldman et al. 2016), Skipwith and Oliver 2023 (males 70.8-99.54, mean 86.15 mm)
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
- Mixed
- Active
- Nocturnal
- Where it lives
- Terrestrial
- Habitat
- Forest, Rocky, Savanna, Shrubland
- Biome
- Deserts & Xeric Shrublands
- Active season · months of the year
- 6–7months
- Region
- Australo-Pacific
- Mainland or island
- Mainland
- Elevation · above sea level
- 240–250m
- Range size
- 2,778,109km²
Arthropods and small lizards (e.g., Rynchoedura ornata, How et al. 1990), little plant material (How et al. 1990) / mainly vertebrates (Daza et al. 2009), "insects, spiders, scorpions and small lizards" - and eggs (Laube and Porter 2004), mainly arthropods, also vertebrates (Robertson and Coventry 2019)
Brown 2012
(e.g., Robertson and Coventry 2019, Jolly et al. 2023)/ mainly at night but can hunt from ambush during the day at dusk or dawn (Laube and Porter 2004)
(e.g., Read 1999, Wilson and Swan 2010, Shah 2002, Swan et al. 2017, Robertson and Coventry 2019, Kearney 2001)/ saxicolous (Storr et al. 1990)
Breeding
- Reproduction
- Oviparous
- Sex decided by
- Genes, ZW/ZZ
- Average clutch
- 2eggs
- Eggs or young per clutch
- 1–2eggs
- Mean clutch
- 2eggs
- Clutches in a year
- 3per year
- Clutches a year
- 1–8per year
- First breeds at
- 9–24months
1 or 2 (Shah 2002), 2 (Brown 2012, Robertson and Coventry 2019), 2, very rarely 1 (Laube and Porter 2004)
Naming and history
- Suborder
- Sauria
- Infraorder
- Gekkota
- Subspecies
- No
- Described by
- Bory de Saint-Vincent
- Moved to another genus · since it was first described
- Yes
- Described in
- 1823
- Type locality
- Australia
Keeping one
17.5 in × 17.5 in × 11 in(44 × 44 × 28 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 4.25 in (110 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 68–81 °F (20–27.3 °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 27 g, the heaviest recorded for Barking Gecko — 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
- — Red List criteria
- — Density · lowest recorded
- — Density · highest recorded
- — Home range · largest recorded
- — Active in
Others in Carphodactylidae
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). Underwoodisaurus milii. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/underwoodisaurus-milii
@misc{underwoodisaurus_milii_2026,
title = {Underwoodisaurus milii},
author = {{The Reptile & Amphibian Encyclopedia}},
year = {2026},
url = {https://www.allanglescreatures.com/species/underwoodisaurus-milii}
}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.