Reptilia · Testudines
Kinosternon stejnegeriHartweg, 1938
Arizona Mud Turtle
Photograph by Richard Fray, CC BY, via iNaturalist
A day-active, meat-eating turtle from the Nearctic region, reaching 18 cm across the shell.
Reptilia › Testudines › Kinosternidae › Kinosternon
- Grows to
- 152.7mm
- greatest recorded
- Eats
- Carnivorous
- Active
- Diurnal
- Lives up to
- 25years
Longer than only 41% of all species in Kinosternidae 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 114 to 380 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
31 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
- Conservation status
- Near Threatened
- Population trend
- Stable
as reported by the IUCN Red List
The animal itself
- Colour on the back
- Brown
- Pattern on the back
- Uniform
- Pupil
- Round
- Venomous
- No
- Fangs
- None
- Longest recorded life
- 25years
- Body temperature when active · measured in the wild
- 24.9°C77 °F
- Body temp in the wild · mean, when active
- 22–27.8°C72–82 °F
mean body temperature of active individuals in nature
body temperature of active animals in nature
Size
- Length nose to tail · greatest recorded
- 152.7mm6 in
- Shell length, front to back · greatest recorded
- 181.3mm7.25 in
- Largest female · shell length
- 167.3mm6.5 in
- Largest male · shell length
- 181.3mm7.25 in
- Largest juvenile · shell length
- 28mm1 in
total length, tail included — Colston, Kulkarni, Jetz, and Pyron, 2020, BMC Evol. Biol., 20:81
straight carapace length, measured in a line rather than over the curve
straight carapace length; the source column mixes this with snout-vent length
How it lives
- Diet
- Carnivorous
- How it hunts
- Active foraging
- Active
- Diurnal
- Where it lives
- Aquatic, terrestrial
- Habitat
- Desert
- Region
- Nearctic
- Elevation · above sea level
- 200–800m
Amphibians, invertebrates
Breeding
- Reproduction
- Oviparous
- Sex decided by
- Temperature
- Average clutch
- 5eggs
- Eggs or young per clutch
- 3–7eggs
- Clutches in a year
- 3per year
Naming and history
- Subspecies
- No
- Described by
- Hartweg
- Moved to another genus · since it was first described
- No
- Described in
- 1938
Keeping one
21.5 in × 10.5 in(54 × 27 cm)
Minimum floor length × width, for one animal. Bigger is always better. The standard sets no height for turtles and tortoises.
The standard sizes this genus at 3 times carapace length, with the width half the resulting length.
For a third and fourth turtle the standard asks for at least 10% more floor area each, and 20% more from the fifth onwards.
Water depth is set against the animal's carapace width rather than its length, so no figure is given here. Dry-country tortoises need no water area, only occasional bathing; tortoises from wetter regions need a water dish.
Swiss law reaches the same 8 × 4 of carapace length for land tortoises, arrived at separately from the German gutachten.
Gutachten über Mindestanforderungen an die Haltung von Reptilien (Sachverständigengruppe tierschutzgerechte Haltung von Terrarientieren), German Federal Ministry, 10 January 1997, section 5. The standard states these are recommendations rather than binding limits.
Swiss Tierschutzverordnung (TSchV), SR 455.1, Anhang 2, Tabelle 5 — legally binding minimum enclosure sizes, which give every land tortoise 8 × 4 body lengths for two animals.
From this animal’s own carapace length of 7.25 in (181.3 mm), at 3 times it — how this is worked out.
Active animals measured in the wild averaged 77 °F (24.9 °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.
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.
- — Still living
- — Length snout to vent · greatest recorded
- — Length snout to vent · adult female mean
- — Length snout to vent · adult male mean
- — Length snout to vent · adult mean
- — 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
- — Hatchling length · snout to vent
- — Hatchling length · nose to tail
- — Largest juvenile · snout to vent
- — Egg length
- — Egg width
- — Body mass · greatest
- — 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 the young develop
- — Gestation or incubation
- — Mean clutch · smallest reported
- — Mean clutch · largest reported
- — 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
- — Limbs
- — Status assessed · the year the Red List last looked
- — Red List criteria
- — Biome
- — Active season · shortest recorded
- — Active season · longest recorded
- — Density · lowest recorded
- — Density · highest recorded
- — Home range · largest recorded
- — Suborder
- — Infraorder
- — Type locality
- — Active in
- — Mainland or island
- — Range size
Others in Kinosternidae
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). Kinosternon stejnegeri. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/kinosternon-stejnegeri
@misc{kinosternon_stejnegeri_2026,
title = {Kinosternon stejnegeri},
author = {{The Reptile & Amphibian Encyclopedia}},
year = {2026},
url = {https://www.allanglescreatures.com/species/kinosternon-stejnegeri}
}Sources
- Oskyrko, O. et al. (2024). ReptTraits: a comprehensive dataset of ecological traits in reptiles. Scientific Data. Used under CC BY 4.0.
- GBIF Secretariat. GBIF Backbone Taxonomy. Used under CC BY 4.0. Common names aggregated from constituent checklists.
- Catalogue of Life (dataset 3LR), used under CC BY.
- Moura, M. R. et al. TetrapodTraits: a database of 33,281 tetrapod species. Used under CC BY 4.0. Observed values only; this encyclopedia does not publish its imputed predictions.