Reptilia · Testudines
Actinemys marmorataBaird & Girard, 1852
(North-) Western Pond Turtle
Photograph by Zack Abbey, CC BY, via iNaturalist
An active by day or night, omnivorous turtle from the Nearctic region, reaching 21 cm across the shell.
Also called Northern Pacific Pond Turtle.
Reptilia › Testudines › Emydidae › Actinemys
- Grows to
- 210mm
- greatest recorded
- Eats
- Omnivorous
- Active
- Cathemeral
- Lives up to
- 50years
Longer than only 27% of all species in Emydidae 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 shell length here runs from 94 to 400 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
29 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
- Vulnerable
- Population trend
- Unspecified
The animal itself
- Colour on the back
- Brown
- Pattern on the back
- Striped
- Pupil
- Round
- Venomous
- No
- Fangs
- None
- Longest recorded life
- 50years
- Body temperature when active · measured in the wild
- 25.5°C78 °F
- Body temp in the wild · mean, when active
- 21.8–27°C71–81 °F
mean body temperature of active individuals in nature
body temperature of active animals in nature
Size
- Shell length, front to back · greatest recorded
- 210mm8.25 in
- Body mass · greatestcomputed
- 1816g4 lb
- Body mass · a typical adult
- 282g9.9 oz
- Body mass at hatching
- 8.26g0.29 oz
straight carapace length, measured in a line rather than over the curve
largely converted from length by allometry in the source
AnAge rates this record "acceptable"
How it lives
- Diet
- Omnivorous
- How it hunts
- Active foraging
- Active
- Cathemeral
- Where it lives
- Arboreal, saxicolous, terrestrial
- Region
- Nearctic
- Highest it lives · above sea level
- 990m
Amphibians, invertebrates, fish, plants
Breeding
- Reproduction
- Oviparous
- Sex decided by
- Temperature
- Average clutch
- 4eggs
- Eggs or young per clutch
- 5–13eggs
- Clutches in a year
- 1per year
Naming and history
- Subspecies
- No
- Described by
- Baird & Girard
- Moved to another genus · since it was first described
- Yes
- Described in
- 1852
Keeping one
(North-) Western Pond Turtle is assessed as Vulnerable 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.
No enclosure size is given here
The standard sets enclosure size for turtles and tortoises genus by genus, and this genus is not among the roughly sixty it lists. No figure is given rather than one borrowed from a different animal.
Active animals measured in the wild averaged 78 °F (25.5 °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.
155kJ per day
Worked out for an animal of 1,816 g, the heaviest recorded for (North-) Western Pond Turtle — 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.
- — 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
- — 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 · snout to vent
- — Hatchling length · nose to tail
- — Largest juvenile · snout to vent
- — Largest juvenile · shell length
- — Egg length
- — Egg width
- — Body mass · adult female, mean
- — 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
- — Habitat
- — Active in
- — Mainland or island
- — Lowest it lives · above sea level
- — Range size
Others in Emydidae
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). Actinemys marmorata. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/actinemys-marmorata
@misc{actinemys_marmorata_2026,
title = {Actinemys marmorata},
author = {{The Reptile & Amphibian Encyclopedia}},
year = {2026},
url = {https://www.allanglescreatures.com/species/actinemys-marmorata}
}Sources
- 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.