Reptilia · Testudines
Graptemys nigrinodaCagle, 1954
Black-knobbed Sawback
Photograph by Fredlyfish4, CC BY-SA, via Wikimedia Commons
A water-living, active by day or night, meat-eating turtle from the Nearctic region, reaching 19 cm across the shell.
Also called Black-knobbed Map Turtle, Black-knobbed map turtle, black-knobbed map turtle.
Reptilia › Testudines › Emydidae › Graptemys
- Grows to
- 220mm
- greatest recorded
- Eats
- Carnivorous
- Active
- Cathemeral
- Lives up to
- 20.3years
Longer than only 26% 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 body length here runs from 115 to 600 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
- Conservation status
- Least Concern
- Population trend
- Stable
The animal itself
- Colour on the back
- Brown
- Pattern on the back
- Uniform
- Pupil
- Round
- Venomous
- No
- Fangs
- None
- Longest recorded life
- 20.3years
Size
- Length nose to tail · greatest recorded
- 220mm8.75 in
- Shell length, front to back · greatest recorded
- 191mm7.5 in
- Largest female · shell length
- 191mm7.5 in
- Largest male · shell length
- 102mm4 in
- Body mass · greatestcomputed
- 1435g3.2 lb
- Body mass · a typical adult
- 415.7g14.7 oz
- Body mass at hatching
- 10.6g0.37 oz
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
largely converted from length by allometry in the source
AnAge rates this record "acceptable"
How it lives
- Diet
- Carnivorous
- How it hunts
- Active foraging
- Active
- Cathemeral
- Where it lives
- Aquatic
- Habitat
- Forest, Wetlands
- Region
- Nearctic
Invertebrates
Breeding
- Reproduction
- Oviparous
- Sex decided by
- Temperature
- Average clutch
- 5.75eggs
- Clutches in a year
- 2per year
- Egg length
- 37.03mm1.5 in
- Egg width
- 23.78mm0.9 in
- Age at first breeding · female
- 3105days
Naming and history
- Subspecies
- Graptemys nigrinoda nigrinoda CAGLE 1954 Graptemys nigrinoda delticola FOLKERTS & MOUNT 1969
- Described by
- Cagle
- Moved to another genus · since it was first described
- No
- Described in
- 1954
Keeping one
3 ft 2 in × 19 in(96 × 48 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 5 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 7.5 in (191 mm), at 5 times it — how this is worked out.
No preferred body temperature has been recorded for Black-knobbed Sawback. Rather than repeat a number from a care sheet, this page leaves it out.
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.
126kJ per day
Worked out for an animal of 1,435 g, the heaviest recorded for Black-knobbed Sawback — 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
- — 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
- — Largest juvenile · shell length
- — Body mass · adult female, mean
- — Preferred body temperature · chosen in a laboratory gradient
- — Body temperature when active · measured in the wild
- — Eats arthropods
- — Eats vertebrates
- — Eats plant matter
- — How the young develop
- — Gestation or incubation
- — Smallest clutch recorded
- — Largest clutch recorded
- — 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
- — Mature from · youngest recorded
- — Mature by · oldest recorded
- — Size at maturity · smallest recorded
- — Size at maturity · largest recorded
- — Body temp in the wild · lowest mean recorded
- — Body temp in the wild · highest mean 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
- — Lowest it lives · above sea level
- — Highest 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). Graptemys nigrinoda. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/graptemys-nigrinoda
@misc{graptemys_nigrinoda_2026,
title = {Graptemys nigrinoda},
author = {{The Reptile & Amphibian Encyclopedia}},
year = {2026},
url = {https://www.allanglescreatures.com/species/graptemys-nigrinoda}
}Sources
- Oskyrko, O. et al. (2024). ReptTraits: a comprehensive dataset of ecological traits in reptiles. Scientific Data. Used under CC BY 4.0.
- AnAge, Human Ageing Genomic Resources (de Magalhães et al.), used under CC BY 3.0.
- 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.