Thamnophis elegansBaird & Girard, 1853

Western Terrestrial Garter Snake

Photograph placed in the public domain, CC0, via iNaturalist

A day-active, meat-eating snake from the Nearctic region, reaching 109 cm nose to tail.

Reptilia › Squamata › Colubridae › Thamnophis

Grows to: 1090mm; greatest recorded
Eats: Carnivorous
Active: Diurnal
Lives up to: 17.8years

Body length across Colubridae

Longer than 75% of all colubrid snakes anyone has measured.

75% of 2,008 species are smaller25% larger

98 mmthe whole family, smallest to largest3,800 mm

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 98 to 3,800 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

40 sourced facts, each taken from a named scientific dataset. How to read these.

Cited from a dataset unless a row is marked otherwise.

Two of these figures disagree

Body mass (a typical adult) is given as 400, and Body mass (greatest) as 315.6 — but a typical adult cannot outweigh the heaviest one ever recorded. They come from different sources and both are shown exactly as those sources give them.

Standing in the world

Still living: Extant
Conservation status: Least Concern
Status assessed · the year the Red List last looked: 2007
Population trend: Stable

The animal itself

Limbs: None
Pupil: Round
Venomous: Yes
Fangs: At the back of the mouth
Longest recorded life: 17.8years
Body temperature when active · measured in the wild: 25.7°C78 °F
Body temp in the wild · mean, when active: 25.7°C

Size

Length nose to tail · greatest recorded: 1090mm3 ft 7 in
Hatchling length · snout to vent: 176mm7 in
Body mass at hatchingmeasured: 1.78g0.06 oz
Body mass · greatestcomputeddisputed: 315.6g11.1 oz
Body mass · a typical adultdisputed: 400g14.1 oz

How it lives

Dietcomputed: Carnivorous
How it hunts: Active foraging
Active: Diurnal
Where it lives: Semi-aquatic
Habitat: Forest, Grassland, Savanna, Shrubland, Wetlands
Biome: Deserts & Xeric Shrublands
Region: Nearctic
Mainland or island: Mainland
Highest it lives · above sea level: 3990m
Range size: 2,840,855km²
Density: 2.8per hectare

Breeding

Reproduction: Viviparous
Average clutch: 8.7eggs
Eggs or young per clutch: 4–27eggs
Mean clutch: 6.3–10.6eggs
Clutches a year: 1per year
First breeds at: 24months

Naming and history

Suborder: Serpentes
Infraorder: Alethinophidia
Subspecies: Thamnophis elegans elegans (BAIRD & GIRARD 1853) Thamnophis elegans vagrans (BAIRD & GIRARD 1853) Thamnophis elegans hueyi VAN DENBURGH & SLEVIN 1923 Thamnophis elegans terrestris FOX 1951
Described by: Baird & Girard
Moved to another genus · since it was first described: Yes
Described in: 1853
Type locality: USA

Keeping one

3 ft 7 in × 21.5 in × 2 ft 8 in(109 × 55 × 82 cm)

Minimum length × width × height, for one animal. Bigger is always better.

The standard sizes snakes as a fraction of total length: 1 × 0.5 × 0.75.

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 total length of 3 ft 7 in (1090 mm), at 1 × 0.5 × 0.75 times it, following the German federal welfare standard — how this is worked out.

Active animals measured in the wild averaged 78 °F (25.7 °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 between the same width as the widest part of the snake's body and about 1.5 times that width.

Widely used across snake husbandry references. An alternative formulation gives prey at 10-15% of the snake's body mass. This is established practice, not a measurement.

33kJ per day

Worked out for an animal of 316 g, the heaviest recorded for Western Terrestrial Garter Snake — 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 · 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
— Largest female · shell length
— Largest male · shell length
— 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
— Clutches in a year
— 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
— Sex decided by
— Red List criteria
— Active season · shortest recorded
— Active season · longest recorded
— Home range · largest recorded
— Active in
— Lowest it lives · above sea level

Others in Colubridae

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). Thamnophis elegans. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/thamnophis-elegans

@misc{thamnophis_elegans_2026,
  title  = {Thamnophis elegans},
  author = {{The Reptile & Amphibian Encyclopedia}},
  year   = {2026},
  url    = {https://www.allanglescreatures.com/species/thamnophis-elegans}
}

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.