All Angles Creatures
Squamata · ColubridaeEntry 20,141 of 21,572
West Coast Garter Snake, Thamnophis validus

Reptilia · Squamata

Thamnophis validusKennicott, 1860

West Coast Garter Snake

Photograph by Wouter Beukema, CC BY, via iNaturalist

A water-living, nocturnal, meat-eating snake from the Nearctic region, reaching 110 cm nose to tail.

ReptiliaSquamataColubridaeThamnophis

Grows to
1096mm
greatest recorded
Eats
Carnivorous
Active
Nocturnal
Lives
Aquatic
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

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

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
Body temperature when active · measured in the wild
26.83°C80 °F

mean body temperature of active individuals in nature

Body temp in the wild · mean, when active
9–35°C48–95 °F

body temperature of active animals in nature

Size

Length nose to tail · greatest recorded
1096mm3 ft 7 in

snakes only in this source

Body mass · greatestcomputed
320.9g11.3 oz

computed from length by a family-level allometric equation, not weighed

How it lives

Dietcomputed
Carnivorous

no actual data but can be imputed as carnivorous like all snakes

How it hunts
Active foraging

Active (Hernandez-Salinas et al. 2023)

Active
Nocturnal

Feldman 2015

Where it lives
Aquatic

(Feldman 2015, Deepak et al. 2022), semi aquatic (Arrazola-Bohorquez and Palacios-Aguilar 2022)

Biome
Tropical & Subtropical Dry Broadleaf Forests
Region
Nearctic
Mainland or island
Mainland
Highest it lives · above sea level
1200m

0-1200 (Feldman 2015)

Range size
120,431km²

Breeding

Reproduction
Viviparous

Feldman et al. 2015

Eggs or young per clutch
32eggs

mean=32 (Feldman 2015)

Mean clutch
32eggs

Naming and history

Suborder
Serpentes
Infraorder
Alethinophidia
Subspecies
Thamnophis validus celaeno (COPE 1861) Thamnophis validus isabellae (CONANT 1953) Thamnophis validus thamnophisoides (CONANT 1961) Thamnophis validus validus (KENNICOTT 1860)
Described by
Kennicott
Moved to another genus · since it was first described
Yes
Described in
1860
Type locality
Mexico

Keeping one

3 ft 7 in × 21.5 in × 2 ft 8 in(110 × 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.

Spends time in water, so a water area is part of the enclosure rather than a dish.

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 (1096 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 80 °F (26.8 °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 321 g, the heaviest recorded for West Coast 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 · snout to vent
  • Hatchling length · nose to tail
  • Largest juvenile · snout to vent
  • Largest juvenile · shell length
  • Egg length
  • Egg width
  • Body mass · a typical adult
  • Body mass · adult female, mean
  • Body mass at hatching
  • Longest recorded life
  • Preferred body temperature · chosen in a laboratory gradient
  • Eats arthropods
  • Eats vertebrates
  • Eats plant matter
  • How the young develop
  • Gestation or incubation
  • Average clutch
  • Clutches in a year
  • 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
  • Colour on the back
  • Pattern on the back
  • Sex decided by
  • Red List criteria
  • Active season · shortest recorded
  • Active season · longest recorded
  • Density · lowest recorded
  • Density · highest recorded
  • Home range · largest recorded
  • Habitat
  • 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 validus. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/thamnophis-validus

@misc{thamnophis_validus_2026,
  title  = {Thamnophis validus},
  author = {{The Reptile & Amphibian Encyclopedia}},
  year   = {2026},
  url    = {https://www.allanglescreatures.com/species/thamnophis-validus}
}

Sources

  1. Meiri, S. (2024). SquamBase — a database of squamate (Reptilia: Squamata) traits. Global Ecology and Biogeography. Public domain (CC0).
  2. Catalogue of Life (dataset 3LR), used under CC BY.
  3. Oskyrko, O. et al. (2024). ReptTraits: a comprehensive dataset of ecological traits in reptiles. Scientific Data. Used under CC BY 4.0.