Reptilia · Squamata
Thamnophis proximusSay, 1823
Western Ribbonsnake
Photograph by Adam Cohen, CC BY, via iNaturalist
A day-active, meat-eating snake from the Nearctic region, reaching 123 cm nose to tail.
Also called Western Ribbon Snake.
Reptilia › Squamata › Colubridae › Thamnophis
- Grows to
- 1230mm
- greatest recorded
- Eats
- Carnivorous
- Active
- Diurnal
- Lives up to
- 3.6years
Longer than 82% of all colubrid snakes 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 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
43 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
- 2005
- Population trend
- Stable
The animal itself
- Limbs
- None
- Pupil
- Round
- Venomous
- Yes
- Fangs
- At the back of the mouth
- Longest recorded life
- 3.6years
- Body temperature when active · measured in the wild
- 23.37°C74 °F
- Body temp in the wild · mean, when active
- 9–35°C48–95 °F
mean body temperature of active individuals in nature
body temperature of active animals in nature
Size
- Length snout to vent · greatest recorded
- 635.3mm2 ft 1 in
- Length nose to tail · greatest recorded
- 1230mm4 ft
- Largest male · snout to vent
- 420mm16.5 in
- Hatchling length · nose to tail
- 175mm7 in
- Body mass · greatestcomputed
- 453g16 oz
- Body mass · adult female, meanmeasured
- 62.3g2.2 oz
- Body mass at hatchingmeasured
- 2.24g0.08 oz
snakes only in this source
snout-vent length; the source column mixes this with straight carapace length
computed from length by a family-level allometric equation, not weighed
How it lives
- Diet
- Carnivorous
- How it hunts
- Active foraging
- Active
- Diurnal
- Where it lives
- Semi-aquatic
- Habitat
- Forest, Grassland, Savanna, Shrubland, Wetlands
- Biome
- Temperate Grasslands, Savannas & Shrublands
- Region
- Nearctic
- Mainland or island
- Mainland
- Highest it lives · above sea level
- 2440m
- Range size
- 2,197,434km²
- Density
- 16–61per hectare
frogs and fishes (Zeas and Alvarado 2015, Sheldon 2022, Phillips et al. 2022)
Active (Leenders 2019)
Leenders 2019, Hu et al. 2020
(Leenders 2019, Hu et al. 2020, Deepak et al. 2022), also climbs (Phillips et al. 2022)
NSL-1750 (Leenders 2019), 0-2438 (O'Shea 2018), max 2400 (Zeas and Alvarado 2015)
Breeding
- Reproduction
- Viviparous
- Average clutch
- 19eggs
- Eggs or young per clutch
- 4–36eggs
- Mean clutch
- 8.4–19eggs
- Clutches in a year
- 1per year
- Clutches a year
- 0.81–1per year
- First breeds at
- 24–36months
Feldman et al. 2015
mean 19 (Meiri et al. 2019), 8-12 (O'Shea 2018), 10-12 (Zeas and Alvarado 2015), 4-36 (Sheldon 2022), 10-15 (Phillips et al. 2022), Rossman et al. 1996 (means 8.4-12.9)
Naming and history
- Suborder
- Serpentes
- Infraorder
- Alethinophidia
- Subspecies
- Thamnophis proximus alpinus ROSSMAN 1963 Thamnophis proximus diabolicus ROSSMAN 1963 Thamnophis proximus orarius ROSSMAN 1963 Thamnophis proximus proximus (SAY 1823) Thamnophis proximus rubrilineatus ROSSMAN 1963 Thamnophis proximus rutiloris (COPE 1885)
- Described by
- Say
- Moved to another genus · since it was first described
- Yes
- Described in
- 1823
- Type locality
- USA
Keeping one
4 ft × 2 ft × 3 ft(123 × 62 × 92 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 4 ft (1230 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 74 °F (23.4 °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.
45kJ per day
Worked out for an animal of 453 g, the heaviest recorded for Western Ribbonsnake — 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 · 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 female · shell length
- — Largest male · shell length
- — Hatchling length · snout to vent
- — Largest juvenile · snout to vent
- — Largest juvenile · shell length
- — Egg length
- — Egg width
- — Body mass · a typical adult
- — Preferred body temperature · chosen in a laboratory gradient
- — Eats arthropods
- — Eats vertebrates
- — Eats plant matter
- — How the young develop
- — Gestation or incubation
- — 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 proximus. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/thamnophis-proximus
@misc{thamnophis_proximus_2026,
title = {Thamnophis proximus},
author = {{The Reptile & Amphibian Encyclopedia}},
year = {2026},
url = {https://www.allanglescreatures.com/species/thamnophis-proximus}
}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.