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Squamata · ViperidaeEntry 5,377 of 21,572
Timber rattlesnake, Crotalus horridus

Reptilia · Squamata

Crotalus horridusLinnaeus, 1758

Timber rattlesnake

Photograph placed in the public domain, CC0, via iNaturalist

A ground-dwelling, day-active, meat-eating snake from the Nearctic region, reaching 189 cm nose to tail.

Also called cane-brake rattlesnake (atricaudatus).

ReptiliaSquamataViperidaeCrotalus

Grows to
1892mm
greatest recorded
Eats
Carnivorous
Active
Diurnal
Lives up to
52years
Body length across Viperidae

Longer than 94% of all vipers anyone has measured.

94% of 362 species are smaller6% larger
280 mmthe whole family, smallest to largest3,900 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 280 to 3,900 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
2007
Population trend
Decreasing

The animal itself

Limbs
None
Venomous
Yes
Fangs
At the front of the mouth
Longest recorded life
52years

Stark et al. 2020

Body temperature when active · measured in the wild
25.9°C79 °F

mean body temperature of active individuals in nature

Body temp in the wild · mean, when active
25.9°C

body temperature of active animals in nature

Size

Length snout to vent · greatest recorded
1680mm5 ft 6 in

1892 mm total length (Feldman et al. 2016), Borgardt 2021: 168 cm SVL, 183 cm total length, excluding the rattle, 87 g (the Steinhardt Museum of Natural History), neomates 25-35 cm TL (Phillips et al. 2022)

Length nose to tail · greatest recorded
1892mm6 ft 2 in

snakes only in this source

Hatchling length · nose to tail
300mm12 in
Body mass · greatestcomputed
2501.5g5.5 lb

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

Body mass · a typical adult
1000g2.2 lb

AnAge rates this record "acceptable"

Body mass at hatchingmeasured
20g0.71 oz

How it lives

Diet
Carnivorous

rodents and rabbits (Sheldon 2022)

How it hunts
Sit and wait

Sit (Guyer et al. 2019, Camper 2019, Glaudas et al. 2019, O'Shea 2018, Maag and Clark 2022)

Active
Diurnal

Stark et al. 2018, Hu et al. 2020, Phillips et al. 2022

Where it lives
Terrestrial

Scharf et al. 2015, Hu et al. 2020

Habitat
Forest, Rocky, Wetlands
Biome
Temperate Broadleaf & Mixed Forests
Active season · months of the year
6–7months
Region
Nearctic
Mainland or island
Mainland
Highest it lives · above sea level
2000m

0-2000 (O'Shea 2018)

Range size
2,049,510km²

Breeding

Reproduction
Viviparous

Feldman et al. 2015, Meiri et al. 2019

Gestation or incubation
135days
Average clutch
10.4eggs
Eggs or young per clutch
1–20eggs

1-20 mean=10 (Camper 2019), mean=12 (Guyer et al. 2019), 3-16 (O'Shea 2011), 4-20 (Beane et al. 2010), 3-19 means: 6-10 (Murphy et al. 2003), 4-14 (O'Shea 2018), 3-18 (Sheldon 2022), 6-10 (Phillips et al. 2022)

Mean clutch
6–12eggs
Clutches in a year
0.5per year
Clutches a year
0.25–0.5per year
First breeds at
48–66months
Age at first breeding · female
2555days

Naming and history

Suborder
Serpentes
Infraorder
Alethinophidia
Subspecies
No
Described by
Linnaeus
Moved to another genus · since it was first described
No
Described in
1758
Type locality
America

Keeping one

6 ft 2 in × 3 ft 1 in × 4 ft 8 in(189 × 95 × 142 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 6 ft 2 in (1892 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 79 °F (25.9 °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.

206kJ per day

Worked out for an animal of 2,501 g, the heaviest recorded for Timber rattlesnake — 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 male · 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 · adult female, mean
  • Preferred body temperature · chosen in a laboratory gradient
  • Eats arthropods
  • Eats vertebrates
  • Eats plant matter
  • How the young develop
  • 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
  • Colour on the back
  • Pattern on the back
  • Pupil
  • Sex decided by
  • Red List criteria
  • Density · lowest recorded
  • Density · highest recorded
  • Home range · largest recorded
  • Active in
  • Lowest it lives · above sea level

Others in Viperidae

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). Crotalus horridus. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/crotalus-horridus

@misc{crotalus_horridus_2026,
  title  = {Crotalus horridus},
  author = {{The Reptile & Amphibian Encyclopedia}},
  year   = {2026},
  url    = {https://www.allanglescreatures.com/species/crotalus-horridus}
}

Sources

  1. Meiri, S. (2024). SquamBase — a database of squamate (Reptilia: Squamata) traits. Global Ecology and Biogeography. Public domain (CC0).
  2. AnAge, Human Ageing Genomic Resources (de Magalhães et al.), used under CC BY 3.0.
  3. Oskyrko, O. et al. (2024). ReptTraits: a comprehensive dataset of ecological traits in reptiles. Scientific Data. Used under CC BY 4.0.
  4. Catalogue of Life (dataset 3LR), used under CC BY.