Reptilia · Squamata
Crotalus pyrrhusCope, 1866
Southwestern Speckled Rattlesnake
Photograph by Trevor Van Loon, CC BY, via iNaturalist
An active by day or night, meat-eating snake from the Nearctic region, reaching 111 cm snout to vent.
Reptilia › Squamata › Viperidae › Crotalus
- Grows to
- 1106mm
- greatest recorded
- Eats
- Carnivorous
- Active
- Cathemeral
- Weighs up to
- 824.5g
- greatest
Longer than 87% of all vipers 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 180 to 2,233 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
25 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
- Venomous
- Yes
- Fangs
- At the front of the mouth
- Body temperature when active · measured in the wild
- 29.7°C85 °F
- Body temp in the wild · mean, when active
- 17.5–34.5°C64–94 °F
mean body temperature of active individuals in nature
body temperature of active animals in nature
Size
- Length snout to vent · greatest recorded
- 1106mm3 ft 8 in
- Body mass · greatestcomputed
- 824.5g1.8 lb
Meik et al. 2018
computed from length by a family-level allometric equation, not weighed
How it lives
- Diet
- Carnivorous
- Active
- Cathemeral
- Biome
- Deserts & Xeric Shrublands
- Region
- Nearctic
- Mainland or island
- Mainland
- Range size
- 245,578km²
mammals and lizards (Grismer and Grismer 2022)
(Moore 1978), "active during the day during the cooler months, but become active at night with the onset of high summer temperatures" (Grismer and Grismer 2022)
Breeding
- Reproduction
- Viviparous
Grismer and Grismer 2022
Naming and history
- Suborder
- Serpentes
- Infraorder
- Alethinophidia
- Subspecies
- No
- Described by
- Cope
- Moved to another genus · since it was first described
- Yes
- Described in
- 1866
- Type locality
- USA
Keeping one
Active animals measured in the wild averaged 85 °F (29.7 °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.
77kJ per day
Worked out for an animal of 824 g, the heaviest recorded for Southwestern Speckled 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
- — Length nose to tail · greatest recorded
- — 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 it hunts
- — Where it lives
- — How the young develop
- — Gestation or incubation
- — Average clutch
- — Smallest clutch recorded
- — Largest clutch recorded
- — Mean clutch · smallest reported
- — Mean clutch · largest reported
- — 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
- — Pupil
- — 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
- — Highest 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 pyrrhus. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/crotalus-pyrrhus
@misc{crotalus_pyrrhus_2026,
title = {Crotalus pyrrhus},
author = {{The Reptile & Amphibian Encyclopedia}},
year = {2026},
url = {https://www.allanglescreatures.com/species/crotalus-pyrrhus}
}Sources
- Meiri, S. (2024). SquamBase — a database of squamate (Reptilia: Squamata) traits. Global Ecology and Biogeography. Public domain (CC0).
- Catalogue of Life (dataset 3LR), used under CC BY.
- Oskyrko, O. et al. (2024). ReptTraits: a comprehensive dataset of ecological traits in reptiles. Scientific Data. Used under CC BY 4.0.