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What is the Genus: Crotalus (Rattlesnakes)

What is the Genus: Crotalus

Crotalus Overview

Crotalus is a genus of venomous pit vipers in the family Viperidae, known as rattlesnakes or rattlers. Currently, 32 to 45 species are recognized as being valid.

For this article, we will only be discussing the Crotalus genus that is found in the southwest. (Links to each state are at the bottom of the article to view the snake in each southwestern state.)

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What is the Genus Crotalus (Rattlesnakes)

Beware Rattlesnakes Sign does not encourage hikers to explore off trail



The generic name Crotalus is derived from the Greek word κρόταλον krótalοn, which means “rattle” or “castanet”, and refers to the rattle on the end of the tail, which makes this group (genera Crotalus and Sistrurus) so distinctive.

Subspecies of Crotalus

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Size and Body Description

In general, adult males are slightly larger than females.

Compared to most snakes, they are heavy-bodied and most forms in the Southwest are easily recognized by the characteristic rattle on the end of their tails


Members of the genus Crotalus range in size from only 20″ – 28″ (C. intermedius, C. pricei), to over 59″  (eastern and western diamondback rattlesnakes).


The genus Crotalus is ovoviviparous, giving birth to live young.


The genus Crotalus is found in the Americas from southern Canada to central Argentina.

Arizona Black Rattlesnake, Crotalus Oreganus Cerberus

Arizona Black Rattlesnake, Crotalus Oreganus Cerberus

Where Found

They live in a variety of habitats, including forests, grasslands, scrub brush, swamps, and deserts, and they are also capable swimmers.

How Long do Crotalus Live

A rattlesnake’s typical lifespan is 10 to 25 years. 

Crotalus Diet

Rattlesnakes eat their food whole and because of this and with rattlesnakes having a very slow metabolism, adult rattlesnakes eat at least once in two weeks and their young eat once a week. 

Snakes do not have the right kind of teeth to chew their food so they must eat their food whole. The jaws of snakes are not fused to the skull, so the lower jaw can separate from the upper jaw. This allows their mouths to open wider than their own bodies in order to swallow their prey whole.

They favor small rodents and lizards. Smaller species feed mainly on lizards, while larger species start by feeding on lizards as juveniles and then switch to preying mainly on mammals as adults.

Water Sources

Herpetologists suspect that many desert-dwelling reptiles—including rattlesnakes—collect and drink rainwater that pools on their dorsal surfaces.

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References Used

What is the Genus: Crotalus