Western (Prairie) Rattlesnake
Category: Birding at the Chico

The more common of the two poisonous Colorado rattlesnakes, the western or prairie rattlesnake (Crotalus viridus) is found across the Great Plains.  The other poisonous Colorado snake is the small and very local Massasauga (Sistrurus catenatus). Seven to eight thousand people are bitten by rattlesnakes each year but death from a snake bite in the U.S. is usually about five persons per year. Snake bites in humans are mostly from two rattlesnake species not occurring in Colorado, eastern diamondback and western diamondback.  However, on October 7 of this year a 31-year-old man was bitten on the ankle near Golden, Colorado and he died from the venomous bite. Rattlesnake venom contains both a hemotoxin (affects the blood) and a neurotoxin (affects the nervous system) and the amount injected is usually 20% to 55% of a snake’s stored venom; but a rattlesnake can give a dry bite up to 20% of the time.

Prairie rattlesnakes are viviparous meaning they give to birth to live young, usually in late August into September so it is not uncommon to see young-of-the-year on dirt roads during this time period like the one in this photograph. In October, or sometimes into November, prairie rattlesnakes move to burrows to overwinter, often with over one hundred other snakes including other snake species. If available, rattlesnakes often use prairie-dog burrows in which to spend winter months.

The number of rattles on a rattlesnake shouldn’t be used to age a rattlesnake as they produce a new one every time they shed their skin which is usually at least twice a year if the food source is abundant. In Colorado, prairie rattlesnakes eat a lot of field mice and rodents as large as a small prairie dog and small prairie cottontails, but lizards, voles, and shrews are also commonly consumed.

Rattlesnake meat can be consumed by man, but on the Chico prairie rattlesnakes are hunted by raports like this Red-tailed Hawk whose bare legs are usually not, but sometimes susceptible to a rattlesnake bite. Woodrats, found in draws with cholla cactus, are immune from rattlesnake venom and they will bite back when attacked by a rattlesnake. Although I don't always follow my own advice, it is best to leave rattlesnakes to the hawks.

Posted by Bill M. on 10/17/2017
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