“What kinds of venomous snakes can you find in Idaho?”
This question is extremely common. Everyone wants to know if any dangerous snakes live near them and what they look like!
Believe it or not, you can find TWO types of venomous snakes in Idaho. But please don’t live in fear, thinking that you are going to be bitten. In general, snakes try to avoid any contact or interaction with people. As long as you leave them alone, you shouldn’t have any trouble!
Did you know that snakes are considered venomous, NOT poisonous? If you eat something that makes you sick, then it’s considered “poisonous.” If an animal, like a snake, delivers its toxins when it bites, then it’s considered “venomous.”
*If you come across any of these species, PLEASE DO NOT DISTURB! Venomous snakes are dangerous animals and should be left alone. The more you agitate them, the more likely you could get bitten. DO NOT RELY ON THIS ARTICLE to correctly identify a snake that has recently bitten you. If you have recently been bitten, GO DIRECTLY to the nearest hospital to get help and to determine if the snake is venomous.*
2 Venomous Snakes That Live in Idaho:
RELATED: The 4 Types of SNAKES Found in Idaho! (ID Guide)
#1. Prairie Rattlesnake
- Crotalus viridis
- Adults typically range between 3.3 and 5 feet in length.
- Coloration is highly variable and can be greenish-gray, olive green, greenish-brown, light brown, or yellow. All variations have dark blotches on the body that turn into rings near the tail.
- Broad triangular head, elliptical pupils, heat-sensing pits between the eyes and nostrils, and a tail rattle.
These venomous snakes can be found in eastern Idaho in open prairies, grasslands, semi-desert shrublands, and forested environments. They can even be found at elevations up to 9500 feet!
The Prairie Rattlesnake hibernates during the winter, often in communal dens. These dens are typically rock crevices, caves, or old mammal burrows. Individual snakes will return to the same den each winter and migrate up to seven miles to their hunting grounds in the spring.
When they feel threatened, these snakes will freeze, trying to use their camouflage to avoid detection. They may also quietly crawl away to cover. If approached, they may coil and rattle their tail as a warning before striking. Their potent venom has both hemotoxic and neurotoxic properties, and although rare, can be fatal to an adult human.
Prairie Rattlesnakes are listed on the ICUN Red List as a species of least concern. However, they are considered threatened and declining in parts of their range. They have faced pressure from habitat fragmentation and hunting.
#2. Western Rattlesnake
- Crotalus oreganus
- Adult size varies widely over their range, with the largest individuals being 6 feet in length.
- Two subspecies live in Idaho – Northern Pacific and Great Basin.
- Triangular head, heat-sensing pits between the eyes and nostrils, dark stripe with white borders that runs from the eye towards the jaw.
You can find two different subspecies of the Western Rattlesnake in Idaho, and they look completely different. The Northern Pacific variety is dark brown or black with lighter-edged blotches. Great Basin Rattlesnakes are typically pale yellow, light gray, or tan, with brown and blackish blotches.
This venomous species occupies a wide range of habitats in Idaho. They can be found in mountainous areas, woodlands, and grasslands. They also often occur in close proximity to humans.
These snakes may be active during the day or night and are often curled, waiting to ambush a variety of prey. They’ll feed on small mammals, birds, reptiles, and amphibians. They may also eat bird eggs, and young snakes often feed on insects.
Like other rattlesnakes, this species gives birth to live young. Healthy, sexually mature females can give birth to litters of up to 25 babies!
Do you need additional help identifying a venomous snake?
I recommend purchasing a Peterson Field Guide to the Reptiles and Amphibians of North America. These books have lots of helpful information, including pictures and range maps. View Cost - Amazon
Which of these venomous snakes have YOU seen in Idaho?
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