Rattlesnakes in Idaho
A rattlesnake’s most distinct feature is the iconic rattle at the end of the snake’s tail. When a rattlesnake feels threatened, it will often coil up its body and vibrate the end of its tail, which causes the rattle to make a loud warning sound. The snake’s rattle is made of segments of keratin that build up each time the snake sheds. However, contrary to popular belief, you cannot tell the age of a rattlesnake by how many segments are on its rattle. Rattlesnakes shed 2-3 times a year, and sometimes the rattle can even break off. It is always important to be careful even if you do not initially see a rattle on the snake’s tail. Rattlesnakes are also venomous pit vipers. They have two large venom glands that give these snakes a heart-shaped or triangular-shaped head. Rattlesnakes also have heat-sensing “pits” on their faces. These pits look almost like an extra pair of nostrils, between the snake’s real nostrils and its eyes. Heat-sensing pits allow these snakes to detect infrared heat and map out the location of potential prey. Although they are big and venomous, and it is important to give rattlesnakes a wide berth, rattlesnakes in Idaho are generally not aggressive. In fact, many snakes will freeze and stay quiet if they see a human. Instead of acting defensively, rattlesnakes will try to blend into their surroundings. There is a good chance you will walk right past a rattlesnake and never know it! That is why it is so important to always look carefully where you step outside, and where you place your hands or sit down. By taking just a moment to look around, you can hopefully avoid accidentally disturbing a rattlesnake.
1. Prairie Rattlesnake (or Western Rattlesnake)
The Prairie Rattlesnake (also known as the Western Rattlesnake) lives in east-central Idaho, as well as a very small section near the northeastern corner of the state. Its range covers much of the midwestern United States, as well as northern Mexico and southwestern Canada. Prairie rattlesnakes are generally more common in drier areas with rocky outcroppings and sagebrush, but they can also live in forests, shrublands, and grasslands. Although you could potentially encounter a prairie rattlesnake any time of the year, you most likely will not see these snakes during cold winter months. This is because prairie rattlesnakes brumate (similar to hibernation) in caves, burrows, or rocky crevices. Many snakes will even travel several miles from their usual home to find a suitable place for their winter brumation.
Appearance and Behavior
Prairie rattlesnakes grow between 36-60 inches in length with fairly thick bodies. In Idaho these snakes are typically light brown or tan in color, with several darker brown blotches running along their backs. These blotches are often outlined by thin black and white lines, and two white stripes surrounding a dark brown one runs behind the snakes’ eyes. The scales along their bodies are heavily keeled, with rough ridges in the middle of each scale. This appearance is similar to the nonvenomous Gopher Snake. However, gopher snakes have more slender bodies without a rattle on the end of their tails. In addition, gopher snakes have rounded, bullet-shaped heads instead of the large triangular head of a rattlesnake. If you come across a snake but you are not sure which type it is, give the snake a wide berth and leave it alone. Prairie rattlesnakes are ambush hunters that like to hide on a slightly elevated spot while they wait for prey animals to pass by. These snakes commonly coil their bodies on rocks, tree stumps, and even in bushes or trees while they wait for their prey to come within striking distance. Prairie rattlesnakes primarily eat small mammals like mice, rats, and squirrels. Juvenile snakes typically eat smaller animals like other snakes and reptiles. The venom of a prairie rattlesnake is a complex mix of hemotoxins and neurotoxins.
2. Northern Pacific Rattlesnake (previously known as the Western Rattlesnake)
This can be a bit confusing, but the Northern Pacific Rattlesnake is also commonly called the “Western Rattlesnake”. This is because traditionally the northern pacific rattlesnake was a subspecies of western rattlesnake, but it has recently been listed as its own separate species. The Northern Pacific Rattlesnake lives in the southern 2/3 of Idaho, particularly in the west-central regions of the state. Its range covers much of the western United States, as well as Canada’s British Columbia and northwestern Mexico. Northern pacific rattlesnakes live in a wide variety of different habitats, although they tend to prefer somewhat drier areas. These snakes commonly live in grasslands, prairies, brush, rock ledges, caves, forests, woodlands, and along streams. Northern pacific rattlesnakes grow around 36-40 inches in length, although the largest snake recorded was 64 inches long!
Appearance and Behavior
These snakes are brown, grey, yellowish, or even black, with large dark blotches running down the middle of their backs. The space between each blotch is smaller than the blotches themselves, which are outlined with very thin cream or white borders. There are also smaller dark blotches along the sides of the snake’s body, and several rings near the end of the snake’s tail. A lightly bordered, dark brown stripe runs from each eye to the back of the snake’s jaw. The appearance of northern pacific rattlesnakes changes over the course of their lives. Younger snakes are usually lighter in color with very distinct blotches and patterns. As they age, however, their colors darken, and their patterns begin to fade into the background. Northern pacific rattlesnakes are also ambush hunters that patiently lie in wait until small prey animals come close enough to strike. These snakes eat small mammals like squirrels, mice, rats, and rabbits, as well as birds, other snakes, amphibians, and small reptiles. Their venom is a mix of hemotoxins and neurotoxins and can cause swelling, headaches, necrosis, internal bleeding, and various cardiovascular problems.
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