Rattlesnakes are present in Missouri. Three distinct species can be found across different regions of the state.
Rattlesnake Species Found in Missouri
The Timber Rattlesnake (Crotalus horridus) is Missouri’s largest venomous snake, typically 30-60 inches long. Its coloration varies from yellowish-brown to gray or black, featuring dark crossbands. A rust-colored stripe often runs down its back, and its tail is frequently described as “velvet-tailed” due to its dark appearance before the rattle.
The Western Pygmy Rattlesnake (Sistrurus miliarius streckeri) is a smaller species, usually 15-20 inches long, though some can reach 33 inches. It has a brownish-gray body with small, dark blotches in rows. A narrow orange-brown stripe may be present along its back, and a distinct black stripe extends from its eye to its mouth. Its notably small rattle produces a faint buzz, similar to a grasshopper.
The Massasauga rattlesnake (Prairie Massasauga, Sistrurus tergeminus tergeminus) is a medium-sized snake, typically 18-30 inches. It generally has a gray to light brown body with dark blotches along its back and smaller side spots. It possesses a broad, triangular head and a rattle. The Eastern Massasauga (Sistrurus catenatus) historically occurred in Missouri but is now considered extirpated.
Typical Habitats and Distribution
Timber Rattlesnakes are widespread across Missouri, inhabiting various environments. They are found in lowland thickets, river and floodplain areas, agricultural lands, and both deciduous and coniferous forests. These snakes often prefer mature forests with rocky outcroppings, particularly south-facing hillsides with ledges and bluffs.
Western Pygmy Rattlesnakes have a more restricted distribution within Missouri, primarily in the extreme southern counties bordering Arkansas and the eastern Ozarks. Their preferred habitats include glades, second-growth forests near rock ledges, and transitional areas between forests and open lands. They often seek shelter under rocks, logs, or brush piles.
Massasauga rattlesnakes are limited to north-central and northwestern Missouri. They are typically found in wet habitats such as bottomland prairies, wet prairies, shrub swamps, and low-lying areas along rivers and lakes. They may also use drier adjacent upland areas during certain times of the year.
Identifying Rattlesnakes and Staying Safe
Rattlesnakes have several common features. All Missouri rattlesnakes, as pit vipers, possess a triangular head noticeably wider than their neck. They also have heat-sensing pits between their eyes and nostrils. Another characteristic is their elliptical, or cat-like, pupils. A rattle at the end of their tail is the most distinct identifier, though a snake may not always rattle or its rattle can be damaged.
When in rattlesnake habitats, practice safety measures. Wear protective footwear, such as boots, and watch where you step and place your hands. Avoid tall grass, heavy underbrush, and rock or log piles where snakes may hide. If you encounter a snake, give it space and avoid provoking it. Snakes generally prefer to avoid human interaction and will retreat if given the opportunity.
In case of a rattlesnake bite, seek immediate medical attention, remaining calm and minimizing physical activity to help prevent the potential spread of venom. Remove any rings, watches, or restrictive clothing from the affected limb to account for possible swelling. Keep the bitten area below the heart if possible. Do not apply ice, a tourniquet, cut the wound, or suck out venom, as these actions can cause further harm. Transport to the nearest medical facility quickly.