A Little Background on Pit Vipers and Rattlesnakes
All five of the venomous species of snake living in Missouri are pit vipers. Pit vipers get their name from the heat-sensing “pit” organs these snakes use to detect body heat and locate their prey. These pits look like two large holes on the snake’s face, located between its eyes and nostrils. Pit vipers have large, broad heads with a triangular shape, and necks that are distinctly smaller than their heads. These snakes also have vertical or slit-shaped pupils that look somewhat like cat eyes. Pit vipers have large, hollow fangs that they use to inject venom into their prey. Three of the Missouri’s pit vipers are also rattlesnakes: the timber rattlesnake, the western pygmy rattlesnake, and the massasauga rattlesnake. Rattlesnakes have hollow, keratin rings on the ends of their tails that form their iconic rattles. This usually makes them easy to identify. However, many nonvenomous snakes can be mistaken for pit vipers. Some can stretch or widen their necks when they feel threatened, making them look more like a pit viper. Many nonvenomous snakes also vibrate their tails against leaf litter to mimic a rattlesnake. In addition, rattlesnakes often break their rattles from time to time, and it takes a while for them to reform. It is always wise to keep a healthy distance from any wild snake you are unsure of.
1. Timber Rattlesnake
The timber rattlesnake lives in scattered populations throughout all of Missouri. This snake prefers rocky or rugged areas with hills and ledges covered in forests and woodlands. Timber rattlesnakes are skillful climbers, scaling tall trees and bushes in search of prey. During the spring and fall, timber rattlesnakes often bask in the sun on bluffs and rock ledges that face the south. They also spend much of their time hiding under large rocks or fallen logs as they wait for prey animals to pass by, or when they are digesting a recent meal. When the weather is too hot for these snakes, they will only hunt at night, early in the morning, or in the evenings when it is cooler. These snakes eat a wide variety of small mammals, as well as birds on occasion.
Appearance and Behavior
Timber rattlesnakes have large bodies that can grow over 70 inches in length. On average, however, these snakes are between 36-60 inches long with large, heavy bodies. Timber rattlesnakes are grey, brown, tan, or yellow, with darker V-shaped bands along the length of their bodies. Their bodies end with a “velvet-black” tail and a large, straw-colored rattle. Most timber rattlesnakes in Missouri also have an additional orange or rust-colored stripe running down the middle of their backs. Their bellies are usually grey or tan with dark speckles sprinkled throughout. The they have keeled scales along their bodies, which means that they have texturized ridges on each scale, giving the snake a coarse exterior. The colors, patterns, and texture of timber rattlesnakes help them to blend in with their surrounding environment. This is a great adaption for this snake, as timber rattlesnakes prefer using their camouflage to avoid being seen. Sometimes a timber rattlesnake will wait to use its rattle, preferring to remain hidden as much as possible. However, if it feels threatened, a timber rattlesnake will coil up and vibrate its rattle loudly in warning, and possibly strike if it feels cornered or harassed. The venom of the timber rattlesnake is extremely dangerous and requires immediate medical attention. In Missouri, however, timber rattlesnakes are rarely encountered, and there have only been a few cases of bites from these snakes.
2. Western Pygmy Rattlesnake
The western pygmy rattlesnake lives in the extreme south of Missouri. These snakes live along the border of Arkansas, and in the eastern Ozarks and St. Francois Mountains. Pygmy rattlesnakes prefer areas near glades, forests, rocky hillsides, wooded areas and meadows. These snakes often seek shelter under shrubs, logs, rocks or brush piles. They also enjoy basking in the sun, typically in rocky south-facing areas, near brush or shrubs, or along the side of the road. In July and August when the weather is hot, western pygmy rattlesnakes are mostly active at night, sometimes crossing roads in the dark. However, these snakes are rarely encountered by humans.
Appearance and Behavior
Western pygmy rattlesnakes are one of the smallest rattlesnake species, measuring between 20-30 inches in length. These colorful snakes have thick bodies with keeled or ridged scales with a rough texture. These snakes are typically a brownish-grey or silver-grey color, with dark blotches and an orange stripe running down the middle of their backs, and smaller dark spots along the sides of their bodies. The western pygmy rattlesnake has a very slender tail with 6-8 dark crossbands before its tiny rattle. It has a creamy colored belly with dark irregular bars, and a black stripe running from each eye to the corner of its mouth. Juvenile pygmy rattlesnakes look similar to adults but have a yellow-tipped tail that they use to lure lizards and frogs closer to eat. Each western pygmy rattlesnake seems to have its own individual personality and unique behavior. For example, some pygmy rattlesnakes are calm and tend to remain motionless to avoid detection. Some snakes may instead try to slither away quietly to escape threats, while others will boldly stand their ground by coiling, rattling their tails, and striking at anything that comes near them. However, because of their small size, western pygmy rattlesnakes have very small rattles on the end of their tails. When these snakes vibrate their tails, the small rattle does not make a very loud sound. Many report that the rattle of a pygmy rattlesnake sounds like a buzzing grasshopper rather than a loud rattlesnake.
3. Massasauga Rattlesnake
Originally there were two types of massasauga rattlesnakes living in Missouri. The first, the eastern massasauga rattlesnake, once lived along the Mississippi River Floodplain, north of St. Louis. However, this snake has not been observed in Missouri for several decades. Nevertheless, state specialists ask that the public and visitor to Missouri keep an eye out for any sightings of this snake. If you happen to see a snake that you think might an eastern massasauga, safely take a picture of it and report it to the Missouri Department of Conservation. The eastern massasauga is also a federally threatened species. Missouri’s other massasauga is the prairie massasauga rattlesnake. This snake is a subspecies of the western massasauga rattlesnake. Prairie massasauga rattlesnakes still live in Missouri, but they have suffered extensive habitat loss and human persecution. Because of this, the prairie massasauga rattlesnake is listed as an endangered species in Missouri and a species of conservation concern. There are only a handful of prairie massasauga populations left in Missouri. They now mostly live in the northwestern corner and a few north-central regions of the state. This snake lives in wet prairies, bottomlands, lowlands by rivers and lakes, and marshes. Prairie massasaugas spend much of the day basking in the sun, often near ant mounds, crayfish burrows or matted vegetation. During the winter these snakes brumate, safely tucked away in ant mounds, crayfish burrows or mammal burrows.
Appearance and Behavior
Prairie massasauga rattlesnakes have stocky bodies that typically are only 18-30 inches long, with keeled or ridged scales. These snakes are generally grey or a greyish brown color, with black, grey or brown blotches running along their backs, and 2-3 rows of smaller spots along both sides of their bodies. Prairie massasauga rattlesnakes also have two dark stripes on either side of their heads, lined with white. Their tails have dark bands near the rattle. The belly of a prairie massasauga rattlesnake is grey with dark speckles. However, there are some massasaugas in north-central Missouri that have mostly black bellies instead. Prairie massasauga rattlesnakes are not typically aggressive. Generally, these will first try to blend in and remain still, or quietly slither away from threats. However, if a snake feels threatened, cornered or harassed, it can quickly become quite defensive and will strike if necessary. Both the eastern massasauga and the prairie massasauga are protected rattlesnakes in Missouri. It is illegal to injure, kill or take any of these snakes from the wild for any reason. If you happen to see a massasauga rattlesnake in Missouri, please take a picture and report it to the Missouri Department of Conservation.
