Timber Rattlesnake

Image of a timber rattlesnake
Safety Concerns
Scientific Name
Crotalus horridus
Viperidae (venomous snakes) in the order Squamata (lizards and snakes)

The timber rattlesnake is Missouri's largest venomous snake. Generally tan or yellowish tan, the timber rattlesnake has markings along the back that are dark brown and change from blotches on the neck to bands near the tail. Often, a dark line extends from the eye along the angle of the jaw, and there is a rust-colored stripe down the back. It has a large rattle at the end of its tail. Like all venomous snakes in Missouri, rattlesnakes have a hole between the nostril and the eye, and the pupils, in daylight, are vertical, like a cat’s.

This snake, like many others, uses camouflage to avoid being seen; however, it will bite if harassed. It is dangerously venomous, and medical attention must be sought immediately if someone is bitten. There are only a few cases of rattlesnake bites in Missouri. Rattlesnakes typically vibrate their tails, causing a sharp buzzing sound, when alarmed. Do not rely on a rattle sound for identification, though; remember that snakes' tails are occasionally injured or cut off, and that a surprised snake may not have time to sound its rattle.

Similar species: The timber rattlesnake, found statewide, is our most widespread rattlesnake. Missouri has three other rattlesnakes known from within its borders, each with limited distributions. The western pygmy rattlesnake (Sistrurus miliarius streckeri), which does not exceed 20 inches in length, lives in counties bordering Arkansas and in the eastern Missouri Ozarks. The prairie massasauga (S. tergeminus tergeminus) is limited to the northwestern corner of the state and some north-central counties; it is state endangered. The eastern massasauga (S. catenatus) occurred along the Mississippi floodplain north from St. Louis; it has apparently been extirpated from our state.


Length: 36 to 60 inches (about 3–5 feet).

Where To Find
Timber Rattlesnake Distribution Map

Formerly statewide, but now eliminated from a number of counties.

This rattlesnake lives on rocky, wooded hillsides and mature forests. In Missouri, it tends to congregate in selected south-facing rocky areas where it overwinters. Due to the rough country where this species normally occurs, and the fact that it is mostly nocturnal during the summer, few Missourians encounter this species.

Timber rattlesnakes eat a variety of rodents and also small rabbits. They use their venom so that they can take their prey without a struggle. A secondary use for the venom is for self-defense.

Habitat loss and persecution have caused a continuous decline of this species in our state.

Life Cycle

Active from April into early October. They bask on sunny rocks in spring and autumn. In summer they are mostly nocturnal. Courtship and mating occurs soon after they emerge from overwintering dens, or in late summer. Females produce a litter of young every other year, beginning in their fourth or fifth year of life. Birthing is in late summer into early October. Litters average about 8 or 9 young. Newborns have one rattle segment. Each time they shed their skin, a new segment is created.

Venomous snakes play an important role in many human religions. Also, the fear and curiosity that venomous animals inspire often lead us to look more closely at the natural world as a whole. Many naturalists, professional and amateur, got their start by learning about such awe-inspiring creatures.

Many of the animals that rattlesnakes eat (such as rodents and rabbits) are problematic for human interests such as food and grain storage, and agriculture. Many of us do not feel love for snakes, but we must appreciate the work they do that helps our economic interests.

As predators of rodents and small rabbits, rattlesnakes serve a vital role in controlling the populations of those prolific breeders. Yet they, too, fall prey to other predators such as hawks, owls, minks, skunks, and herons. Their young are especially vulnerable to predation. The buzzing or rattling sound is a warning to potential predators or others who might otherwise molest this snake; this communication gives the snake and a potential enemy a chance to de-escalate a confrontation, so that biting need not occur.

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Similar Species
About Reptiles and Amphibians in Missouri
Missouri’s herptiles comprise 43 amphibians and 75 reptiles. Amphibians, including salamanders, toads, and frogs, are vertebrate animals that spend at least part of their life cycle in water. They usually have moist skin, lack scales or claws, and are ectothermal (cold-blooded), so they do not produce their own body heat the way birds and mammals do. Reptiles, including turtles, lizards, and snakes, are also vertebrates, and most are ectothermal, but unlike amphibians, reptiles have dry skin with scales, the ones with legs have claws, and they do not have to live part of their lives in water.