|Geographical Range||Eastern United States|
|Habitat||Heavily wooded upland forests with rocky outcrops|
|Scientific Name||Crotalus horridus|
|Conservation Status||Not listed by IUCN|
Deadly -- but Shy
The venom of timber rattlesnakes is so potent that it can kill a human. In reality, however, there are few reported cases of people being bitten by timber rattlesnakes. Why? For one thing, these reptiles are shy -- they won't bite unless they feel threatened. In fact, they'll warn you to stay away by shaking their rattle! Besides this, most people don't spend a lot of time in hilly wooded areas, where timber rattlesnakes live. And if people do go for a summer hike in the woods, they're unlikely to encounter the snakes, which take refuge in leaf litter or under rocks and logs on hot summer days.
From Head to Rattle
Timber rattlesnakes are the largest venomous snake found in Missouri, ranging from three to five feet long - not including the rattle!
These snakes are members of the viper family. Like other North American vipers, they have a broad, flat, triangular-shaped head. In timber rattlesnakes, the head is colored yellow, tan, or gray, and usually has a dark line running from each eye to the jaw.
Their main body color may be yellow, tan, brown or gray. Dark markings appear in bands around the body; they're rounded toward the head and become more v-shaped toward the tail. There's often a brown stripe along the back. The tail is black and has a prominent rattle at the end.
Their coloring helps timber rattlesnakes blend in with their surroundings -- bushes, branches, and leaves. Their natural camouflage makes them nearly "invisible" as they lay in wait for prey.
On the Menu
So what do timber rattlesnakes like to eat? At the top of the menu are small birds and mammals, including rodents, moles, small rabbits -- even bats! When it comes to hunting, timber rattlesnakes have a secret weapon. Like all pitvipers, they have special heat-sensitive pits located on each side of the head. These sensors help them hone in on birds and mammals.
Timber rattlesnakes round out their menu with lizards, small snakes, frogs, and insects. Sometimes they even eat carrion (dead meat).
From Sunbathing to Hibernating
Like all reptiles, timber rattlesnakes have to regulate their own body temperature because they are ectotherms (what used to be called "cold-blooded"). When the weather is moderate (spring and fall), the snakes are active during the day. During these times, they spend a lot of time basking in the sun on south-facing rock ledges and bluffs.
Sunbathing is great for keeping warm when the weather is moderate, but it's not a good idea when the weather gets hot. During the hottest summer weather, the snakes avoid the midday sunshine, becoming more active during the cooler nighttime hours.
When winter weather hits, timber rattlesnakes face a new challenge: avoiding the cold. They do this by brumating in protected places. (This means they are in a hibernation-like state, but may wake up periodically.) In some areas, many snakes (up to 100!) gather together in winter dens. Other snakes brumate alone or in small groups in mammal burrows, rock crevices, or old tree stumps. If the weather warms up and the sun is out, the snakes may emerge from their winter dens to bask for short periods of time.
Among timber rattlesnakes, courtship and mating occur either in the spring or in late summer. A male timber rattlesnake courts a willing female with a special three-step "dance." First he moves alongside and on top of the female. Then he starts rubbing his head and body against hers with jerky movements. Finally, he curls his tail under the female's, and mating takes place.
The female gives birth to live young in late summer or early fall. A litter may have anywhere from five to 14 snakelings, with eight being the average. Newborns are about 10 to 13 inches long, and are somewhat lighter in color than adults.
Babies are born with a single tiny rattle segment (called a button) on their tail. Each time the skin is shed, a new segment is added to the base of the tail. You'd think this means the rattle will grow longer and longer throughout a snake's lifetime. But no! As the rattle becomes longer, the end pieces become weak and break off.
Female timber rattlesnakes, and some other pit vipers, keep close watch over their young, a trait that's rather unusual among snakes. Female timber rattlers even lay scent trails to help their offspring find winter dens.
Young timber rattlesnakes fall victim to a variety of natural predators, including hawks, bobcats, coyotes, foxes, skunks and king snakes.
Adults, on the other hand, have few enemies -- except people. Many people hunt timber rattlesnakes for their meat, rattles, or skins (used to make products like wallets and belts). Some people kill timber rattlesnakes because they mistakenly believe they're dangerous. Finally, these reptiles suffer from habitat loss. All of these problems have taken their toll: timber rattlesnakes are declining in many states, including Missouri.
Why should we care that we're losing timber rattlesnakes? All snakes are important to the health of their ecosystems, being key links in the food chain -- and timber rattlesnakes are no exception.
What can you do to help these reptiles? First of all, don't buy any products made from timber rattlesnakes, and tell your friends and family to do the same. And if you happen to encounter the snakes in the wild, leave them alone! Remember, they won't attack unless they feel threatened -- so there is no reason to harm them.
- Male timber rattlesnakes engage in a special "combat dance" when they encounter each other, especially if a female is near. The males face each other with their heads and forward part of their bodies raised. They intertwine their necks, each trying to push the other to the ground to establish superiority.
- Timber rattlesnakes can recognize their siblings, even after they were separated at birth.
- Rattlesnakes are found only in the Americas.