Timber Rattlesnake: This Fearsome Creature Helps Control the Spread of Lyme Disease


Story at-a-glance -

  • According to recent research performed by a team at the University of Maryland, the timber rattlesnake benefits humans by helping to keep Lyme disease in check.
  • The timber rattler is a venomous pit viper, and the only species of rattlesnake found in the northeastern U.S. It’s impressive size (up to 60 inches), long fangs, and the amount of venom it delivers makes this snake one of North America’s most dangerous.
  • Like foxes and other mammal predators, the timber rattlesnake feeds on mice and other small animals infected with the bacteria that causes Lyme disease. And like those mammal predators, the timber rattler’s numbers are also dwindling. Scientists believe declining populations of predators are a factor in the rise of Lyme disease in humans.
  • The University of Maryland research concluded that timber rattlers eliminate from 2,500 to 4,500 ticks yearly in each location they inhabit, suggesting that this type of predator plays an important role in controlling the spread of Lyme disease through predation on small mammals.
  • Timber rattlers are endangered in six states and threatened in another five as a result of habitat loss, road kills, and people killing them out of fear.

By Dr. Becker

The timber rattlesnake, a native North American viper with the impressive scientific name Crotalus Horridus, inspires dread and disgust in many people.

But like all creatures loathsome and otherwise, this snake serves a purpose in the Earth’s ecosystem. And as it turns out, according to recent research by biologists at the University of Maryland, the timber rattlesnake indirectly benefits humans by keeping Lyme disease under control.

According to Science Daily, these findings, which were presented at the recent annual meeting of the Ecological Society of America, “highlight the potential benefits of conserving all species – even those people dislike.”

Crotalus Horridus

The timber rattlesnake, also known as the canebrake rattlesnake or banded rattlesnake, is a species of venomous pit viper. It’s the only rattlesnake species found in the northeastern United States.

The average adult size of a timber rattler is from 36 to 60 inches, with the longest on record 74.5 inches. It’s a large, heavy-bodied snake with a pinkish gray or tan body. It has a reddish-brown stripe running down the center of its back with large black crossbands. The scales are keeled (dull rather than shiny) and the tail is black, ending in a rattle.

Timber rattlers have large heads and sometimes there is a dark line running diagonally through or just behind the eye. The pupils are cat-like and there is a facial pit between the nostril and the eye. The facial pit detects body heat, enabling the snake to find warm-blooded prey in the dark. It is this facial pit that places the timber rattler in the pit viper family.

Timber rattlesnakes feed mainly on small mammals, but are also known to eat small birds, frogs and other snakes (primarily garter snakes).

This snake is considered to be one of North America’s most dangerous, due to its size, long fangs, and the quantity of venom it delivers.

Lyme Disease in Humans Is On the Rise

The incidence of Lyme disease in humans has increased in recent years. The disease is spread by black-legged ticks that feed on infected mice and other small animals.

Foxes and other mammal predators help control the spread of Lyme by preying on the small mammals that harbor the bacteria that causes disease. But populations of these predators have been in decline, which scientists believe may be a factor in the rise in cases of human Lyme disease.

Timber rattlesnakes also happen to be well-established predators in forests in the Eastern region of the U.S., and like mammal predators, their populations are dwindling. So Maryland graduate student Edward Kabay decided to find out if the rattlers also help to control Lyme disease.

Timber Rattlesnakes Eliminate Thousands of Ticks from Forests Each Year

Kabay consulted studies of the diets of timber rattlesnakes in four locations in the northeastern U.S. to learn the approximate number of small mammals the snakes consume. He compared that number with the average number of ticks each mammal carries. Kabay’s results indicate that timber rattlers wipe out 2,500 to 4,500 ticks in each location.

From the Ecological Society presentation abstract:

Our model results suggests apex predators like many species of vipers may play important roles in regulating incidence of Lyme disease through predation on small mammals. Timber rattlesnakes populations are declining under pressure from decreasing habitat and overharvest, especially in northern and upper midwestern populations where the incidence of Lyme disease is the highest. Our research highlights the importance of biodiversity for human health and identifies several research areas on the effectiveness of ecological education and conservation efforts for these important predators.

Under the Endangered Species Act, timber rattlesnakes are endangered in six states and threatened in another five. According to Karen Lips, an associate biology professor at UM, “Habitat loss, road kills, and people killing them out of fear are the big issues. They are non-aggressive and rarely bite unless provoked or stepped upon.”

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