Timber Rattlesnakes Benefit Human Health by Preventing Lyme Disease

Rattlesnakes aren't immediately seen as beneficial to humans. With their venomous bite, these creatures are often viewed as threats. Now, though, scientists have discovered that the timber rattlesnake may be benefitting humankind by simply doing what it does best: eating rodents.

Rodents often carry ticks which, in turn, carry Lyme disease. This bacterial illness can cause serious neurological problems in humans if left untreated. Spread by ticks that infect hosts by feeding on their blood, Lyme disease is currently on the rise in the United States.

Normally, Lyme disease is controlled through predators. Foxes and other mammals can help control it by eating small rodents. Yet rattlesnakes also play a crucial role. In order to find out exactly how effective these creatures are at controlling Lyme disease, though, the scientists decided to see exactly how many rodents these snakes were consuming.

By using published studies of timber rattler's diets at four Eastern forest sites, the scientists were able to estimate how many small mammals the snakes consume. They then matched their estimates with information on the average number of ticks each small mammal carried. In the end, they found that each snake removed anywhere between 2,500 to 4,5000 ticks from each site annually--that's a huge benefit to humans.

While these snakes provide a major benefit, though, their numbers are quickly declining. Timber rattlesnakes are listed as endangered in six states and threatened in five more under the Endangered Species Act. As these top predators decline due to habitat loss, the risk of Lyme disease rises.

"Habitat loss, road kills and people kill them out of fear are the big issues," said Karen Lips of the University of Maryland in a news release. "They are non-aggressive and rarely bite unless provoked or stepped upon."

The findings reveal the importance of these top predators not only to the food chain, but also to humans. Since Lyme disease can be a major issue to human populations, ensuring that these snakes are properly protected will not only benefit forest ecosystems but will also benefit us, as well.

The findings are published online here.