Snake Migration

Snake Migration

Illinois’s Shawnee National Forest is famous for its Snake Road.


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Biology, Experiential Learning, Geography, Human Geography, Physical Geography

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Many snakes travel across LaRue Road. It is in Shawnee National Forest, in Southern Illinois.

In spring, snakes move out of the forest. They slither into LaRue Swamp. In the fall, the snakes leave the swamp. They spend the winter by the bottom of limestone cliffs. The snakes like that it is dry there. This great animal movement is also called migration.

LaRue Road is between the cliffs and the swamp. It is also called Snake Road. LaRue Swamp is on the west side of the road. The swamp is part of the Mississippi River area. Animals such as the cottonmouth snake (Agkistrodon piscivorus) and the southern leopard frog (Lithobates sphenocephalus) live here. These animals are not usually seen as far north as Illinois.

The LaRue-Pine Hills are on the east side of the road. The LaRue-Pine Hills are famous for their beautiful limestone bluffs. The bluffs are 46 meters (150 feet tall). That is nearly as tall as the Leaning Tower of Pisa in Italy.

The limestone forms ridges and caves. These are great homes for snakes. They can stay cool in the summer and warm in the winter.

Crossing LaRue Road is dangerous for snakes. In the cool morning and evening hours, the road feels relatively warm. Snakes, frogs, toads, turtles, and other creatures like to hang out on the warm road. That is why so many get hit by cars.

Scientist Rich Seigel studies snakes. He said cars have killed almost one in every four snakes. Millions of snakes have been killed by cars in the United States.

In 1972, the government decided to close LaRue Road for short periods. This way, snakes can travel safely. The closings happen for two months each year in spring and fall.

At first local citizens were not happy about closing the road, Scott Ballard said. He is a scientist. He studies animals for the Illinois government. Over time, people changed their minds. They support the road closing now, Chad Deaton said. He is a wildlife scientist with the Shawnee National Forest.

Cars are not allowed. Yet, people can still walk along Snake Road. Ballard and Deaton said the walk is not as scary as it might seem. You "won't see a great river of snakes washing across the road," Ballard said. "If you see 20 snakes while you're out here, that's a good day."

Many people are afraid of snakes. However, they are important to nature's balance. They can be good for humans.

Ballard said, "A single snake can eat nine pounds in one year." That's equal to an entire pillowcase full of mice. Without snakes, there would be too many rodents around.

Also, birds such as herons eat snakes. If snakes were lost, the birds would have less food.

Questions For Biologists On The Snake Road

Q: How did you become interested in snakes?

A: Scott Ballard explained, "As a kid I was very allergic to dogs and cats. My mother gave me a pet snake when I was 10. After that I was hooked."

Q: Have you ever been bitten by a snake?

A: "Many times," Ballard said. Still, he has "never been bitten by a venomous snake."

"Once I was looking for a rattlesnake species. I'd lain down, turned my head and found one five inches from my eyes. She just looked at me and I looked at her." Ballard then "slowly got up and moved away."

Q: What should someone do if they're near a snake in the woods?

A: Stop and slowly step back from the snake, Chad Deaton said. Scott Ballard added, "Snakes are not mean. Snakes don't go out of their way to bite you. They only bite people when they are surprised or feel threatened."

Q: How many snakes are saved yearly when Snake Road is closed?

A: Ballard and Deaton said they weren't sure. Still, they see fewer snakes dead on the road. That is a good sign. It probably means more snakes are crossing safely.

Fast Fact

Are you scared of snakes? You might suffer from ophidiophobia. Ophidiophobia is a fear of snakes.

Fast Fact

There are only about 300 species of snakes in the world that are venomous. Of that number, only about half of them are able to kill humans with their bite. There are a dozen fatal snakebites in the United States every year. That's fewer than the number of people who are killed by beestings or struck by lightning.

On the other side of the world (and home to deadlier snakes, such as the cobra), more than 20,000 people die from snakebites every year in India.

Fast Fact

Snake Venom
Snake venom is extremely dangerous. It can also be medically useful. Some drugs developed from snake venom are used to treat disease.

Captopril comes from the jararaca (Bothrops jararaca), a viper from Brazil. Captopril works to lower blood pressure. Eptifibatide comes from the southeastern pygmy rattlesnake (Sistrurus miliarius barbouri), native to the southeastern United States. Eptifibatide prevents blood from clotting in the coronary arteries, the arteries supplying blood to the heart.

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Mary Schons
Jeannie Evers, Emdash Editing, Emdash Editing
Kara West
National Geographic Society
Last Updated

January 9, 2024

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