When Clemson University senior Nathan Weaver first placed a rubber box turtle in the middle of a road, he was simply researching ways to help real turtles safely cross the street. But he witnessed something chilling he hadn’t expected: Several drivers went out of their way to run over the turtle.

The first time he conducted his experiment, Weaver put the realistic-looking turtle in the middle lane of a road near a college apartment complex in Clemson, S.C. Then he watched for an hour as 267 vehicles passed by and seven drivers intentionally ran over the turtle. Several more tried to hit the rubber animal but missed.

"It was a bit surprising. I've heard of people and from friends who knew people that ran over turtles. But to see it out here like this was a bit shocking," Weaver told the Associated Press.

Although Weaver was shocked to see such behavior, research shows that drivers intentionally running over the reptiles is not uncommon.

Box turtle populations are in slow decline, and one of the main reasons is the riskiness of crossing streets, which can take turtles several dangerous minutes. A 2002 study of the impact of road density and traffic volume on turtle populations found that roadkill alone contributed enough mortality to reduce the size of a local turtle population.

What makes the problem even worse is that turtles reproduce slowly. It takes seven or eight years for a turtle to reach sexual maturity, and during that time, a turtle likely makes several trips across streets in search of food or nesting areas.

A 50-year-old turtle might lay more than 100 eggs over its lifetime, but statistically only two or three of those hatchlings will survive long enough to reproduce, according to Rob Baldwin, a professor at Clemson's School of Agricultural, Forest and Environmental Sciences.

Curious if other drivers were just as likely to run over his rubber turtles as those near campus, Weaver chose a residential street next to duplicate his experiment. He placed a turtle in the middle lane of the road and waited.

The second car that appeared swerved over the center line of the road and ran over the turtle, destroying its plastic shell. For the rest of the hour, no other cars hit the fake animal, but just as Weaver went to retrieve it, another car pulled to the right to hit the turtle.

"One hit in 50 cars is pretty significant when you consider it might take a turtle 10 minutes to cross the road," Weaver said.

Why would someone go out of the way to run over a defenseless animal?

Hal Herzog, author of a book about our relationships with animals called "Some We Love, Some We Hate, Some We Eat,” says it can be about asserting dominance over another species. But sometimes it’s just about having fun.

"They aren't thinking, really. It is not something people think about. It just seems fun at the time. It is the dark side of human nature," Herzog told the Associated Press.

To illustrate his point, Herzog, a Western Carolina University psychology professor, asked one of his classes if they’d ever intentionally run over a turtle or been in the car with someone who did. Of the 110 students, 34 raised their hands and two-thirds of them were male.

What do if you find an injured turtle in the road

If you can safely retrieve the animal, do so. Place the turtle in a box and keep it in a dark, quiet area indoors.

If there’s debris on the turtle, you can wipe it off with damp gauze, but do not rinse the animal with running water or immerse it in water. If there’s a limb injury, pack a piece of gauze over the limb and wrap gauze around it to hold it in place.

It’s best to let a veterinarian or wildlife rehabilitation expert evaluate the turtle before it eats, so don’t offer the animal any food. You can locate a wildlife rehabilitator or vet that treats wildlife here.

More turtle stories on MNN:

Laura Moss writes about a variety of topics with a focus on animals, science, language and culture. But she mostly writes about cats.

Some drivers go out of their way to hit turtles
A Clemson University student found that 1 in 50 drivers intentionally hit box turtles, a species that's in decline.