Park rangers in Texas were left scratching their heads last week, trying to figure out what caused dozens, perhaps hundreds, of earthworms to wriggle onto a park road and form writhing pink balls.

The bizarre phenomenon was spotted last week in Eisenhower State Park by rangers cruising the park’s back roads. They noticed what appeared to be piles of spaghetti in the middle of the road.

Closer inspection revealed the “pasta” were actually worms, fully alive and moving. What was most odd was that each worm pile was lined up precisely down the road’s yellow double line.

Was it an elaborate mating ritual? A defence tactic? Global warming? Or were the worms dropped there by someone as a prank?

Park administrators posted pictures of the masses of wrigglers onto their Facebook page with the caption, “WHAT?! Can anybody explain this strange phenomenon?” They also added a video that elicited plenty of comments of “nasty” and “disgusting,” but still no good theory emerged about what the worms were doing.

Three days later, rangers at the park updated their Facebook page to say that all the worms had disappeared from the road, leaving behind only their droppings – and a lingering mystery.

Dale Overton, who studied ecology at the University of Manitoba, says he thinks he knows what happened. The owner of Overton Environmental Enterprises manages a large earthworm farm in Winnipeg and has gotten to know the ways of the worm.

He suspects that all the torrential rains that hit Texas recently probably flooded the worms out of their homes, causing them to seek higher ground on the road. Then, because they couldn't allow the mucous membranes on their skin to dry out, they huddled up on the highest part of the road, which happened to be along the yellow line.

“They actually ball together as a defence response,” he told

Overton said that while he can’t be certain that’s what happened in this case, he has certainly seen earthworms ball up together many times in times of stress.

“There’s really no telling what their thought process might be. I mean, they’re worms,” he said, “but that’s what I’m going to guess happened here."