What's the real reason sidewalks are so full of worms after it rains?

It may not be the reason you think.

Image by iGlobalWeb from Pixabay

(CHICAGO) It's been a wet spring for Chicago with no signs of ending soon. All that rain has brought earthworms wriggling their way to the surface and splaying themselves all over the sidewalks.

You may have had to do a lot of dodging of wriggling worms this spring if you're the type of person that's bothered by them. Unless, of course, you decided to stay home until worm season is over.

Why so many worms on the sidewalk?

Common wisdom used to be that earthworms found their way above ground when it rains because they would otherwise drown in the floods.

However, most scientists agree this is not truly why worms make their way to the surface after a lot of rain. And it's not why we've been finding so many worms on sidewalks during the latest Chicago rains.

The real reason for all the worms

Chris Lowe, a researcher at the University of Central Lancashire, told Scientific American that earthworms breathe through their skin, and they need moisture to do so. When it rains, they leave dry areas and seek out moisture in the ground. They can live for days fully submerged in water.

According to the article, there are several theories why earthworms may come to the surface when the ground is wet.

• It's easier to migrate through wet soil than dry.
• Some types of worms come to the surface to mate.
• Raindrops cause vibrations on the surface of the soil. It's the same sound to worms as if moles or another predator is after them. They often come to the surface to escape from moles.

What types of worms do we see in Chicago?

• The nightcrawler is an earthworm commonly found throughout Illinois. It's native to Europe and is an invasive species in North America.
• The southern worm can also be found throughout the state. It's smaller than a nightcrawler and has a gray appearance.
• The woodland white worm turns blue when it's full of soil. It's commonly found in Illinois in wet soil.
• The invasive jumping worm is a destructive species first identified in Illinois in 2015.

A "wormnado" in New Jersey

At least there have been no reports in Chicago of what a woman in New Jersey discovered one day. According to Live Science, she took pictures of a massive spiral of worms and sent them to Hoboken City Councilmember Tiffanie Fisher, who shared the images on Facebook.

So the next time you have to dodge worms as you walk down the sidewalk on a rainy Chicago day, you can be glad it's not a "wormnado."

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