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There are tens of thousands of types of worms on our planet, and these wiggly wonders are oh-so fascinating that we had to put together different stories about them to reveal just how 'wormdeful' they are.

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Why Do Earthworms Come Out After It Rains?

This Worm's Gut Has No Way In or Out

This Flatworm Remembers Things After You Cut Off Its Brain

Why Don't Humans Get Heartworm?

Why You Might Want Parasitic Worms

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You might think worms are boring and gross, and it's true that they're often a bit slimy. But they're anything but bland. Between true worms, flatworms, roundworms, and all the other things we lump together as worms, there are tens of thousands of different kinds of worms on this planet.

And they're unbelievably complex and fascinating. In fact, we can learn a lot about ourselves by studying them. So today, we're bringing together science stories about different sorts of worms, to reveal just how wormderful they are.

Let's start with the worms you're probably most familiar with: earthworms. They're a favorite of composters and fishing enthusiasts alike. And if you're looking to grab a few for either purpose, you'll probably have the best luck after a rainstorm. Here's Olivia, with what we know about why that is.

After a heavy rainstorm, you've probably seen worms popping out of the soil, getting stranded all over sidewalks and parking lots. But between birds, clumsy humans, and the sun, it's dangerous for a worm to climb out of its safe, cozy burrow. And yet they suddenly abandon ship whenever it starts raining.

Scientists have come up with plenty of possible reasons why rain might trigger this behavior, but they don't quite agree on all of them. The oldest hypothesis, and one you might've heard, is that earthworms surface to avoid drowning. That's because worms take in oxygen through their skin in a passive process called diffusion, where oxygen moves from the higher concentration outside their bodies, to the lower concentration inside.

When soil floods after a rainstorm, worms can usually still breathe if there's enough oxygen dissolved in the water. But, water is a lot denser than air, so diffusion is much slower. Like, up to a thousand times slower. Which means that for a worm, it could be a lot harder to breathe after a downpour, which could make them rush to the surface.

But some biologists have pointed out that plenty of worms can actually live for days submerged in water, although some of that may depend on the species.

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