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Slimy, squishy, squiggly, wriggly. Apt descriptions for the underground denizens we call worms. Seemingly limp, hairless little creatures, the worms you see in your garden surprisingly do some very heavy work. You might just say they are the bald muscle men of the underground!

Worms don’t have a single bone in their body. But don’t let that fool you. Worms are quite muscular! They have muscles that go in circles around their bodies and other muscles that run the length of their bodies. By tightening their circular muscles, they can stretch into a thinner, longer self. The movement of relaxing and tightening the circular muscles also squeezes the front end of their body forward. The other long muscles squeeze together and help move the rear end of the body toward the front end. Without the help of arms or legs, a worm has to have good muscle tone to get somewhere!

A full-grown worm can have up to 170 rings or segments! If you could look really closely at the rings under a microscope you’d see what looks like a bunch of small hairs or bristles. The bristles are called “setae” and they act like brakes on a car. They help the worm slow down or stop.

Worms do feel kind of squishy. If you touch a worm you’ll notice that they’re a little wet or slimy. Worms don’t have lungs and if you take a close look, you’ll notice that worms don’t have a nose! How do they breathe? They breathe through their skin. The oxygen goes straight into their bloodstream. For that to happen, the worm’s skin has to be moist. The tricky part is that if the worm is in too much water, it will drown.

A worm’s mouth is quite tiny. Worms can only eat miniscule things like bacteria, fungi, and protozoa that we can only see through a microscope. They also eat plants and decaying animals. If a bit of food is too big for their mouths, they moisten the bits to make them soft and suck then right into their mouths! Since they have no teeth they can’t chew. Instead they have a gizzard. As they eat their food, some grains of sand and soil get into the gizzard. The grains of sand and dirt push against each other, mix with moisture and grind the tiny morsels. From there the food travels into the intestines and is absorbed into the blood. Then it carries the nourishment to all parts of the body to keep it strong, healthy and well, squiggley.

A muscular and well fed earthworm will go right to work turning the soil. They bring organic matter down from the top and mix it with the soil below, all the while creating pockets or tunnels underneath. This increases the amount of air and water that gets into the soil.

Worm poop is called castings and makes good fertilizer. If there were 500,000 worms squirming around an acre of soil, they could make 50 tons of castings. They would burrow through the soil and create a drainage system of tunnels equal to 2000 feet of 6-inch pipe! If you see worms in your garden it is a real good sign that you have healthy soil.

All that muscle-bound hard work is demanding; so demanding that worms have 5 hearts! All of them pump blood through their blood vessels just like your one heart! So the next time you happen upon what looks like a slimy, squishy, squiggly, wriggly worm, take a second look. It might just be the underground version of The Rock on his way to work.