By Steve Roark
Volunteer Cumberland Gap National Historical Park

If you've ever picked up an old board or a rock that's been lying on the ground a while, you've no doubt found pillbugs, which live in moist, dark places. They are also known as sowbugs or rollie poley bugs but are called Isopods by the science guys.

The common pillbug (Armadillidium vulgare) is classified as a crustacean, and are kin to lobsters, shrimp, and crayfish. They breathe through gill-like structures and so need a very moist environment to survive. They cannot breathe underwater. Isopods are harmless to humans and perform the important function of eating rotten or dying plant material and enriching the soil with their excretions. They do not see well, and depend heavily on smell, which they sense through their antennae. Because they need moisture, they even have humidity seeking scanners.

There are other oddities about pillbugs that make them unique critters. Every kid on the planet has no doubt messed with them until they curl up into a ball (hence the name), which is a defensive maneuver. Like other crustaceans, pillbugs tote their eggs around with them in a special pouch called a marsupium. Also, pillbugs do not urinate. One of the reasons we pee is to get rid of toxic ammonia gas, which our body converts to liquid urea for excretion. Pillbugs simply pass ammonia gas out through their exoskeleton, so they don’t have to pee, but do have a lot of flatulence.

Pillbugs are able to drink water not only through their mouth, but also through their anal opening (we are now leaving unique and moving on to weird). They eat their own poop… actually, they eat other animal’s poop too, but they eat their own to recover the element copper, which they need a lot of to function (weird just showed up in the rear-view mirror). Impress your friends by knowing what coprophagy means, which is the eating of feces or dung. Final weird fact: Pillbugs have blue blood. Hemoglobin is what carries oxygen in our blood, which is red because it’s iron based. Pillbug blood uses something called hemocynain to carry oxygen around, which is copper based, and so has a blue color. As with most things in nature, there’s more to a pillbug than meets the eye.