Have you ever picked up a piece of rotting wood in your backyard and found those little roly-poly creatures hiding under there?

THOSE ARE ISOPODS!

... or rather those are one specific type of isopod. If you're from Rhode Island like us, you're probably thinking about a variety called "Armadillidium vulgare" or as they're more commonly known, "pillbugs" or "roly-pollies". But Armadillidium vulgare are just one of an entire order of creatures -- the order Isopoda.

Well... no. Not quite. While isopods are arthropods (just like insects), they're not part of the class Insecta (to which all insects belong). Isopods are actually crustaceans, specifically of the class Malacostraca (along with crabs and lobsters).

Well... some of them do. Giant isopods that live near the ocean floor and can grow up to 20" long, but unless you're a marine biologist, you probably don't have a tank big enough to hold one. (We certainly don't.) For this reason, we're concerned primarily with terrestrial isopods (like Armadillidium vulgare). The good news is that even the largest terrestrial isopods only reach about 1" in length (with many varieties being smaller than that.)

There's a number of reasons to keep isopods.

Some people use isopods as part of the cleanup crew in a bioactive vivarium. Isopods are great at recycling the fecal matter of larger animals and consuming decaying plant and animal matter (like dead feeder insects that no longer interest the vivariam's primary inhabitant). A bioactive vivarium seeded with isopods, springtails, and plants can significantly reduce the amount of thank cleanup required by pet owners.

Isopods also make a great first pet for children due to their limited needs and general hardiness. They also come in a variety of different colors and patterns which can make them a bit of a collectors item and colonies are often setup as a display piece.

Finally, some people use isopods as a treat food for their pets.