An isopod is an animal that has fourteen legs, seven pairs, that all function equally. They do not have legs that have been specialized to perform any specific function, and each leg can perform each of the functions as any of the others.
Isopods reproduce sexually, as there are both male and female animals. After mating, the female will carry her eggs in a specially adapted pouch, much like a kangaroo pouch, on the underside of her abdomen. The eggs will mature in approximately three weeks and the young will then hatch, as almost perfect clones of the mother, with the exception of missing the last pair of legs (the thoracic legs), which will develop as the isopod matures. These hatchlings are already able to fend for themselves and do not depend on their mother for food or protection.
Most immature isopods are so tiny that they are almost invisible to the naked eye, but grow quickly, reaching a mature size within several weeks or hatching. As the isopods grow and mature they will shed their hard outer layer (exoskeleton) several times before reaching their full adult size. The shedding, or molting, occurs in two phases, which is unique to this order of crustaceans, as most will accomplish this feat in only one stage. The rear section of the hard shell will be lost first, and then the front section. The sloughed shell will reveal a soft, new exoskeleton that will harden in an hour or so.
The life expectancy of an isopod is pretty short, as with most other crustaceans, though it is generally much longer than insects. The lack of a water phase in the life cycle of the isopod limits its ability to move fare from its original place of birth, which is why there are normally large populations of isopods in a particular area and none in another.
Isopods belong to an order of animals known as cryptozoa, or hidden animals, preferring to inhabit shady, moist, cool areas such as under rocks, forest vegetation, and rotting logs, though they can be found almost anywhere there is shade and moisture. They enjoy a large variety in their diets and can become a minor garden pest. They must ensure that they remain in moist environments in order to keep from drying out.
Isopods are not insects, but crustaceans. Insects are identified by having three sets of paired legs, isopods have seven. Isopods are one of the only animals in the crustacean order that does not have a water phase in their development.