Harvester Crabs are two feet in diameter, discounting the legs, which add quite a bit more to the creatures. They live in hives that can span over a mile of coast line. They can be classified as workers or queens. The workers are most often found cutting down wild wheat and taking it into their underwater hives, but have been found doing many different tasks. Harvester crabs seem to have vaguely human ideas about agriculture, or at least their queens do.

The queens may be a seperate species than the workers, but appear to have a chemical way to give them instructions. They also seem to be able to communicate techniques to each other and to emulate other creatures, including man's knack for building. Queens live in groups of two to four, directing the workers, building strange underwater structures, and making themselves quite expressive to passerby.

Harvester Crabs reproduce by spawning, and form part of the plankton until they are grown, at which point they cease to float and settle down on a coast line. Most of the workers are found by queens and incorporated into a hive, but there are occasional loners, who are much less discriminate in what they gather.