They choose and often swap shells. Who knows, this could just be a fad. The more conservative crabs probably mock these youngsters for their flashy colors, eve

They choose and often swap shells. Who knows, this could just be a fad. The more conservative crabs probably mock these youngsters for their flashy colors, even though human offcast glass and aluminum are probably lighter, stronger, objectively better for the purpose the crabs have. The old ways, living in the corpses of your neighbors, were better.