Very large soil animals, such as moles, rabbits, woodchucks, snakes, prairie dogs, and badgers, burrow in the soil and spend at least some of their lives below ground. Moles are secondary consumers, their diet consisting mainly of earthworms. Most of the other animals exist on vegetation. In many cases, their presence is considered a nuisance for agricultural production or lawns and gardens. Nevertheless, their burrows may help conduct water away from the surface during downpours and thus decrease erosion. In the southern U.S., the burrowing action of crawfish, abundant in many somewhat poorly drained soils, can have a large effect on soil structure. (In Texas and Louisiana, some rice fields are “rotated” with crawfish production.)