Prairie dogs: Selective cultivation
The social life of the prairie dog is not limited to defence. The adults, sitting outside their burrows, proclaim their ownership by giving yet another kind of whistle, accompanied by a small leap into the air. During the breeding season, the coterie members keep very much to themselves and defend their boundaries against any intruder. The prairie dogs tend the vegetation within the town with great care. Their grazing is so intense that many of the plants they favour become eaten out. The animals then move to a different part of their territory and let the old pasture recover. They also cultivate selectively. Sage, although one of the commoner plants is not a favoured food item. If a seedling of one takes root or if there is one growing in a newly colonized patch of territory, they do not simply ignore it but deliberately cut it down and so allow more room for the plants they prefer.