Sixty police have been sent to northern Nigeria, where violence between farming and herding tribes has left at least two dead in a week of violence. There may be as many as three dozen dead, but hard information is difficult to come by. Most of the violence takes place in the bush. The region is just sough of the Sahara desert, and there's never enough water. Whenever there is a drought, the herders try to move in on farming land farther south.