Rustling is the act of stealing cattle, usually by moving them from one place to another without the owner's permission. Rustling has been a problem since the days of the Wild West, when cattle were a valuable commodity and could be sold for a high price. Rustling is still a problem today, with some estimates suggesting that up to $1 billion worth of cattle are stolen each year in the United States alone. Rustle, as cattle, is an apt description of this illegal activity.