Idahan practice swidden agriculture, the most important crop being rice; corn, bananas, sugarcane, tobacco, citrus fruits, etc., are also grown. Wet-rice agriculture is practiced only by three lowland groups. Fishing is important, much of it being done with poison and traps. Idahan raise pigs as a form of wealth; they are used for sacrifices and to pay bride-prices and fines; dogs are raised for hunting. Kelabits, on the other hand, raise rice, primarily through the use of irrigated fields, and also produce large numbers of cattle. The baya is their system of labor exchange, in which groups of workers farm each other's land in turn. Surplus rice and cattle, as well as salt, are important items of trade. Kelabit families own parcels of wet-rice land individually.