The Shilluk keep small herds of cattle, in addition to larger flocks of sheep and goats. Cattle are normally used for food only in the context of ritual and ceremonial occasions. In the evening, the cattle are tethered around dung fires in an effort to lessen the adverse effects of biting flies and insects. Shilluk aggressively and successfully exploit the rich resources of the White Nile and regularly catch many species of fish with fishing nets and spears. They also hunt hippopotamuses. Less frequently, small hunting parties are organized to pursue antelope, buffalo, and giraffes. Hamlets are surrounded by gardens of millet, maize, and sesame, as well as other species introduced during the twentieth century. The Shilluk also cultivate tobacco for personal use and for sale. Herding, hunting, and spearfishing are primarily male activities; women traditionally have manufactured cooking utensils, cultivated gardens, and prepared food.