Males usually are larger than females. Coloration of wild forms is dark gray to black or brown. The body is covered with stiff bristles and usually some finer fur, but the pelage often is quite scant, and the tail is only lightly covered with short hairs. Many individuals have side whiskers and a mane on the nape. The young are striped.
Hogs have four continually growing tusks, two in each jaw.
There are three pairs of mammae in female S. salvanius and six pairs in females of the other species. Individuals construct crude shelters by cutting grass and spreading it over a given area. They crawl under the grass and then raise themselves to lift the grass mat, which then attaches to uncut grass and forms a canopy. They wallow in mud and will do so for hours if the opportunity affords. They are swift runners and good, strong swimmers.