Adults average 36 inches in length. Heads are spade shaped and noticeably larger and thicker than the necks. At birth, cottonmouths resemble copperhead snakes with their light hourglass markings on a dark reddish background. Adults lose their juvenile coloration and become brownish black in color. Dark brown cheek stripes are edged with light lines. A pair of dark lines runs to the tip of the snout. Faint brown stripes encircle the body. The chin is a light cream color.