The short, thick rostrum is poorly defined from the steeply sloping melon. The melon in Ziphius is relatively more bulbous than in Mesoplodon, but less so than Hyperoodon. The mouthline first sweeps downward from the rostral tip, then turns upwards toward the eye.

Adult males are generally slate gray over most of the body with a distinctive white head. The white coloration continues posteriorly along the dorsum. Adult female coloration appears more variable, ranging from dark gray to a reddish brown. The skin on the head of females is lighter, but does not contrast as dramatically as in males. Usually there are some distinctive patterns of dark pigment on the head of adult females. The eye is typically dark and there is a highly variable pair of dark crescents surrounding the eye, one anterior, and one posterior. Young animals are described as black or dark bluish black and lighter below. Light oval patches and linear marks are common on the skin. Oval scars are attributed to lampreys or cookie-cutter sharks.

Adult body length ranges between 5 to 7 m. Recorded maximum body length for adult males and females is 6.7 m, and 7.0 m, respectively. Length at birth is approximately 2.7 m.

Hyperoodon ampullatus
Hyperoodon planifrons
Mesoplodon mirus