Like the beaked whales discussed on p. [70] through [83], the northern bottlenosed whales have no notch in the tail flukes, have two throat grooves forming a V-shape on the chin, and have only two teeth in the lower jaw, with those teeth emerged from the gums only in adult males. These teeth may have sometimes fallen out of older males, but the tooth sockets should still be visible in the gums.

NOTE: Some specimens—both male and female—will be found to have a series of vestigial teeth the size of toothpicks in the upper and/or lower jaws. Similar vestigial teeth, 5-40 in number, sometimes occur in goosebeaked whales (p. [70]). Further when they are prepared for museum collections, the lower jaws of adult northern bottlenosed whales may be found to contain a second pair of teeth just behind the first.

Northern bottlenosed whales may be distinguished from the remainder of the beaked whale family, however, by the extremely robust body, by the bulbous forehead, which is more extensively developed in larger animals, particularly males, and by the pronounced dolphinlike beak.

Figure 68.—Views of the heads of male northern bottlenosed whales off Nova Scotia. Note the distinctive beak ([right]) and the bulbous forehead, features which develop with age and are most pronounced in adult males. In the animal on the [left], note also the low bushy blow emanating from the indented area on the top of the head. (Photos by H. E. Winn.)