ADW: Monodon Monoceros - Animal Diversity Web

Physical Description

The narwhal is an easily recognized cetacean. Perhaps the most noticeable feature of the narwhal is the presence of a "tusk," which can grow to 3 m in length. The tusk is actually a canine tooth that protrudes out of the upper left lip in male narwhal. Narwhal have just two teeth; typically the left one erupts and the right tooth stays embedded. In most females both teeth stay embedded, however, it is possible for both sexes to exhibit one or two tusks. In the event of both tusks being present the left is always larger. All tusks spiral to the left, with a polished end and the rest of the horn being covered in algae.

Another unique physical characteristic is the lack of a dorsal fin. In place of a dorsal fin, narwhals have a dorsal ridge. The dorsal ridge and its notch pattern is unique, so it can be photographed and used to distinguish individual narwhal.

Another distinguishing characteristic is the change in narwhal coloration as they age. Narwhal are a dark blue-gray color at birth. As narwhals age, white begins to work into the dark color and create a mottled pattern. Adult narwhal have a dark mottled dorsal side and a cream colored ventral side. Old narwhal continue to get lighter and very old males can be mostly white in color.

Adult narwhals vary in length from 4 -5 m and range in weight from 900 - 1,600 kilograms. Newborn narwhals measure about 1.5 m in length and are usually around 80 kilograms. In a typical narwhal 30 - 35% of that weight is blubber. This layer of fat, ranging in thickness from 50 - 100 mm, is essential for the survival in Arctic waters. Narwhals can also be identified by their fins, which are smaller than those of most other cetaceans and have a distinctive tip that curls up.

• Other Physical Features
• endothermic endothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• male larger
• ornamentation ornamentation

Range mass 900 to 1600 kg 1982.38 to 3524.23 lb Range length 4 to 5 m 13.12 to 16.40 ft