As one of the world's most unique whales, narwhals have many unusual adaptations, including their reliance on a specialized diet and the long, horn-like tooth of the males. According to the National Oceanic and Atmospheric Administration, scientists still have many questions about some of these adaptations, especially the function of the males’ long tooth. Additionally, narwhals are capable of diving to depths of nearly 5,000 feet below the surface.
The National Oceanic and Atmospheric Administration contends that narwhals primarily survive by eating Greenland halibut, cod, shrimp and squid. Because the narwhals capture their prey in the dark depths of the ocean, it is impossible to study their feeding habits firsthand. Some scientists speculate that the long tooth of males plays a role in feeding, but others argue that because the tooth is absent from most females, it likely serves a social role.
As explained by the Society for Marine Mammal Science, narwhals have the northernmost range of any whale or dolphin in the world, often inhabiting the area between 70 and 80 degrees north latitude. In much of this range, the whales live under the pack ice. As an adaptation to this, narwhals have very reduced dorsal fins relative to other whales.