The narwhal, often called the “unicorn of the sea” due to its distinctive long tusk, is indeed a type of whale. This Arctic marine mammal, scientifically known as Monodon monoceros, possesses characteristics that firmly place it within the whale family.
Understanding Whale Characteristics
Whales are aquatic mammals that share several key traits with other mammals, including breathing air, being warm-blooded, giving birth to live young, and nursing their offspring with milk. They also have hair, though it may be minimal and shed early in life, and possess three inner ear bones. These shared characteristics distinguish whales from fish, which breathe underwater using gills and lay eggs.
Narwhals belong to the suborder Odontoceti, which comprises the toothed whales. Unlike baleen whales (Mysticeti) that filter feed with baleen plates, toothed whales have teeth, although the narwhal’s dentition is highly specialized. This group includes other well-known marine mammals such as dolphins, porpoises, orcas (killer whales), and sperm whales. The narwhal’s closest living relative is the beluga whale; together, they form the Monodontidae family, sometimes referred to as “white whales.”
The Narwhal’s Distinctive Tusk
The narwhal’s most striking feature, its “tusk,” is actually an elongated canine tooth. Primarily found in males, this tooth can grow up to 10 feet long and exhibits a unique left-handed spiral. In rare instances, females may also develop a tusk, or a male might have two.
The tusk is a flexible structure with millions of nerve endings. It is considered an “inside-out” tooth, meaning its sensitive nerve-filled pulp is on the exterior, connecting directly to the ocean environment through microscopic channels. This unique anatomy suggests the tusk functions as a sensory organ. Research indicates it can detect changes in water temperature, pressure, and salinity, potentially helping narwhals navigate and sense ice formation.
Beyond its sensory capabilities, the tusk is thought to play a role in sexual selection, with larger tusks possibly indicating dominance among males. Drone footage has also revealed narwhals using their tusks to stun fish, suggesting a foraging function. Scientists continue to investigate the full range of its uses, including potential roles in communication and exploration.
Life in the Arctic
Narwhals are uniquely adapted to their Arctic habitat, primarily found in the cold waters of Canada, Greenland, and Russia. They possess a thick layer of blubber, accounting for about a third of their body mass, which provides insulation against frigid temperatures. This blubber also serves as an energy reserve and aids in buoyancy.
These whales are deep divers, capable of descending to depths of over 2,370 meters (7,780 feet) and remaining submerged for up to 25 minutes to forage for prey. Their diet primarily consists of Arctic and polar cod, Greenland halibut, squid, and shrimp, which they likely consume by suction feeding due to their limited dentition. Narwhals are social animals that travel in pods, usually ranging from two to ten individuals, though larger aggregations can occur during summer. They undertake seasonal migrations, often returning to the same summering grounds each year.