How big is a narwhal whale?

Quick Answer

A fully grown narwhal (Monodon monoceros) is a medium-sized cetacean. Adults typically reach a body length of 13 to 18 feet (4 to 5.5 meters) and weigh between 1,700 and 3,500 pounds (800 to 1,600 kilograms).

While their body size is comparable to their closest relative, the Beluga Whale, male narwhals appear significantly larger due to their defining feature: the tusk. This spiral canine tooth protrudes from the upper lip and can grow up to 10 feet (3 meters) long. When including the tusk, a large male narwhal can reach a total length of nearly 28 feet. Females are generally smaller than males and rarely grow a tusk.

For more details on this unique Arctic species, visit our Narwhal profile.

What You Need to Know

Determining exactly “how big is a narwhal whale” requires looking at more than just a tape measure. As one of the most specialized Arctic inhabitants, the narwhal’s size is perfectly adapted for life amidst the pack ice. Their robust, stocky build helps them conserve heat, while their lack of a dorsal fin allows them to navigate beneath frozen surfaces.

Body Dimensions and Weight

In the world of cetaceans, narwhals fall into the “medium” category. They are dwarfed by giants like the Blue Whale but are significantly larger than most dolphins and porpoises.

• Length: Without the tusk, adult narwhals average between 13 and 16 feet (4 to 5 meters). Exceptional individuals can reach 18 feet (5.5 meters).
• Weight: Their weight fluctuates seasonally but generally falls between 1,700 and 3,500 pounds (800 to 1,600 kg).
• Girth: They are rotund animals, with a thick layer of blubber that constitutes nearly 30% to 35% of their total body mass.

This substantial layer of blubber is critical for Size & Weight considerations. While they may look smaller than leaner whales, their density is high. This heavy insulation is necessary for survival in Arctic waters that often hover near freezing temperatures.

The Tusk: A Massive Tooth

The most common question regarding narwhal size involves their tusk. It is important to note that scientific measurements of whale length usually exclude the tusk, measuring only from the tip of the jaw to the notch in the tail flukes. However, the tusk adds considerable visual size.

The tusk is actually an enlarged canine tooth that spirals out through the upper lip.

• Length: It typically grows 5 to 10 feet (1.5 to 3 meters).
• Weight: A hollow, spiral tusk can weigh roughly 22 pounds (10 kg).
• Occurrence: It is found primarily in males. Only about 15% of females grow a tusk, and theirs are usually shorter and less spiraled. Roughly 1 in 500 males will grow two tusks.

Because of this appendage, a male narwhal cuts a much more imposing figure in the water than a female, despite their bodies being relatively similar in mass.

Sexual Dimorphism

Unlike the massive Sperm Whale where males are nearly three times the size of females, narwhals show moderate sexual dimorphism.

Males are slightly larger and heavier than females even without accounting for the tusk. A mature male might weigh 3,500 pounds (1,600 kg), while a mature female might top out around 2,200 pounds (1,000 kg). This size difference is common in toothed whales but is less extreme than in some other species.

Growth from Calf to Adult

The lifecycle of a narwhal begins at a size that is already impressive by terrestrial standards.

• Newborns: Narwhal calves are born at approximately 5 feet (1.5 meters) in length and weigh about 175 pounds (80 kg).
• Juveniles: They grow rapidly on their mother’s high-fat milk. By the time they are weaned (around 1-2 years), they have significantly increased their blubber stores.
• Maturity: Females reach full size and sexual maturity around 6 to 8 years of age, while males mature slightly later, around 9 years old.

Anatomical Adaptations Affecting Size

The shape of a narwhal is distinct. They lack a dorsal fin—the fin on the back found on most whales like the Killer Whale. Instead, they have a low, irregular dorsal ridge.

This adaptation reduces their vertical height, allowing them to swim safely immediately under the sea ice to avoid predators or find breathing holes. While this makes them “smaller” in profile, the dorsal ridge is tough and callous, used to break thin ice when surfacing for air.

Their vertebrae are also unique. Like land mammals (and unlike most whales), narwhals have neck vertebrae that are not fused. This gives them a flexible neck, allowing them to turn their heads to scan their environment—a useful trait for navigating narrow ice channels.

Comparisons to Other Whales

To visualize the narwhal’s size, it helps to compare them to familiar species:

• Vs. Beluga Whales: The Beluga is the narwhal’s closest living relative (both belong to the family Monodontidae). They are almost identical in body size, though Belugas are often slightly bulkier and can be heavier.
• Vs. Orcas: An Orca is significantly larger, with males reaching up to 32 feet and weighing over 6 tons. An Orca could easily overpower a narwhal, which is one reason narwhals hide in deep pack ice.
• Vs. Humans: An adult narwhal is roughly the length of a large SUV or a pickup truck. Including the tusk, a male is as long as a small school bus.

If you are wondering about the classification of these animals, check out our guide: is a narwhal a whale.

Key Takeaways

• Body Size: Narwhals are 13–18 feet (4–5.5 m) long and weigh up to 3,500 lbs (1,600 kg).
• The Tusk: The spiral tusk is a tooth that adds an extra 6–10 feet (1.5–3 m) to the length of males.
• Dimorphism: Males are larger and heavier than females; females rarely possess a tusk.
• Adaptation: Their stocky, blubber-rich bodies and lack of a dorsal fin are adaptations for Conservation of heat and movement under Arctic ice.
• Growth: Calves are born roughly 5 feet long and grow rapidly to survive the harsh polar environment.

For more information on how these animals survive in their frozen habitat, read where do narwhal whales live.