How Human Noise Disrupts Narwhal Behavior
Narwhals, the elusive “unicorns of the sea,” are a type of whale, specifically a toothed whale, with the scientific name Monodon monoceros. The name 'narwhal' comes from the Old Norse term for 'corpse whale,' referencing their grey, mottled skin that resembles a drowned sailor. Their legendary status as “unicorns” comes from their single, spiraled tusk, which has inspired myths and fascination for centuries. This tusk, often called a 'one horn,' is directly linked to the unicorn myth, with narwhals historically believed to be the source of the fabled unicorn horn. As a toothed whale, male narwhals typically have two teeth, with one developing into the iconic spiral tusk.
Narwhals depend on sound for survival in the Arctic’s dark, icy waters. But as human activities expand northward, underwater noise from ships, industrial development, and even military sonar is disrupting their ability to communicate, navigate, and feed. This growing threat could reshape narwhal behavior and jeopardize their long-term survival.
Narwhals are found throughout the Arctic Ocean, including northern Canada, eastern Russia, and important habitats such as Baffin Bay.
Why Sound Matters So Much to Narwhals
In the Arctic, visibility is limited for much of the year due to sea ice and low light. Narwhals rely heavily on echolocation—sending out clicks and listening for returning echoes—to find prey like halibut and cod at depths exceeding 1,500 meters.
Echolocation is essential for hunting in complete darkness.
The narwhal’s most distinctive feature is its long, spiral tusk, which is actually an elongated tooth that grows from the upper jaw. Narwhals have two teeth, with one forming the tusk.
Narwhals also produce whistles and pulsed calls to communicate with pod members.
Their hearing is adapted to detect subtle acoustic cues in the environment.
Narwhals often forage in deep water for prey.
Disrupt these soundscapes, and you disrupt the very systems narwhals depend on to survive.
Learn more about narwhal hunting depths in our Narwhal Facts page.
Sources of Human Noise in the Arctic
The Arctic was once one of the quietest oceans on Earth. That is changing rapidly:
1. Commercial Shipping
With sea ice receding, shipping lanes through the Northwest Passage and Northern Sea Route are opening. Large vessels generate constant low-frequency noise that can travel hundreds of kilometers underwater.
External source: The International Council for the Exploration of the Sea (ICES) has documented rising Arctic shipping traffic in its Marine Noise in the Arctic report. Marine science research is crucial for monitoring and understanding the impacts of noise on Arctic ecosystems.
2. Industrial Development
Oil and gas exploration involves seismic airgun blasts—one of the loudest human-made sounds underwater. These can mask echolocation clicks for minutes at a time.
3. Naval Sonar
High-intensity sonar used for submarine detection can cause panic dives, disorientation, and in extreme cases, strandings.
For more on how narwhals navigate changing Arctic waters, see our post on Narwhal Migration.
How Narwhals React to Underwater Noise
Scientific studies, including those led by Dr. Martin Nweeia, have shown that narwhals respond to human noise in ways that can compromise survival. Another leading researcher in narwhal behavioral and population studies is Peter Heide Jørgensen:
Freeze Response: Narwhals often stop moving entirely when startled, perhaps to avoid predators such as polar bears—but this can lead to lost feeding opportunities.
Faster Swimming: In some cases, they swim away quickly, burning precious energy reserves needed for the long Arctic winter.
Abandoning Key Habitats: Persistent noise can drive narwhals away from feeding and calving grounds, forcing them into less optimal areas, including critical regions like Lancaster Sound, Davis Strait, West Greenland, and Northern Hudson Bay.
Narwhal social groups can consist of adult males, adult females, female narwhals, male narwhals, and juveniles. Larger groups may form during migration or in key habitats such as Lancaster Sound, Davis Strait, West Greenland, and Northern Hudson Bay. Male narwhals, especially adult males, use their tusks in dominance displays, and males and females have different roles in group structure.
📎 Read more about Dr. Nweeia’s research.
The Risks of Chronic Noise Exposure to Narwhals
Unlike a single loud event, chronic noise can lead to long-term impacts:
Reduced Foraging Efficiency – If echolocation is masked, narwhals may catch fewer fish. The narwhal diet consists mainly of Arctic cod, Greenland halibut, and polar cod, which are often found beneath dense pack ice, making effective foraging especially challenging under noisy conditions.
Increased Stress Hormones – Prolonged exposure to disturbance elevates stress levels, which can affect reproduction. Chronic stress may also impact the age at which narwhals reach sexual maturity and their ability to successfully raise a single calf.
Disrupted Migration – Altered routes may put narwhals in areas with more predators or less food. Narwhals tend to follow specific migration routes and dive to great depths during their seasonal movements; chronic noise can interfere with these migration narwhals behaviors and their ability to reach important habitats.
External research from the National Oceanic and Atmospheric Administration (NOAA) emphasizes that chronic noise can have “population-level consequences” for marine mammals. The long-term impact of chronic noise on narwhal reproduction remains unknown. Read NOAA’s marine noise impact overview.
Climate Change Makes the Problem Worse
Climate change is a double-edged sword for narwhals when it comes to noise:
Less Sea Ice = More Ship Traffic – Quieter, ice-covered seas are giving way to open-water shipping lanes. Changing ice conditions and the reduction of pack ice make narwhals more vulnerable to noise and other threats, as pack ice provides critical habitat and protection.
Changing Prey Availability – Narwhals may have to travel farther for food, increasing the likelihood of encountering noisy human activity. Like many Arctic animals, narwhals are also affected by changes in oceans Canada, including pollution from heavy metals that can accumulate in their organs and pose health risks.
This combination of stressors could push narwhal populations beyond a tipping point.
Steps to Reduce Noise Pollution in the Arctic
Conservation groups, scientists, and Indigenous communities are advocating for solutions:
Seasonal Shipping Restrictions – Limiting traffic during sensitive periods such as calving or migration.
Quiet Ship Technology – Designing propellers and hulls to reduce noise output.
Marine Protected Areas (MPAs) – Establishing zones where industrial activity is restricted. Narwhals are closely related to belugas and bottlenose dolphins, and conservation efforts in these areas help protect young narwhals and other vulnerable Arctic marine mammals.
Involving Inuit Knowledge – Inuit hunters and elders possess deep understanding of narwhal behavior and can guide policy decisions.
Additionally, narwhals are listed under Appendix II of CITES, which provides international regulatory protections and trade restrictions for the species.
The Canadian Inuit Tapiriit Kanatami organization emphasizes the need to integrate traditional ecological knowledge into Arctic management strategies.
Why This Matters Now
Narwhals are an indicator species for Arctic health. If their behavior changes dramatically due to noise, it signals deeper ecosystem disruption. Protecting them is not just about one species—it’s about safeguarding the soundscape of the Arctic for all marine life.
By recognizing and reducing human noise in the Arctic, we can give narwhals the best chance to adapt to the other challenges they face in a warming world.
References
ICES: Marine Noise in the Arctic
NOAA: Marine Noise Impact Overview
Inuit Tapiriit Kanatami