Narwhals may be using their tusks to play, new study finds

CNN

08-03-2025

(CNN) — Scientists say they have the first recorded video evidence of narwhals using tusks not only to strike and manipulate fish during feeding but also engage in what appears to be playful behavior, according to the latest research.
The narwhal, often referred to as the 'unicorn of the sea' in a nod to its trademark tusk, has long remained an enigma. Scientists have observed few interactions of narwhals in their natural habitat, creating speculation about the purpose of the species' distinctive spiraling tusk.
Found predominantly in males, the tusk grows up to 10 feet (3 meters) long — and previous research has suggested it serves as a competitive display to secure mates. But now, with the help of drones, research conducted in the Canadian High Arctic has uncovered that a narwhal may use its tusk for more than just courtship.
In total, the researchers newly identified and described 17 distinct behaviors of narwhals involving prey. The findings revealed a wide range of interactions and dynamics between narwhals and fish as well as the extraordinary agility, precision and speed of their tusks to track moving targets, according to the study published February 27 in the journal Frontiers in Marine Science.
'Seeing that these animals are not actually hunting the fish but exploring, manipulating and interacting with it was really a game changer,' said lead author Dr. Gregory O'Corry-Crowe, a research professor in the Harbor Branch Oceanographic Institute at Florida Atlantic University.
Since so little is understood about this whale species, researchers like O'Corry-Crowe and his colleagues are working diligently to conduct studies to document narwhals' unknown behaviors to better understand how these animals adapt in a rapidly shifting habitat as oceans warm and sea ice melts.
Narwhal exploratory behavior
The study team captured the groundbreaking footage using drones in Creswell Bay, on the eastern side of Somerset Island in Canada's Nunavut territory, during the summer of 2022.
As the researchers analyzed the footage, they noticed subtle nuances in the narwhals' behavior. Footage even captured one instance of a narwhal interacting with a fish by repeatedly nudging it with its tusk — which is actually a giant tooth — without attempting to eat it.
When researchers observed a lack of aggression in some interactions between narwhals and fish, they realized these scenarios were more similar to a cat-and-mouse game, in which the animals were chasing or 'playing' rather than hunting, O'Corry-Crowe said.
'Play is a very important aspect of developing behavioral skills that will be important in terms of survival in other ways, but the fact that they're engaged in this kind of work reminds us that these species have very complex and interesting lives,' O'Corry-Crowe said.
Younger narwhals also tended to imitate the behavior of older ones, indicating that social learning could influence how narwhals use their tusks, according to the study.
'(The) use of drones to study cetaceans has, in recent years, been revealing remarkable insights into previously undocumented behaviors,' said Anna Moscrop, head of science at Whale and Dolphin Conservation, an international charity dedicated to protecting whales and dolphins, via email. Moscrop was not involved in the study.
The research team worked around the clock, taking full advantage of the 24-hour daylight during the summer months to observe the narwhals.
O'Corry-Crowe emphasized the crucial role of collaboration with indigenous communities in the region, whose partnership and knowledge contributed to the success of the research.
Environmental adaptation
While the study mainly focused on tusk use, researchers also discovered other important behavioral shifts, particularly in narwhals' dietary habits.
The team found an unexpected predator-prey competition dynamic. Glaucous gulls — large gray-and-white seabirds that inhabit the Arctic — frequently attempted to steal fish from narwhals, significantly reducing the amount of prey they were able to catch.
Although gulls are known for stealing food gathered by land animals, there are few observations of seabirds stealing food from marine animals, Moscrop said.
In response to these challenges, narwhals may dive deeper into the ocean to hunt for larger or denser schools of fish, making the trade-off for easier catches more worthwhile, O'Corry-Crowe said.
Narwhals usually feed on deep-sea animals, such as squid or halibut. However, researchers observed narwhals hunting Arctic char closer to the ocean's surface, which is a shift in their hunting behaviors that raises concerns.
'We're in a race against time where we're trying to get in the field more to not only witness the impacts on (narwhal life) but also how they are hopefully trying to adapt,' O'Corry-Crowe said.
He said narwhals are likely adjusting their diet to account for environmental changes, such as rising ocean temperatures and increased human shipping activity in the area.
'Narwhals are highly sensitive and vulnerable to the effects of climate change because of the very close association of their lives with sea ice for food, navigation and refuge,' Moscrop said. 'The habitat range of the narwhal is changing and will be restricted as oceans warm.'