Native to the Arctic waters of Canada, Russia, and Greenland, narwhals are surely among the most intriguing creatures in our oceans. Members of this whale species boast spiral ivory tusks that can reach up to 10 feet long.
Yet we don’t know exactly why narwhals, nicknamed “the unicorns of the sea,” have these unusual tusks, which are actually elongated canine teeth. One clue to the tusk's primary purpose is that nearly all male narwhals have tusks, whereas very few females do, suggesting that they may use it to assert dominance over other males and possibly attract mates.
Narwhals spend significant portions of their lives in the darkness of the deep Arctic, feeding far beneath the ice, so it’s not surprising that many of their behaviors, including the secondary uses of their tusks, remain a mystery to scientists. It’s thought that they may sometimes use them as weapons or tools for hunting fish, though as female narwhals lack tusks and are successful at finding food, this can’t be their primary purpose.
In 2022, researchers observed narwhals engaging in a surprising new behavior with their tusks. In drone footage recorded in the Canadian territory of Nunavut, narwhals were observed using their tusks to track Arctic char. The narwhals appeared to chase the char, using their long tusks to mirror their movements, flip, and stun them, yet the narwhals did not attempt to catch and eat the fish and ultimately let them go. The researchers conjectured that this could be “the first recorded evidence of play, specifically exploratory-object play, in narwhals.”
Though this behavior had never before been seen in narwhals, it aligns with previous observations of dolphins and whales engaging in play and underlines that narwhals are intelligent, social creatures.
The mysterious unicorns of the sea:
- In previous research, scientists discovered that a long tusk tends to correspond to large internal testes and better fertility, signaling to female narwhals that males with long tusks are attractive potential mates.
- Narwhals have also been observed swimming upside down near the ocean floor, possibly indicating that they use their tusks to disturb the sandy bottom and force their prey out of hiding.
- Narwhal tusks, which have up to 10 million nerve endings, could also have a sensory function, possibly for measuring water salinity, pressure, or temperature.
- In 2019, genetic sequencing confirmed that narwhals and their closest relatives, beluga whales, can successfully interbreed, with the discovery of an individual born to a male beluga whale and a female narwhal.
