Narwhals may use their iconic tusks to play

Narwhals wield their iconic tusks in surprising ways — possibly even to play with newfound toys.

Aerial videos showed the Arctic whales swinging their “horns” to thwack fish prior to eating them, and in one case, gingerly prodding and flipping a fish. The gentler movements may have been part of a narwhal play session, researchers report February 28 in Frontiers in Marine Science. It’s the first reported evidence of narwhals (Monodon monoceros) likely amusing themselves for fun.

Few scientists have seen the apparent unicorns of the sea brandishing their tusks in the wild. The elongated, spiraled tooth protrudes from the top lip of males and some females, and can grow to around half the body length of the roughly 4.5-meter-long whales. Scientists suspect the tusk evolved in males to show off to or compete (even literally) for mates. But past research has found it has other benefits, like sensing changes in water temperature and salinity.

Although newer technologies involving genetics, satellite tagging and aerial counts and mapping have led to breakthroughs in whale research, they provide only snapshots of what the animals do, says behavioral ecologist and geneticist Greg O’Corry-Crowe of Florida Atlantic University in Fort Pierce. He wanted to try what he calls an “old-style natural history and behavioral observation.”

Using a remotely operated flying drone, O’Corry-Crowe and colleagues spent hours filming narwhals swimming in an island bay in the Canadian High Arctic in the summer of 2022. One recording captured three narwhals among several Arctic char (Salvelinus alpinus), chasing fish and occasionally swinging their tusks like baseball bats to stun fish before chowing down. Another video showed three narwhals following a large char, with one whale taking the lead in lightly nudging and flipping the fish with the tip or side of its tusk, altering the fish’s path.

The second recording may have shown two species that don’t regularly interact investigating one another, as little evidence implies that narwhals normally eat char, and they do most of the year’s hunting and dining in the winter, O’Corry-Crowe says. “There’s this tentativeness,” he explains. “The fish makes a dramatic movement, and even the big animal just recoils and goes whoa!” Aspects of the scene, such as the narwhals’ low-stress environment, their repeated actions with their tusks and the fact that they didn’t try to eat the fish, suggested the whales were playing.

Because of the Arctic’s harsh environment, people often think creatures residing there are constantly fighting to survive, O’Corry-Crowe says. But the new study hints that sometimes these animals have time to explore — and possibly play — during their “summer vacation.”