Scientists have used drones to capture footage of what might be play behaviour from the elusive narwhal – the Arctic animal often known as the 'unicorn of the sea' because of its iconic tusk.
“I have been studying narwhal for over a decade and have always marvelled at their tusks,” says Cortney Watt, Ph.D., research scientist and team lead at Fisheries and Oceans, Canada.
Together with researchers from Florida Atlantic University’s Harbor Branch Oceanographic Institute and Inuit communities in Nunavut in Canada’s High Arctic, Watt and colleagues used drones to capture video footage of narwhals.
Narwhals (Monodon monoceros) are famous for their long tusks, which are actually one of their teeth which protrudes through their top lip. This elongated horn inspired depictions of unicorns in the Middle Ages. Experts have suggested it is used in courtship and sensing the world around them but, as these shy and elusive marine mammals are difficult to observe to find out more.
One encounter showed a group of the marine mammals chasing an Arctic char (Salvelinus alpinus) and adjusting their speed so the fish was always just in front of their tusks. This may be the first recorded evidence of play in narwhals, according to the study published in Frontiers in Marine Science
“The whale and fish movements were so closely mirrored, it was unclear at times which animal was the primary actor and who was the responder,” it says in the study.
“Our observations provide clear evidence of narwhals chasing fish and using their tusks to interact directly with the fish and to influence the fish’s behaviour,” says Greg O’Corry-Crowe, Ph.D., senior author, a research professor at FAU Harbor Branch and a National Geographic Explorer.
“Some of the interactions we saw appeared competitive in nature with one whale blocking or trying to block another whale’s access to the same target fish, while others may have been more subtle, possibly communicative and even affiliative. None appeared overtly aggressive.”
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During the study, the researchers used drones to get an aerial view of the narwhal’s behaviour.
“Narwhals are known for their ‘tusking’ behaviour, where two or more of them simultaneously raise their tusks almost vertically out of the water, crossing them in what may be a ritualistic behaviour to assess a potential opponent’s qualities or to display those qualities to potential mates,” says O’Corry-Crowe.
"But now we know that narwhal tusks have other uses, some quite unexpected, including foraging, exploration and play.”
The researchers noted 17 distinct behaviours, including the narwhals playing with their food. They also reported glaucous gulls (Larus hyperboreus) trying to steal fish from the narwhals. Although the seagulls didn’t usually have any luck, they also ruined the narwhal’s chances of catching a meal, as the fish usually escaped after being swooped on by the birds.
Most people will never see a narwhal in their lifetime so these videos give researchers an exciting glimpse into the lives of narwhals as well as helping us learn how these charismatic animals are adapting to environmental changes.
“Drones provide a unique, real-time view of their behaviour, helping scientists gather crucial data on how narwhals are responding to shifts in ice patterns, prey availability and other environmental changes,” says O’Corry-Crowe. “Such studies are key to understanding the impact of global warming on these elusive animals.”
Main image: the Arctic's iconic narwhal/O’Corry-Crowe, FAU/Watt, DFO
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