Unicorns of the Sea Reveal Sound Activities

“Bye, Buddy. I hope you find your dad.”

“Thanks, Mr. Narwhal.”

In real life, narwhals don’t speak English, like the one bidding farewell to Will Ferrell’s character in the movie Elf. Instead, they sound more like this:

WHISTLES AUDIO CLIP

That’s an audio clip recorded by scientists last summer under the icy waters of Northwest Greenland.

“If we want to describe what animals are doing, we first better understand what sounds are telling us.”

Evgeny Podolskiy, a geophysicist at Hokkaido University in Japan. Podolskiy and his colleagues study the soundscape of glacial fjords. They are noisy places, where icebergs crash into the ocean and air bubbles fizz out of melting ice. These fjords are also home to narwhals.

The animals are sometimes called Unicorns of the Sea because of their single long spiraled tusk. And they are shy, which makes them hard to study. So Podolskiy teamed up with local Inuit hunters, who snuck up on narwhals in kayaks and captured audio.

ECHOLOCATION CLIP

That’s the sound of a narwhal looking for food using echolocation, like a dolphin or a bat.

TERMINAL BUZZ CLIP

And that’s a narwhal closing in on its prey, which it vacuums up into its toothless mouth.

“It starts sounding like, to my ear, like a chainsaw or something. Crrk. Crrk. Crrk. Crrk. It’s so many little clicks that we cannot even distinguish them. And this is recognized as foraging-related sound, used also by other animals, for example other dolphinoids or bats, they do the same trick. Because when they approach the target, the prey, which is for narwhals Arctic Cod or Greenland Halibut, they want to update their knowledge about the position of the target more frequently, because they target it moving. And they need to suck it in. That’s why this interval is getting shorter. And we even by using some simple assumptions in the equation can know how far the animal is from the target.”

The whistles you heard earlier are thought to be social calls, individuals communicating with other narwhals. The researchers reported these observations in the Journal of Geophysical Research-Oceans. [Evgeny A. Podolskiy and Shin Sugiyama, Soundscape of a Narwhal Summering Ground in a Glacier Fjord (Inglefield Bredning, Greenland)]

“There are still sounds that we don’t know what do they mean and there are several like this.”

Podolskiy says that listening to narwhals is a first step toward understanding this mysterious whale, and how it will cope as climate change, shipping and other human activities alter its Arctic home.

“There are all these things taking place right now in the region which will affect somehow these animals. But we have no clue even about the state or the previous state of these animals. So if we want to learn what’s going to happen we better start now…and I hope this is where sound monitoring can help us to learn more about these still mysterious creatures.”

—Julia Rosen

(The above text is a transcript of this podcast)



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