Narwhals have been having a moment in the last few years. These elusive “unicorns of the sea" have graduated from unappreciated Arctic animals to become meme bait, plushies and the subject of a really weird novelty song. Despite their popularity, researchers still don’t know as much about the little whales as they’d like, mainly because they live among cracks in the ice in one of the most remote and inhospitable regions in the world. But Leah Rosenbaum at ScienceNews reports that biologists were recently able to tag a population of the whales with a new type of acoustic device, getting the most intimate recordings yet of the clicks, whirs and buzzes the animals use to hunt and communicate, especially at times of the year when sunlight is scarce.
In particular, the researchers wanted to get more information on narwhal communication to provide a baseline for future research. As the Arctic warms and ice crumbles, many areas where narwhals live will be open to human activities like oil exploration, shipping and tourism. Researchers want to understand how all the human-generated noise will affect the whales.
For the new study in the journal PLoS One, researchers looked at the remote and little-studied narwhals of Scoresby Sound in eastern Greenland. Over several field seasons, they successfully tagged six narwhals, five females and one male, with a device called Acousonde. In previous studies of narwhals, researchers used underwater microphones called hydrophones, which picked up all the sounds in the ocean, but could not pinpoint individual animals, their location or what activity they were doing. Other types of satellite tags last only a few hours. The Acousonde device, however, attaches to a ridge on the narwhals back via a magnesium link. After three to eight days, the magnesium degrades, allowing the device to float to the surface where researchers can recover it.
In total, the team collected 533 hours worth of narwhal sounds from individuals known as Thora, Helge, Frida, Freya, Eistla and Balder, which they were able to pair up with GPS data. Alan Burdick at The New Yorker reports that the recordings illuminate just how the whales use sound. The beasts tend to make clicking and buzzing sounds while in the deep sea, about 700 to 2,000 feet down, and buzzed quite a bit in one particular fjord, likely using echolocation while hunting shrimp and cod. (Kate Stafford, of the University of Washington, not involved in the study, tells Rosenbaum “They’re like wet bats.”)
They made their squeaky, whistling calls when they were closer to the surface, often within 20 feet, probably to communicate with other narwhals. In some cases several narwhals were recorded calling at once during a “conference.”
The study illuminates some of the basic natural history of the whales, which researchers have had an almost impossible time trying to collect. “The inhospitable pack-ice environment that is narwhals' home for much of the year has for millennia kept them in relative isolation—even from biologists,” the lead author of the study, Susanna Blackwell of Greeneridge Sciences, said in a press release. (Greeneridge Sciences produces the acoustic tag.) “Now new amazing tools allow us to take a multi-day, virtual ride on the back of a narwhal!"
The next step will be simulating human-generated noise to see how the whales react, reports JoAnna Klein at The New York Times. Oil and gas exploration crews often use seismic air guns to search for fossil fuels under the seabed. The blasts from the guns are believed to damage the ears and internal organs of marine animals, and can prevent critters from communicating with one another. It’s possible that the narwhals, used to the incredibly loud sounds of icebergs calving into the Arctic Ocean, will just shrug off the air gun blasts. Then again, the blasts might disrupt their ability to hunt. “Maybe air gun pulses sort of sound like icebergs for a narwhal — I have no idea — but if we don’t have the data, we can’t make sound decisions to make sure that we have narwhals in the future,” Blackwell tells Klein.
And if we don’t have narwhals, then who is going to eat all our extra bagels?