Despite having a cult following among fans of obscure animals, narwhals remain an extremely mysterious creature. Until recently, scientists knew next to nothing about the hangouts, diet, and sex lives of these notoriously skittish marine mammals.
Over the past few decades, however, that's begun to change. Now, research from the American Geophysical Union has built a better understanding of the private life of narwhals by studying a pod and their seasonal voyages to the glacier-forged fjords of Greenland.
In a new study revealed at the 2018 Ocean Sciences Meeting on February 9, scientists fitted tracking devices to a pod of 15 narwhals living near the glaciers of West Greenland’s Melville Bay over a period of four years. They then paired this with environmental data about the bay to get a glimpse of the narwhals' behavior and migration habits.
Previously, it was uncertain as to why these chubby "unicorns of the sea" appear to head towards the freshwater glaciers in Greenland during the summer. It now looks like the narwhals like to congregate here because it has thick ice fronts where icebergs rarely break off, meaning it’s a calm and peaceful place to hang out.
"Narwhals like slow-moving, big walls of ice where conditions are still and serene instead of a lot of runoff and disturbance," Kristin Laidre, a scientist at the University of Washington in Seattle, who presented at the 2018 Ocean Sciences Meeting, said in a statement.
Food is also involved, as is often the case with animals. It’s thought that this area’s freshwater could shock smaller sea creatures, perhaps making them easier to hunt down and eat. Oddest of all, the narwhals might head to these glacier waters to shed their skin. After all, this is why their evolutionary cousins, the beluga whales, head towards freshwater in the summer.
Along with insights into their behavior, the researchers also looked into how these creatures are faring against the colossal environmental changes going on in their habitat.
"Arctic marine mammals are really good indicators of climate change because they are very specialized," added Laidre. "They are finely attuned to specific environmental conditions, so they are good indicator species for how the physical changes many scientists are documenting in the Arctic can reverberate throughout the ecosystem."
Until recently, scientists did not even know why they had their iconic single tooth. It had been speculated that they used it as a fertility signal, a swimming rudder, a thermal regulator, a tool for breaking ice, a weapon, a breathing organ, or a hunting tool. But a study in 2015 found that it actually has numerous nerve connections, suggesting it probably serves some kind of sensory function.
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