Updated Jun 14, 2018

Elusive narwhal sounds recorded, revealing animal's behavior

Scientists tag an East Greenland narwhal to study its sounds. Photo: Susanna Blackwell/Greeneridge Sciences, Inc.

Scientists have captured the sounds made by the elusive and unusual East Greenland narwhal — whose long horn inspired various tales, including that of an evil stepmother who wove her long hair into a tusk.

Little is known about these narwhals, who live "in a very pristine environment where little is known about the adaptations of the animals that thrive in these remote regions," study author Mads Peter Heide-Jørgensen tells Axios. He says he's been working on safely capturing the whales since 1993 and on improving recording methods since 2012

After capturing six narwhals in Scoresby Sound, which is the world's largest and probably least-known fjord system, the team tagged them with special acoustic and GPS satellite instruments. They recorded 533 hours of audio, matching the sounds with their location and likely activity.

They noted three types of sounds: clicks, buzzes and calls. Calls, likely how they communicate, tend to happen closer to the surface at less than 100 meters (but often less than 7 meters). Clicks and buzzes, used as echolocation to find food, often occur between 350–650 meters below the surface.

The research team was surprised "[t]hat these whales are more specialized than we thought initially. They depend on very specific water depths in relatively small areas for feeding on a few prey species," says Mads Peter, who works for the Greenland Institute of Natural Resources.

The concern amongst many scientists is that two main climate change effects on the Arctic — warming sea temperatures and increased human and industrial activities from disappearing sea ice — could affect the small population of narwhals. These creatures rely on sound for communication, navigation and feeding.

Mads Peter says:

"Narwhals may abandon areas with increased warming and loss of their preferred prey species, but they may also avoid areas with underwater noise from seismic explorations, oil drilling, shipping, sand dredging, mining and fishery."

This research "is inspiring," says UC-Santa Cruz' Terrie Williams, who was not part of the study. She says it's important to gather more information on the potential impact of human noise:

"There are concerns that anthropogenic noises will cause changes in critical vocal behaviors of the animals — imagine not being able to locate members of your pod, or locate fish to eat.  For deep-diving cetaceans such as narwhals these sounds are vital to their survival." 

Dive deeper: Listen to rare narwhal recordings captured by the team and read the study published in PLOS ONE on Wednesday.

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Police officer in George Floyd killing arrested

A protester with a sign with George Floyd's last words. Photo: Stephen Maturen/Getty Images

Derek Chauvin, the Minneapolis police officer involved in the killing of George Floyd, was taken into custody Friday by Minnesota's Bureau of Criminal Apprehension, according to the Star Tribune's Briana Bierschbach.

The state of play: Minnesota Department of Public Safety Commissioner John Harrington said that there was no additional charging information yet, as that decision is in the jurisdiction of the Hennepin County Attorney's Office.

This is a breaking news story and will be updated.

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Illustration: Sarah Grillo/Axios

President Trump's war with Twitter is confronting social media platforms with a hard dilemma: whether to take fuller responsibility for what people say on their services, or to step back and assume a more quasi-governmental role.

The big picture: Facebook is trying to be more like a government committing to impartiality and protecting free speech and building mechanisms for arbitration. Twitter, pushed by Trump's inflammatory messages, is opting to more aggressively enforce conduct rules on its private property, like a mall owner enforcing rules inside the gates.

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