Stressed-Out Narwhals Don’t Know Whether to Freeze or Flee, Scientists Find
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Narwhals – the unicorns of the ocean – show a weird fear response after appearing entangled in nets. Scientists say this unusual a reaction to human-induced strain might restrict blood circulation to the brain and keep the whales addled.
The narwhals swim hard and dive deep to escape after released from a net, but concurrently their heart rates dramatically plummet, according to a newly published report in Research. It’s nearly like they are simultaneously seeking to freeze and flee.
“This is a unique reaction to a unique kind of threat,” says Terrie Williams, a good researcher at the University of California, Santa Cruz. “I don’t assume that this is the normal response when the family pets are becoming pursued by a killer whale.”
Man narwhals have a distinctive prolonged, spiral tusk, and these elusive creatures live method up north in the Arctic. They aren’t simple to study, as they live much of their lives encircled by darkness and ice. But scientists sometimes monitor their movements by catching them with nets and tagging them in the summertime, when the whales happen to be more accessible.
Williams and her co-workers recently traveled to waters off the east coastline of Greenland to attire narwhals with technology that lets experts monitor the marine mammals’ heart rates, swimming movements and other data.
“This is the first-time that there’s been a good long-term record in an EKG for a good crazy cetacean,” says Williams, who has used related monitors in dolphins and seals. “I have no idea that there’s anything that can compare with it.”
In the primary dives after the narwhals were produced from nets, she says, their heart rates dropped from 60 beats a minute to three or four beats a minute. This lasted for 10 minutes or so.
“And I’d under no circumstances seen that in any animal that I’ve ever recorded a heartrate for,” she says. “In order that was the primary clue that people were searching at something very different here.”
What’s more, the whales were swimming rapidly during this time period. “They were exercising as fast as a narwhal exercises,” Williams says. “They were swimming continuously. They’re trying to accomplish a flight response superimposed on a down-regulation-type freeze response. And I hadn’t seen that before.”
It creates her wonder how the whales can possibly get enough oxygen with their brains. And she as well wonders if this might have got any relevance to mystical beachings of additional deep-diving whales.
Kristin Laidre, a research scientist at the Polar Research Center at the University of Washington who has studied narwhals, says this is “a really interesting paper that delivers a new physiological position on the vulnerability of narwhals to anthropogenic disturbance in the Arctic.”
The loss of sea ice in the Arctic, Laidre notes, means big changes in the ecosystem, and also a sudden interest in more industrial production, resource extraction and fresh shipping routes. “All of those factors mean disturbance for narwhals,” she says. “To my knowledge, this is actually the first time we’ve quantified physiological disturbance results on narwhals. So it is important data.”
Because narwhals have lived a good life much north, surrounded by dense sea ice, they have been relatively insulated from man activity. “Any kind of disturbance,” Laidre says, “will probably be a pretty new, potentially very disruptive point for a species that’s existed in an environment like that for so long.”