M.P. Heide-Jorgensen

You might think you're bad at handling stress, but trust us, the narwhal is much worse. The marine creature, affectionately nicknamed the "unicorn of the sea", might just be the least cool-headed animal on the planet. 

Mammals will usually react in one of two ways when they sense a threat. Firstly, they might experience a jolt of adrenaline, which spurs on a fight or flight response. On a physical level, the animal might notice an elevated heart rate, they'll start to breathe faster, and their metabolism will speed up as their body prepares for exercise. On the other hand, their heartbeat might slow, their respiration rate might drop, their metabolism might stall, and the animal "plays dead". This is called a cardiac freeze. 

Theoretically, these two reactions cannot occur at the same time. Physiologically, it is impossible. Except that in the case of the East Greenland narwhal, they do.

An international team of scientists recorded the physiological and behavioral responses of nine stranded or captured narwhals immediately after their release and discovered that following a momentary period of disorientation, the animals displayed a flight and a freeze response. 

"The narwhals exhibited both a downregulated heartbeat (characteristic of a "freeze" response) as well as an upregulated swimming stroke speed (characteristic of "flight")," the study authors explained in a statement.

This completely contradicts what the researchers expected to find. That is, that a cetacean built for deep-sea diving like the narwhal freezes in stressful situations – a response that would allow the animal to conserve oxygen while remaining deeply submerged. In contrast, the narwhal's freeze and flight response is hugely inefficient energy-wise. According to the scientists' calculations, the porpoises used up almost all their oxygen supply on the escape dive, putting them in an extremely vulnerable situation.

While narwhals have been able to escape the dangers of human interference for centuries thanks to their Arctic habitat, rising sea levels and melting ice caps are changing that. Narwhals, like many Arctic creatures, are increasingly vulnerable to man-made disturbances like shipping vessels and ocean noise, which could prove especially problematic given their unusual stress response.

 

 

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