Paradoxical escape responses by narwhals (Monodon monoceros)

摘要: Until recent declines in Arctic sea ice levels, narwhals ( Monodon monoceros ) have lived relative isolation from human perturbation and sustained predation pressures. The resulting naivety has made this cryptic, deep-diving cetacean highly susceptible to disturbance, although quantifiable effects been lacking. We deployed a submersible, animal-borne electrocardiograph-accelerometer-depth recorder monitor physiological behavioral responses of East Greenland after release net entanglement stranding. Escaping displayed paradoxical cardiovascular down-regulation (extreme bradycardia with heart rate ≤4 beats per minute) superimposed on exercise up-regulation (stroke frequency >25 strokes minute energetic costs three six times the resting energy expenditure) that rapidly depleted onboard oxygen stores. attribute unusual reaction opposing signals—from diving, exercise, neurocognitive fear responses—that challenge homeostasis.