TY - JOUR

T1 - Paradoxical escape responses by narwhals (Monodon monoceros)

AU - Williams, Terrie M.

AU - Blackwell, Susanna B.

AU - Richter, Beau

AU - Sinding, Mikkel Holger Strander

AU - Heide-Jørgensen, Mads Peter

PY - 2017/12/8

Y1 - 2017/12/8

N2 - Until recent declines in Arctic sea ice levels, narwhals (Monodon monoceros) have lived in relative isolation from human perturbation and sustained predation pressures. The resulting naïvety has made this cryptic, deep-diving cetacean highly susceptible to disturbance, although quantifiable effects have been lacking. We deployed a submersible, animal-borne electrocardiograph-accelerometer-depth recorder to monitor physiological and behavioral responses of East Greenland narwhals after release from net entanglement and stranding. Escaping narwhals displayed a paradoxical cardiovascular down-regulation (extreme bradycardia with heart rate ≤4 beats per minute) superimposed on exercise up-regulation (stroke frequency >25 strokes per minute and energetic costs three to six times the resting rate of energy expenditure) that rapidly depleted onboard oxygen stores. We attribute this unusual reaction to opposing cardiovascular signals—from diving, exercise, and neurocognitive fear responses—that challenge physiological homeostasis.

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

UR - http://www.scopus.com/inward/record.url?scp=85037626845&partnerID=8YFLogxK

U2 - 10.1126/science.aao2740

DO - 10.1126/science.aao2740

M3 - Journal article

C2 - 29217577

AN - SCOPUS:85037626845

VL - 358

SP - 1328

EP - 1331

JO - Science

JF - Science

SN - 0036-8075

IS - 6368

ER -