Data from: Paradoxical escape responses by narwhals (Monodon monoceros)

• Main Authors: Williams, Terrie M., Blackwell, Susanna B., Richter, Beau, Sinding, Mikkel-Holger S., Heide-Jørgensen, Mads Peter
• Format: Dataset
• Language: unknown
• Published: Data Archiving and Networked Services (DANS) 2018
• Subjects: Life sciences; medicine and health care; Monodon monoceros; Heart rate; narwhal; 2013-2014; swimming; diving; stroke frequency; bradycardia; marine mammal; escape; Greenland; energetics; Fear; Scoresby Sound; envir; geo; Arctic; Scoresby; East Greenland; narwhal*; Sea ice
• Online Access: https://doi.org/10.5061/dryad.4vn11

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. Heart rate, stroke frequency, and energetic costs of diving narwhalsThis file contains three pages of data related to the physiology of adult narwhals during escape and post-escape dive periods. Page 1 compares heart rate/stroke frequency relationships for dives associated with different handling periods. Page 2 includes data for minimum heart rate in relation to maximum dive depth. Page 3 provides data for the energetic cost of escape dives, post-escape dives, and transit swimming. Further details are provided in the manuscript text.Williams TM data table DRYAD.xlsx