Narwhals are among the most specialized and least studied Arctic marine mammals, with their welfare acutely threatened by climate change that transforms their sea ice habitat and disrupts their prey.
Narwhals have evolved in one of Earth's most extreme environments and are exquisitely sensitive to disturbance. Research documenting their physiological stress response to capture - heart rates spiking to over 200 beats per minute while they simultaneously hold their breath from fright - reveals the intensity of their fear response. This paradoxical response (high heart rate plus breath-holding) restricts blood flow in ways that can cause cardiac stress. Climate change is fundamentally reorganizing the Arctic ecosystem on which narwhals depend: sea ice retreat opens their wintering areas to ship traffic causing noise pollution and collision risk, brings killer whales into formerly ice-protected areas, and disrupts the distribution of their prey. Each of these changes imposes welfare costs on individual narwhals.