Narwhals are among the most stress-sensitive cetaceans, with unique physiology that makes capture and disturbance particularly harmful. Climate change is altering their Arctic habitat in ways that compound welfare risks.
Research by Terrie Williams and colleagues revealed a remarkable physiological vulnerability in narwhals: when fleeing threats, their hearts race with fear while simultaneously slowing to conserve oxygen for diving — a dangerous combination that can result in oxygen debt and prolonged recovery. This suggests that disturbance events humans may consider minor — boat approaches, net entanglement, research handling — impose severe acute welfare costs on narwhals. Climate change compounds this by reducing sea ice that narwhals use as refuge from killer whales, increasing predation stress. As shipping lanes open in the Arctic, acoustic disturbance from vessels disrupts narwhal communication, navigation, and feeding. The combined welfare burden of climate disruption, shipping noise, and predation exposure on a physiologically stress-sensitive species warrants serious attention from conservation planners.