Sperm whales are the world's largest toothed predators, undertaking extraordinary dives that demand unique physiological adaptations threatened by entanglement in deep-set fishing gear.
Entangled sperm whales experience exhaustion from fighting gear, propeller strikes when gear attached to surface buoys, and eventual drowning if unable to surface. Noise pollution from seismic surveys and military sonar disrupts echolocation, communication and foraging success. Ingestion of plastic bags and debris — mistaken for squid — causes intestinal blockage and starvation. The welfare burden is compounded by the species' complex matrilineal social structure in which deaths disrupt multi-generational knowledge transmission.