Sperm whales are the largest toothed predators on Earth and possess the largest brains of any animal, facing threats from ship strikes, entanglement, and noise pollution that disrupt their complex social lives.
Sperm whale welfare deserves particular moral weight given their extraordinary cognitive capacity. The largest brains of any animal, combined with complex cultural transmission of click dialects across generations, suggests rich inner lives. Sperm whales that strand often show extended care behaviour toward distressed conspecifics. Ship strikes cause traumatic death. Entanglement in fishing gear causes drowning or exhaustion. Low-frequency military sonar has been associated with mass strandings in which whales surface rapidly and suffer decompression-like injuries. Plastic ingestion causes chronic gastrointestinal harm before death. Each of these threats is partially addressable through policy and consumer action.