Sperm whales have the largest brains of any animal on Earth and complex clan-based social cultures. Military sonar and plastic ingestion are significant welfare threats to this remarkable species.
Sperm whale welfare is underscored by the extraordinary cognitive complexity of these animals. With the largest brains of any creature on Earth, complex cultural traditions transmitted across generations, and what researchers describe as grief behaviors when group members die, sperm whales have an unusually strong claim on moral consideration. Military sonar causes behavioral disruption and has been associated with strandings in which whales appear to surface too rapidly, suffering fatal decompression-like injuries. Plastic pollution filling the stomachs of stranded whales illustrates how human waste causes prolonged suffering in individually identifiable animals with rich social lives.