Cetaceans arose from terrestrial ancestors 50 million years ago, in large part to exploit marine food resources. They rapidly adapted to coastal and pelagic habitats with striking changes in feeding behavior, ecology, and anatomy, evolving various foraging methods from bulk filtration to suction and cooperative hunting. In this way, cetaceans have become the largest animals that ever lived, and among the most socially intelligent. Unfortunately, the feeding methods that have served cetaceans well for so long now get them into trouble with human-created environmental problems, particularly ingestion of plastics and oil, entanglement in fishing gear, and foraging in regions with high risk of ship strikes and pollution (including sound pollution). Can resourceful cetaceans continue to adapt to changing environments, and can people likewise learn to reduce our encroachment on marine ecosystems?