In 2013, a sperm whale washed up dead on Spain’s southern coast. In its ruptured digestive tract, scientists found an entire flattened greenhouse that once grew wintertime tomatoes, complete with plastic tarps, hoses, two flower pots, and a spray canister. The whale also contained an ice cream tub, mattress parts, a carafe, and a coat hanger. And that was just the obvious human refuse. Our toxic chemicals build up in whale blubber over years such that the concentration of pollutants in some whale bodies now far exceeds that of the water surrounding them. In whales’ vastness, the reach of humanity’s destruction is magnified — but so too is the potential of our compassion. In her genius debut book, Fathoms: The World in the Whale, writer Rebecca Giggs asks: Who are we to whales? What does it mean to pollute not just places, but animals? What can understanding our ecological crises through the perspectives of other creatures teach us about ourselves? In this episode, we speak with Giggs about the astonishing ways in which whales and humans live in each other’s wakes and the enormous power of the world’s largest mammals to expand our own moral capacity.