The deep ocean is one of the most impoverished biomes on the planet. It encompasses more area than all of the world’s land biomes combined but exists hundreds or even thousands of kilometers away from the nearest solar ray, a lightless void punctuated almost entirely by the wispy phosphorescence of the creatures within it. Such light cannot sustain an ecosystem, for the energy that powers it comes from within that very ecosystem. Nearly all of the resources available to the creatures that call the deep ocean home fall from above, nutritious plankton remains forming the dense sludge called “marine snow” that coats much of the seafloor. There is productivity at the seafloor, involving chemical reactions at geologic sites called hydrothermal vents, and these locations occupy an outsized portion of the public imagination. But there is another deep-ocean ecosystem that is no less fascinating for its obscurity, and is proving to be instrumental to the persistence of hydrothermal vent life: the whalefall.