Dead whales are the largest, most energy-rich detrital particles in the ocean, typically containing >1 million grams of organic carbon in lipids and proteins. Most whales suffering natural mortality sink rapidly to the deep-sea floor. There they support a remarkable assemblage of invertebrates specializing on whale falls, with life styles and bacterial symbioses uniquely adapted to the whale-fall habitat. Diversity levels on deep-sea whale falls may exceed those at hydrothermal vents. Recent whale-sinking experiments (using animals suffering natural mortality) demonstrate that deep-sea whale falls support a succession of little known communities dominated in sequence by (1) mobile scavengers (including 3.5-m sleeper sharks), (2) opportunistic worms thriving in blubber enriched sediments, (3) worms with “roots” that burrow through the bones digesting whale oil, and (4) sulfide loving clams and mussels attaching to the outside of the bones. A newly developed radiometric dating technique indicates that large whale falls may support these specialized communities for up to 100 years. In coastal habitats, some mobile, intertidal scavengers, such as polar bears, may also obtain significant energetic benefits from whale carrion. Commercial whaling drastically reduced the occurrence of detrital whales in all marine ecosystems, and is likely to have caused substantial species extinction within the remarkable deep-sea communities dependent on whale falls. Species extinctions were likely most severe in the North Atlantic where whales were decimated in the 1800’s, and may be ongoing in the Southern Ocean and northeast Pacific, where intense whaling occurred into the 1960’s and 1970’s. Thus, by overexploiting whale populations in the surface ocean, humans may have unknowingly altered biodiversity and evolutionary novelty in major regions of the deep sea.