Deep sea whale falls are thought to be hotspots of adaptive radiation for specialized fauna. Organisms that have been observed at deep-sea whale fall sites include giant isopods, squat lobsters, polychaetes, prawns, shrimp, lobsters, hagfish, "Osedax", crabs, sea cucumbers, and sleeper sharks. New species have been discovered, including some potentially specializing in whale falls. It has been postulated that whale falls generate biodiversity by providing evolutionary stepping stones for multiple lineages to move and adapt to new environmentally-challenging habitats. Researchers estimate that 690,000 carcasses/skeletons of the nine largest whale species are in one of the four stages of succession at any one time. This estimate implies an average spacing of and as little as along migration routes. They hypothesize that this distance is short enough to allow larvae to disperse/migrate from one to another.