The discovery of Kennewick Man, along with other ancient skeletons, has furthered scientific debate over the exact origin and history of early Native American people. One hypothesis holds that a single source of migration occurred, consisting of hunters and gatherers following large herds of game who wandered across the Bering land bridge. An alternative hypothesis is that more than one source population was involved in migration immediately following the Last Glacial Maximum (LGM), which occurred ~22k to ~18k years BP, and that the land migration through Beringia was either preceded by or roughly synchronous with a waterborne migration from coastal Asia.