Southern dispersal, also known as the great coastal migration or rapid coastal settlement, was an early human migration along the southern coastal route, from the Arabian Peninsula via Persia and India to Southeast Asia and Oceania, with later descendants of those migrations eventually colonizing the rest of Eastern Eurasia and the Americas.
According to this thesis, the dispersal was possible thanks to the development of a multipurpose subsistence strategy, based on the collection of organisms, fish, crustaceans, molluscs, algae, which are part of the biotic communities of the intertidal zone, the transition ecosystem between land and sea between the upper limit of high tides and the lower limit of low tides, i.e. organisms left behind by the waters which retreat during ebb tide, and which people could harvest from the ground and reefs left unsubmerged or in shallow water at low tide. - In support of this hypothesis there are the remains found on an ancient Pleistocene reef, now emerged, near the locality of Abdur in Eritrea. Its rocks are the result of the compaction of marine debris about 125,000 years ago and contain fossil remains of a complex biotic community of the coast of the time: large colonies of corals, oyster shells, large clams and other bivalve molluscs, gastropods and echinoderms. A group of geologists and paleontologists found many blades and tools made of quartz, obsidian and other fine volcanic stone, mixed with the remains of shells. This would prove that over 100,000 years ago human populations of Homo sapiens exploited the intertidal zone for food purposes.