Leatherback sea turtle at . The leatherback turtle is a species with a cosmopolitan global range. Of all the extant sea turtle species, "D. coriacea" has the widest distribution, reaching as far north as Alaska and Norway and as far south as Cape Agulhas in Africa and the southernmost tip of New Zealand. The leatherback is found in all tropical and subtropical oceans, and its range extends well into the Arctic Circle. The three major, genetically distinct populations occur in the Atlantic, eastern Pacific, and western Pacific Oceans. While nesting beaches have been identified in the region, leatherback populations in the Indian Ocean
Varieties of Chinese increase, although there are also some sharp boundaries. However, the rate of change in mutual intelligibility varies immensely depending on region. For example, the varieties of Mandarin spoken in all three northeastern Chinese provinces are mutually intelligible, but in the province of Fujian, where Min varieties predominate, the speech of neighbouring counties or even villages may be mutually unintelligible. Classifications of Chinese varieties in the late 19th century and early 20th century were based on impressionistic criteria. They often followed river systems, which were historically the main routes of migration and communication in southern China. The first scientific classifications, based