Canary Islands a total of five different species of marine turtle that are sighted periodically in the islands, the most common of these being the endangered loggerhead sea turtle. The other four are the green sea turtle, hawksbill sea turtle, leatherback sea turtle and Kemp's ridley sea turtle. Currently, there are no signs that any of these species breed in the islands, and so those seen in the water are usually migrating. However, it is believed that some of these species may have bred in the islands in the past, and there are records of several sightings of leatherback sea turtle on
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