Fauna of Australia are farmed for their meat and leather. Freshwater crocodiles, found only in northern Australia, are not considered dangerous to humans. The Australian coast is visited by six species of sea turtle: the flatback, green sea, hawksbill, olive ridley, loggerhead and the leatherback sea turtles; all are protected in Australian waters. There are 35 species of Australian freshwater turtles from eight genera of the family Chelidae. The pig-nosed turtle is the only Australian turtle not of that family. Australia is the only continent without any living species of land tortoise. Australia is the only continent where venomous snakes outnumber their non-venomous
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