 Temperate Asia is the eastern part of the Palearctic realm (which in turn is part of the Holarctic), and its south-eastern part belongs to the Indomalayan realm (previously called the "Oriental region").Asia shows a notable diversity of habitats, with significant variations in rainfall, altitude, topography, temperature and geological history, which is reflected in its richness of animal life.The formation of the Asian fauna began in the Mesozoic with the splitting of Laurasian supercontinent.