Megaherbivores are large herbivores that can exceed 1,000 kg (2,200 lb) in weight. The earliest herbivores to reach such sizes like the pareiasaurian reptiles and dinocephalian therapsids appeared in the Permian period. During most of the Mesozoic, the megaherbivore niche was largely dominated by dinosaurs up until their extinction during the Cretaceous–Paleogene extinction event. After this period, small mammalian species evolved into large herbivores in the Paleogene. As part of the Late Pleistocene megafauna extinctions, 80% of megaherbivore species became extinct, with complete extinctions occurring in Europe, Australia and the Americas. Current megaherbivores include thirteen species of elephants, rhinos, hippos, seacows, and giraffes, living in Africa, Asia, North and South America.