Indricotheriinae is a subfamily of Hyracodontidae, a group of long-limbed, hornless rhinoceroses convergently similar to the sauropod dinosaurs that evolved in the Eocene epoch and continued through to the early Miocene. The earlier hyracodontid species, such as Hyracodon were modest-sized, fast-running, lightly built animals with little similarity to modern rhinos. However, during the late Eocene and early Oligocene, the indricotherines evolved, and quickly grew to huge sizes. They flourished in the rainforests of a coastal region that became Kazakhstan, Pakistan, and southwest China, and lived further inland throughout central Asia as well.