The endemic gelada (Theropithecus gelada), sometimes called the bleeding-heart monkey or the gelada baboon, is a species of Old World monkey found only in the Ethiopian Highlands, with large populations in the Simien Mountains. These baboon-size animals are the world's most terrestrial primates — except for humans. It is the last surviving species of ancient grazing primates, Theropithecus, that was once numerous. The gelada is easily recognisable by the patches of hairless skin on its chest, which turns crimson when females are in fertile.