 During the long dry season, many trees lose their leaves and the predominantly annual grasses die.The Sahel was formerly home to large populations of grazing mammals, including the scimitar-horned oryx "(Oryx dammah)", dama gazelle "(Gazella dama)", Dorcas gazelle "(Gazella dorcas)", red-fronted gazelle "(Gazella rufifrons)", the giant prehistoric buffalo "(Pelorovis)" and Bubal hartebeest "(Alcelaphus busephalus buselaphus)", along with large predators like the African wild dog "(Lycaon pictus)", the Northwest African cheetah "(Acinonyx jubatus hecki)", the Northeast African cheetah "(Acinonyx jubatus soemmeringii)", the lion "(Panthera leo)".The larger species have been greatly reduced in number by over-hunting and competition with livestock, and several species are vulnerable (Dorcas gazelle, cheetah, lion and red-fronted gazelle), endangered (Dama gazelle and African wild dog), or extinct (the Scimitar-horned oryx is probably extinct in the wild, and both "Pelorovis" and the Bubal hartebeest are now extinct).