Most of Zimbabwe is covered with savanna grassland and dotted with low masasa trees. Aloe plants are common in the drier areas, and the low-lying river valleys have baobab, acacia, and teak trees. The higher elevations have grassland and shrubs, interspersed with dense forests and patches of rain forest. Wildlife includes elephants, hippopotamuses, lions, hyenas, crocodiles, antelope, impalas, giraffes, and baboons. For the most part, wildlife is confined in Zimbabwe’s game parks, the largest of which is Hwange National Park in the west. All the major mammal species are protected, with rhinoceros, cheetah, and hartebeest -a species of African antelope being among the endangered species.