This unspoilt wilderness is rich in flora and fauna, and contains a wide variety of animals that includes Greater and Lesser Kudu, roan and sable antelopes, which are rarely seen in most other game parks especially in Northern Tanzania. Ruaha National Park is famous for its herds of elephant and buffaloes. The Ruaha River, which plays an important role in the ecosystem of the park, provides sanctuary to a large number of hippos and crocodiles. During the dry season the river attracts great quantities of game including lions, leopard, hunting or wild dog, impala, waterbuck, warthog, giraffe, and elands. In the plains ostriches, cheetahs and Grants Gazelles can be seen. The park is rich in bird life throughout the year, with over 450 bird species recorded. The best time for game viewing is during the dry season, from May to December. During the wet months from January to April some tracks become impassable.