The Pendjari National Park () lies in north western Benin, adjoining the Arli National Park in Burkina Faso. Named for the Pendjari River, the national park is known for its wildlife and is home to some of the last populations of big game like the African forest elephant, lion, hippopotamus, African buffalo, and various antelopes in West Africa. The park is also famous for its richness in birds. The Pendjari National Park has an area of and is part of the WAP complex (W-Arli-Pendjari), a large protected area in Benin, Burkina Faso and Niger. Hills and cliffs in the Atakora range are visible from the park. In March 2009, the park was tentatively nominated for UNESCO's World Heritage Site program, and in July 2017, it was officially inscribed as a UNESCO World Heritage Site as part of a transnational extension of the WAP Complex. Ecology The rocky cliffs of the area are sparsely wooded with Burkea africana, Detarium microcarpum, Lannea acida, Sterculia setigera and Combretum ghasalense. On the deep soils of some of the summits and the Atakora escarpment, there is a greater variety of plant species with Isoberlinia doka and Afzelia africana. The Pendjari River is surrounded by forest. The park includes both the Sudanian and Guinean savannas, with areas of grassland dominated by Acacia sieberiana and Mitragyna inermis or Terminalia macroptera. The annual rainfall is approximately . The park is open year-round, although from June to November, rainfall can be heavy, and certain parts of the park may be inaccessible. Fauna and flora Mammals Pendjari National Park has a relatively large population of elephants, which was stable over the last decades and counted more than 800 individuals between 2005 and 2010. The WAP Complex's elephant population is more than 3,800, making it the largest elephant concentration in all of western Africa. The second largest species of the park is the hippopotamus. There are also large populations of several other large herbivores like African buffalo (Syncerus caffer brachyceros; c. 2,700 animals in 2000), western hartebeests (Alcelaphus buselaphus major; c. 1,500 in 2000), roan antelope (c. 2,000 in 2000), kob antelope (c. 2,600 in 2000), and warthogs. Some other antelope species like korrigum (Damaliscus lunatus korrigum), bushbuck, and reedbuck are relatively rare. Smaller bovids are the red-flanked duiker, oribi, and common duiker. Primates are represented by the olive baboon, patas monkey, and tantalus monkey. One of the rarest large predators