The Niokolo Koba national park (Parc National du Niokolo Koba - PNNK) is the largest and oldest national park in Senegal lying in its south-eastern part between 12°30‘-13°20‘N and 18°30‘-13°42‘W. It was established in 1954 as the last refuge for large West African fauna in Senegal. The original area of 260 000 ha has been extended to 913 000 ha. In 1981 the Niokolo Koba national park was proclaimed a Reserve of Biosphere in the framework of the UNESCO, “Man and Biosphere” programme and put on the World Heritage List. Its southern border links up to the neighbouring Badiar national park in the Guinea making up the Niokolo – Badiar international ecological complex and biocorridor. The national park’s relief is, on the whole, flat; only in the south eastern part do the foothills of the nearby Guinean Fouta Djalon mountains rise. The average height above sea level is 100 – 150 m, the highest point is the table-top mountain Assirik with an elevation of 311 m. The basic types of soils are poorly developed tropical red soils, which in areas with increased iron contents transform into a hard armour of ferrolateritic crusts, which are either entirely exposed or have a thin layer of grey silt. This armouring is called a bowal in the local language of fulbe (peuhl). In the river valleys and depressions alluvial and hydromorphic soils have developed enabling dense and thick vegetation to form. Climatically the national park falls under the Sudanese and transitional sub-Guinean areas with rainfall being 900 – 1200 mm annually. There are two main seasons: the dry season, lasting from November to June, and the rainy season from July to October. In the peak of the dry season temperatures reach 45 °C. The largest river is the Gambia, a huge flow with high steep banks overgrown with gallery forests. In the dry period the Gambia can be forded but after the first rains the river gains strength and its level can rise by up to 10 metres. Smaller, but no less significant, rivers in the park are the right hand tributaries to the Gambia the Niokolo Koba and Koulountou (Leroux 1983; Mbow 1995; Vieillefon 1971).