The tempered equatorial climate and the well-watered and fertile soils cause, that Uganda is one of the most densely populated countries in Africa. Their population is estimated to 25 Millions people. Especially conspicuous are the many young people and children, what indicates a high birth-rate. Uganda people belong to many ethnical groups with partly very different culture and customs. More then 33 local languages are spoken in different parts of the country. The official language is English. KiSwahili is widely used too between Ugandans of different linguistic background. It's a coastal language which spread into the East African interior via the 19th-century Arab slave traders. The pygmy people was the last tribes in Uganda living according to their old traditions. They lived in the lowland rainforest at the Semuliki River and in the mountain forests on the Virunga and Bwindi mountains. After in these areas the national parks was proclaimed the pygmy people was forced to leave the forest and abandon their traditional living style.