Large forested areas are found in central Sudan, especially in the river valleys. Among the most common trees are the hashab, talh, heglig, and several species of acacia, notably sunt, laot, and kittr. Such trees as ebony, silag, and baobab are common in the Blue Nile Valley. Ebony, mahogany, and other varieties of timber trees are found in the White Nile Basin. Other species of indigenous vegetation include cotton, papyrus, castor-oil plants, and rubber plants.
Animal life is abundant in the plains and equatorial regions of Sudan.
Elephants are numerous in the southern forests, and crocodiles and hippopotamuses abound in the rivers. Other large animals include giraffes, leopards, and lions. Monkeys, various species of tropical birds, and poisonous reptiles are also found, and insects especially mosquitoes, seroot flies, and tsetse flies infest the equatorial belt. Other ethnic groups in northern Sudan include the Beja, Jamala, and Nubian peoples. The major black ethnic groups in southern Sudan are the Azande, Dinka, Nuer, and Shilluk.