When humans use the grasslands to graze their cattle, the grass dries out and dies. Some land then turns to desert, while other areas are vulnerable to fires that destroy the land. Overgrazing of the land, poaching and human use of precious resources has caused several savanna animals to become endangered. Black Rhino (Diceros bicornis0) The black rhino is one of the most endangered animal in the world--there were fewer than 3,200 in the world in 2001, most of which live on wildlife preserves. Even there, poachers kill them for their horns, which some people believe have medicinal value. Since the poachers make a lot of money selling the horns, these animals will continue to be hunted. African Elephant Even though it is illegal, African elephants are hunted for their tusks, their meat and skin. Loss of habitat due to human expansion also threatens the African elephant population. Most elephants in the savanna today are living on wildlife preserves, but the parks are not large enough to support the population. A recent study shows that the population of elephants has dropped by almost two-thirds or 62 percent in the past 10 years,