At the Caldwell Zoo in Tyler, Texas, we catch a mother and son rhino having a nap. The Black Rhinoceros, a native of Africa, has been hunted to near extinction for its horn. Although their population is slowly increasing, they are considered Critically Endangered, and exist mainly on animal reserves in Kenya, Tanzania, Namibia, Zambia, and South Africa.. This young rhino, Phineus, was born at the Caldwell Zoo in September, 2007.