This is a black rhinoceros being relocated by helicopter out of its home where poachers would likely kill it. Why? Black rhino horn is valuable as "medicine." From National Geographic:
The rhino airlifts were part of WWF's Black Rhino Range Expansion Project, which has moved nearly 120 of the animals to date. In the latest effort, 19 (tranquilized) rhinos were airlifted out of their original habitat (in South Africa's Eastern Cape) and driven to a new location in Limpopo Province, about 930 miles (1,500 kilometers) away.