Rogues of the Borderlands
The astabanhe or giant pronghorn is an antelope-like creature found mainly in the Pinnath Gerain and the Girithlin highlands of Eriador. They stand about 4’ tall, and are dull yellow in color. While renowned for their loud white rump, their short black horns give the astabanhéli their name. Pronghorns travel in small herds (10-100) and are inquisitive, but they are quick to flee. Movements of their white tail fur signal other astanbanhéli when there is danger or when they have taken to flight. They can travel at speeds of up to forty miles per hour and can swim quite well.
Source: Middle-Earth Roleplaying Wiki