Despite its name, the waterbuck is not truly aquatic nor as much at home in water and swamps as is the sitatunga or lechwe. It does, however, take refuge there to escape predators.
The waterbuck is a large, robust animal; males are generally about 25 percent larger than the females. Waterbucks have large, rounded ears and white patches above the eyes, around the nose and mouth and on the throat. Only the males have horns, which are prominently ringed and as long as 40 inches. The horns are widely spaced and curve gracefully back and up. They are sometimes used with lethal results when males fight one another over territories.
The waterbuck has a shaggy brown-gray coat that emits a smelly, oily secretion thought to be for waterproofing. In East Africa two types occur, the common waterbuck and the defassa waterbuck, distinguished only by the white pattern on the rump. The common waterbuck has a conspicuous white ring encircling a dark rump, while the defassa has wide white patches on either side of the rump. Only male waterbucks have horns.