The Nwaswitsontso River runs virtually entirely within the Park, so does not get interfered with by humans. Interesting then, compared with others. Anyway, it is the lack of grass that is obviously the problem! I think they try and eat other plants, but are simply not capable of browsing, for example. here is a video of a dying one chewing a bush in March...

http://lowvelder.co.za/video_of_the_day ... rwildtuin/