This large buck nyala was on the grounds at Bonamanzi our last afternoon there. He was so intent on eating a large, hard, green fruit that we were able to approach so close, we could not digiscope him.
He would raise his head and let the fruit roll back into this throat, then he would chew on it with his back teeth. The sounds he made while doing this were somewhat akin to sounds I heard in my freshman year dorm, after my fellow scholars had had too much to drink. Transcribing this sound for a field guide to the sounds of foraging African mammals (or chundering American collegians) it would be roughly thus: Arrglrglrggrgahrrrraaatchhhhh!
After about five minutes the buck had broken open the hard fruit and gobbled it down in a few quick bites.