Keeping A Thick - Skinned Fellow Happy -- Mahon's morning toilet every day keeps him in a good temper - which is worth the bottle of oil, the brush, and the slight trouble involved. Mohan, the rhino at Whipsnade Zoo, is probably the most thick skinned fellow in the world - but that very thick skin causes him some trouble. If it gets too dry and hard, it cracks, and Mahon gets miserable - and a miserable rhino is not a pleasant chap to have around. Facial for the blotchy complexion of this rhino at Whipsnade Zoo, London, is a serious ritual. Each day oil is delicately applied to his cracked skin, and Mahon the rhino isn't happy until the operation is over. August 13, 1948. (Photo by Fox).