Extinct rhinos include a variety of forms, the most
spectacular being _Baluchitherium_ from the Oligocene of
Asia, which is the largest known land mammal. Its body, 18
feet high at the shoulder and carried on massive limbs,
allowed the 4-foot-long head to browse on the higher branches
of trees. Though not as enormous, the titanotheres of the
early Tertiary were also large perissodactyls, _Brontotherium_
of the Oligocene being 8 feet high at the shoulder.
[ Prehistoric Animals, by Barry Cox ]