The tusks of the lower jaw are very long and sharp, but the upper ones instead of growing downwards in the usual way are completely reversed, growing upwards out of bony sockets through the skin on each side of the snout, curving backwards to near the eyes, and in old animals often reaching eight or ten inches in length.

It is difficult to understand what can be the use of these extraordinary horn-like teeth.
Some of the old writers supposed that they served as hooks, by which the creature could rest its head on a branch.

But the way in which they usually diverge just over and in front of the eye has suggested the more probable idea, that they serve to guard these organs from thorns and spines, while hunting for fallen fruits among the tangled thickets of rattans and other spiny plants.

Even this, however, is not satisfactory, for the female, who must seek her food in the same way, does not possess them.

I should be inclined to believe rather, that these tusks were once useful, and were then worn down as fast as they grew; but that changed conditions of life have rendered them unnecessary, and they now develop into a monstrous form, just as the incisors of the Beaver or Rabbit will go on growing, if the opposite teeth do not wear them away.