their full dimensions until rather late in life, they will have tended,
in accordance with the law often indicated, to transmit their
characters to their male offspring alone; and thus the great inequality
in size between the sexes of the Scotch deer-hound may probably be
accounted for.
[Fig. 65. Head of Common wild boar, in prime of life (from Brehm).]
The males of some few quadrupeds possess organs or parts developed
solely as a means of defence against the attacks of other males. Some
kinds of deer use, as we have seen, the upper branches of their horns
chiefly or exclusively for defending themselves; and the Oryx antelope,
as I am informed by Mr. Bartlett, fences most skilfully with his long,
gently curved horns; but these are likewise used as organs of offence.
The same observer remarks that rhinoceroses in fighting, parry each
other s sidelong blows with their horns, which clatter loudly together,
as do the tusks of boars. Although wild boars fight desperately, they
seldom, according to Brehm, receive fatal wounds, as the blows fall on
each other s tusks, or on the layer of gristly skin covering the
shoulder, called by the German hunters, the shield; and here we have a
part specially modified for defence. With boars in the prime of life
(Fig. 65) the tusks in the lower jaw are used for fighting, but they
become in old age, as Brehm states, so much curved inwards and upwards
over the snout that they can no longer be used in this way. They may,
however, still serve, and even more effectively, as a means of defence.
In compensation for the loss of the lower tusks as weapons of offence,
those in the upper jaw, which always project a little laterally,
increase in old age so much in length and curve so much upwards that
they can be used for attack. Nevertheless, an old boar is not so
dangerous to man as one at the age of six or seven years. (39. Brehm,
Thierleben, B. ii. ss. 729-732.)
[Fig. 66. Skull of the Babirusa Pig (from Wallace s Malay
Archipelago ).]
In the full-grown male Babirusa pig of Celebes (Fig. 66), the lower
tusks are formidable weapons, like those of the European boar in the
prime of life, whilst the upper tusks are so long and have their points
so much curled inwards, sometimes even touching the forehead, that they
are utterly useless as weapons of attack. They more nearly resemble
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