conflict they are silent. Animals of all kinds which habitually use
their voices utter various noises under any strong emotion, as when
enraged and preparing to fight; but this may merely be the result of
nervous excitement, which leads to the spasmodic contraction of almost
all the muscles of the body, as when a man grinds his teeth and
clenches his fists in rage or agony. No doubt stags challenge each
other to mortal combat by bellowing; but those with the more powerful
voices, unless at the same time the stronger, better-armed, and more
courageous, would not gain any advantage over their rivals.
It is possible that the roaring of the lion may be of some service to
him by striking terror into his adversary; for when enraged he likewise
erects his mane and thus instinctively tries to make himself appear as
terrible as possible. But it can hardly be supposed that the bellowing
of the stag, even if it be of service to him in this way, can have been
important enough to have led to the periodical enlargement of the
throat. Some writers suggest that the bellowing serves as a call to the
female; but the experienced observers above quoted inform me that
female deer do not search for the male, though the males search eagerly
for the females, as indeed might be expected from what we know of the
habits of other male quadrupeds. The voice of the female, on the other
hand, quickly brings to her one or more stags (3. See, for instance,
Major W. Ross King ( The Sportsman in Canada, 1866, pp. 53, 131) on
the habits of the moose and wild reindeer.), as is well known to the
hunters who in wild countries imitate her cry. If we could believe that
the male had the power to excite or allure the female by his voice, the
periodical enlargement of his vocal organs would be intelligible on the
principle of sexual selection, together with inheritance limited to the
same sex and season; but we have no evidence in favour of this view. As
the case stands, the loud voice of the stag during the breeding-season
does not seem to be of any special service to him, either during his
courtship or battles, or in any other way. But may we not believe that
the frequent use of the voice, under the strong excitement of love,
jealousy, and rage, continued during many generations, may at last have
produced an inherited effect on the vocal organs of the stag, as well
as of other male animals? This appears to me, in our present state of
knowledge, the most probable view.
The voice of the adult male gorilla is tremendous, and he is furnished
with a laryngeal sack, as is the adult male orang. (4. Owen Anatomy of
553