HORNS AND ANTLERS
by Junior Naturalist Frank Oberhansley
Elk antlers stimulate many questions on the part of visitors to
Yellowstone Park. Some one is forever wanting to know where he can
secure some "elk horns" or how many dead elk were necessary to provide
the "makings" for the antler house at Mammoth. After close scrutiny of
this structure, one visitor inquired as to the type of roots used in its
construction.
For the reader who is not familiar with the major facts relating to
horns and antlers the following is offered.
Only one animal in the world sheds his horns naturally and this is
the American antelope (Catelocarpidae americana). This statement will
immediately bring forth the challenge from many. "What about the deer,
elk, and moose?" The answer lies in the fact that there is a distinct
difference between horns and antlers. Horns are outgrowths of the skim
similar to nails, claws, and hair, while antlers are true bone growths,
exposed parts of the skeleton.
In the case of the elk (Cervus canadensis), the antlers are shed from
late winter to early spring. A few spike bulls were observed carrying
the antlers this year until late in May. Just what is the direct cause
of the actual shedding is unknown. Perhaps the new growth has something
to do with it, or it may be that the bony tissue attaching the antler to
the skull becomes dead and incapable of further supporting this great
weight firmly. At any rate, there is some physiological change which
causes the antler to drop at the correct season.
Almost immediately after the old antlers are shed new ones begin to
replace them. From the beginning those new antlers are very blunt.
Covered with a velvet-like tissue and richly supplied with blood vessels
and nerves, they are comparatively soft and highly sensitive. The
profuse blood supply enables the antlers to grow at an alarming rate
until by September 1 they are fully mature. During the growing state the
antlers are said to be "in the velvet" and when the growth is completed
the velvet is commonly shed by rubbing the head against a small tree and
exposing the true bony antler. Some maintain this rubbing is for the
purpose of sharpening the antlers preparatory to the fighting incident
to the mating season. Personally, I believe it to be a natural means of
relieving an irritation incident to a stricture of the nerves and blood
vessels at the base of the antler where a ring of bone solidifies and
chokes off any further supply of raw materials.
As soon as the velvet is shed the bulls are ready to fight for the
possession of a harem. Although the antlers are fully formed, they are
still green and occasionally in the initial clashes between two bulls,
the antlers may be sprung slightly so that they may become locked
tightly and death comes to both combatants.
It seems to be Nature's plan that during, the time the cows are with
calf and while the calves are using a large supply of milk, the bulls
are undergoing changes in the generative organs simultaneous with the
growth of antlers during which time the bulls and cows tend to range
separately in groups of varying numbers. The shedding of the velvet is
coincident with the mating instinct which brings the two sexes together
again in the fall.
As the season progresses the antlers become increasingly dead tissue
until the final shedding when the process is repeated.
The antelope sheds his horns in the late fall. In this case the outer
sheath only is shed leaving a bony core. At this time he may be said to
have antlers similar in structure at least to those of elk, since they
are true bone. Coarse black hair soon covers this bony core and
eventually these become cemented together with a chitinous like material
to form the true horny sheath. As stated earlier, no other animal sheds
its horns.