4 BULLETIN 1346, U. S. DEPAKTMENT OF AGRICULTURE 
nal numbers at not less than thirty to forty millions, and possibly 
more. 
George Bird Grinnell informed the writer that he has often talked 
about the abundance of antelope with men familiar with the western 
plains 50 years or more ago and has never met a man of experience 
Avho did not agree with him that during the middle of the last cen- 
tury antelope were far more abundant than buffalo. During the 
summer of 1879 Doctor Grinnell found them extremely abundant 
in North Park, Colo., where he saw trails made by them in travel 
from one locality to another Avorn in the hard soil to a depth of from 
8 to 10 inches, like the trails made by buffalo herds going to and 
from water or during their movements from one district to another. 
As against the many millions of pronghorns once inhabiting this 
continent a recent census, taken through the Biological Survey and 
detailed elsewhere, shows approximately 30,000 survivors. (See 
Table 1, p. 3.) 
CHARACTERISTICS OF THE AMERICAN ANTELOPE 
Horns, — The pronghorn is the only antelope in the world with 
branched or pronged horns, and has the unique characteristic among 
all hollow-horned ruminants of shedding the outer covering of the 
horns annually. Tliis takes place soon after the rut in November 
and December in the Yellowstone National Park in northern Wyo- 
ming, and elsewhere in the range of the species this time probably 
varies somewhat with latitude. 
"V^Hien the time for shedding arrives the horny sheath gradually 
loosens and becomes detached from the skin around the base and, 
following this, from the bony core within. Later the horn falls ojff, 
leaving the bony core covered with a blackish skin more or less 
overgrown Avith long, coarse hairs, Avhich afterward are gradually 
lost. A new horny nucleus develops on the tip of the bony core, 
the horny growth then extending slowly dowuAvard until it reaches 
the base. Gradually thickening and hardening, the horny material 
grows at the tip until the new horn attains its full development. 
The horns continue to grow as the animal increases in age until 
the full size is reached. 
Both sexes have horns, those on the does being smaller and slen- 
derer than on the bucks. 
Rump patch. — ^Another characteristic of these interesting animals 
is a conspicuous rump patch composed of Avhite hairs Avhich are 
longer than those elsewhere on the animaFs back. Through develop- 
ments in the skin muscles the pronghorn at times of excitement has 
the power to erect these Avhite hairs until they stand out stiffly over 
the rump, forming a great dazzlingly white rosette, like a giant 
chrysanthemum, Avhich, when the animal is dashing aAvay across 
the plains in the bright sunlight, is extraordinarily conspicuous. 
The writer has many times discovered bands of antelope running 
on the open plains Avhere but for these heliogi-aphic patches they 
would have been beyond ordinary eyesight. These long rump hairs 
lie like other hairs on the skin and give little indication of their 
strikingly conspicuous appearance until the animal suddenly throws 
them up into action. The antelope faAvns at a very early age 
