ZOOLOGICAL SOCIETY 

 BULLETIN 



PuJ)liiihed 1)1/ the Neio York Zoological Society 



Vol.. XVI 



MAY 1912 



Number 51 



THE WIDE- HORNED WHITE MOUNTAIN SHEEP 



Btf William T. Hornaday 



RF.CEXT hunting trips to Yukon Territory 

 made by Wilson Potter and Henry Diss- 

 ton, Jr., of Philadelphia, resulted in the 

 discovery by them of the most remarkable White 

 Mountain Sheep specimens that (so far as known") 

 have come out of northwestern America. The spe- 

 cies represented is Ovis dalli, but the fact revealed 

 by the specimens is new and startling. At the last 

 moment before closing this manuscript, the Na- 

 tional Collection of Heads and Horns received, 

 as a gift from Frederic H. Osborn, of New 

 York, a nephew of President Osborn, an Ovis 

 (lain head that unmistakably belongs in the same 

 class as the Potter-Disston specimens. 



The ordinary horn architecture of the white 

 sheep, as found in Yukon Territory and eastern 

 Alaska, and also in the Kenai Peninsula, is quite 

 well known. Described in a few words, it is 

 essentially a refined and compacted version of 

 tlie standard horns of the Rocky Mountain Big- 

 Horn, with the addition of long, slender points 

 that sometimes abruptly thrust outward from 

 the face. Sportsmen call it a close spiral, be- 

 cause, instead of opening out widely from the 

 face, the middle section of the horn descends 

 almost parallel with the cheek, and not far awav. 

 Not infrequently, however, a white-sheep horn 

 of extreme length will thrust a long, slender 

 |)oint outward almost at a right angle with the 

 face. Occasionally, also, a black mountain sheep 



develops horns of great spread in proportion to 

 their length, but such cases seem to be excej)- 

 tional. The proposition that wide-spreading 

 horns constitute a distinguishing character of 

 tlie black sheep species has been strenuously 

 denied. Thus far no locality, so far as we are 

 aware, has developed a common type of widely 

 spreading horns, even of the black shee)). 



The specimens under consideration are re- 

 markable because of the fact that they represent 

 a horn type never before seen by the writer in 

 Oi'is dalli, either as a distinct local type or other- 

 wise, and also because there are so many of 

 them (from the same locality) that they compel 

 attention. Their unusual size may be mentioned 

 as a third feature of interest. 



The series of specimens consists of six mounted, 

 heads, and while they have not been all cast in 

 tile same mold, their characters are fairlv uni- 

 form. Without descending for anv distance 

 ])arallel with the cheek, these horns spread out- 

 ward, continuously, until at least four of the 

 six acquire tip-to-tij) pro|)ortions and openness 

 of sj)iral that are remarkable for Oris dalli. In 

 general terms, Mr. Potter's No. 1 is a fairlv 

 exact counterpart of a fine head of Orix karcliiii 

 in the National Collection of Heads and Horns, 

 wliich measures in length Ho inches, spread l)e- 

 twcen tips 36 inches, and in circumference 1;!] 

 inches. 



