FIELD COLUMBIAN MUSEUM.
PLATE XXXV, ZOOLOGY.
OVIS C. MEXICANA.
U. S. Nat. Mus. Coll.
Date 1904
Source http://www.flickr.com/photos/biodivlibrary/6969287330
Author Field Columbian Museum.; Field Museum of Natural History.
Full title Publication. Field Columbian Museum.
Flickr sets The land and sea mammals of Middle America and the West Indies. v.4:pt.1(1904)
Source: https://commons.wikimedia.org/wiki/File:Publication_(Plate_XXXV)_(6969287330).jpg

The bighorn sheep (Ovis canadensis) is a species of sheep native to North America named for its large horns. Bighorn sheep are named for the large, curved horns borne by the rams (males). Ewes (females) also have horns, but they are shorter with less curvature.