Ermine
Plates [5], [6], [7], [12], [13] and [14]
Mustela erminea olympica Hall, Journ. Mamm., 26:81, February 27, 1945; Hall, Journ. Mamm., 26:181, July 19, 1945.
Mustela rixosa, Svihla and Svihla, Murrelet, 13:24, January, 1932.
Mustela rixosa rixosa, Svihla and Svihla, Murrelet, 14:39, May, 1933.
Type.—Male, adult, skull and skin; no. 90738, U. S. Nat. Mus., Biol. Surv. Coll.; near head of Soleduc River, 4500 ft., Olympic Mountains, Clallam County, Washington; April 28, 1897; obtained by Vernon Bailey, original no. 6213.
The skin is well prepared and in good condition. The skull (plates [5]-[7]) is unbroken and the teeth all are present and entire.
Range.—Olympic Peninsula, Washington, south to Olympia. See figures [25], [27] on pages 95, 149.
Characters for ready recognition.—Differs from M. e. anguinae, in males, by lesser average size, hind foot ordinarily less than 33.4, and interorbital breadth ordinarily less than 8.5, in females by smaller size, total length less than 235, tail less than 65, hind foot less than 27.5, basilar length less than 30.2; from M. e. fallenda, in males, by length of hind foot less than 33, black tip of tail less than 36.5, weight of skull less than 1.2 grams, basilar length less than 33.5, in females length of hind foot less than 25.5, weight of skull less than 0.6 grams, basilar length less than 28.4; from M. e. streatori by smaller size, in males hind foot less than 33.0, basilar length ordinarily less than 32.5, in females by hind foot ordinarily not longer than 24, by breadth of rostrum less than 8.6, depth of braincase at posterior border of upper molars less than 7.6.
Description.—Size.—Male: Twelve individuals of adult proportions yield average and extreme measurements as follows: Total length, 243 (205-269); length of tail, 65 (60-74); length of hind foot, 31 (29-32).
Female: Corresponding measurements of six females are: 196 (188-208), 52 (45-60?), 23.4 (22.7-24.0). An adult weighs 30 grams.
Color.—As described in Mustela erminea streatori except that least width of color of underparts averaging, in 12 males of adult proportions, 5 (0-11) per cent of greatest width of color of upper parts. Black tip of tail averaging, in same series, 26 (20-35) mm., which is 40 (31-58) per cent (average the same as in streatori) of length of tail-vertebrae.
Skull.—Male (based on 5 adults): See measurements and plates [5]-[7]. As described in Mustela erminea richardsonii except that: Weight, 1.0 (0.9-1.1) grams; basilar length, 31.8 (30.6-32.5); length of tooth-rows more or less than (about equal to) length of tympanic bulla.
Female (illustrated by 3 adults): See measurements and plates [12]-[14]. As described in Mustela erminea richardsonii except that: Weight, 0.55 (0.52-0.58) grams; basilar length, 27.1 (26.7-27.5); breadth of rostrum more than 30 per cent of basilar length.
In comparison with streatori, skulls of corresponding sex average smaller in every measurement taken with no overlap in most of those of females. Exception is to be made for the inner lobe of M1 in males where the size is the same. By weight males are smaller by 10 per cent and females by 14 per cent. In relation to other parts of the skull the tympanic bullae are narrower and in females they are shorter as well. Comparison with anguinae and fallenda has been made in the accounts of those subspecies.
Remarks.—The smaller size, especially of females, is the principal feature distinguishing this race from streatori. On the basis of available data the female of olympica is smaller than that of any other race and hence is the smallest adult weasel of the species erminea, in either the Old World or in America.
Intergradation with streatori is indicated by specimens from the southern end of Puget Sound. These specimens are intermediate in size between typical examples of the two races concerned.
The color of the upper parts is uniform and the color pattern varies less than in geographically adjoining races. The white color of the underparts is restricted to a thin line on the abdominal region, but widens out posteriorly in the inguinal region and anteriorly over the pectoral region, throat, chin and lower lips. The upper lips are brown. The brown of the upper parts extends around in front of each foreleg, the two brown areas not quite meeting on the lower throat. The above description applies to each of the 19 specimens examined with regard to these details. Every specimen seen in the winter coat was brown, not white.