Vulpes macrotis

Abstract

Vulpes macrotis can be differentiated from other North American foxes by a number of criteria. Compared with the red fox (V. vulpes), the kit fox is always smaller, with most linear measurements averaging about 25% less than comparable measurements of the red fox (Hall, 1946). The legs and feet of V. macrotis are whitish or about the same color as the body, and the tail is black-tipped (figure 1); red foxes have black legs and feet and a white-tipped tail. Kit foxes lack the prominent band of coarse black hairs (the "mane" of Seton, 1923) which runs dorsally down the tail of the gray fox (Urocyon cinereoargenteus), and the tail of the gray fox is somewhat triangular in cross section while the tail of V. macrotis is round. Vulpes macrotis closely resembles V. velox in appearance and habits. The two forms may be separated by the following external characteristics (Armstrong, 1972; Thornton and Creel, 1975): 1) ears >75 mm from the notch in macrotis, <75 mm in velox; 2) ear bases set close to the midline of the skull in macrotis, widely spaced in velox (a frontal-view sketch of the two forms is provided by Thornton and Creel, 1975); 3) the head of macrotis is comparatively broader between the eyes and narrower in the snout than that of velox. The eyes of macrotis are described by Thornton and Creel (1975) as characteristically slit-like, velox eyes being more open and rounded. However, this trait varies with individuals in the red fox and may not be reliable in this case either. In a sample of five macrotis and eight velox, the tail of macrotis was significantly longer, averaging 62% of body length compared with 52% in velox (Thornton and Creel, 1975:131). Kit foxes superficially resemble a number of Old World desert foxes, which have large ears, small bodies, and light pelage color. The corsac fox (Vulpes corsac), found in the steppes and deserts of Central Asia, is about the same size as V. macrotis with long, slender legs and long ears. Its coat is a reddish-gray or reddish-brown, and the tip of the tail is weakly brown or black. Ruppell's fox (V. ruppelli), which is widely distributed in North Africa and the Near East, is slightly smaller than V. corsac, with a reddish-gray agouti coat and a reddish-orange stripe extending from the back of the neck to the tail. The tail is white-tipped. Ruppell's fox has a 2N number of 40 (Chiarelli, 1975). The pale sand fox (V. pallida) of subsaharan Africa has thin, short, sandycolored fur. The ears are smaller proportionately than those of other desert foxes, and are rounded at the tips (Bueler, 1973). The 2N number is 38 (Chiarelli, 1975). Vulpes chama, the Cape fox, and Fennecus zerda, the fennec, can be distinguished from V. macrotis by size. The Cape fox, found in southern and southwestern Africa, is rather large, weighing 3.5 to 4.5 kg and measuring as much as one meter in total length. The back is silvery in color, and the tip of the tail is black. The fennec is the smallest species of the Canidae, standing only about 200 mm at the shoulder and weighing about 1.4 kg. The ears are enormous, very broad at the base and measuring 100 to 150 mm in length. The pelage is pale and the tail is black-tipped. The cranium is broad and smooth, the dentition weak, and the bullae exceedingly large and inflated (Bueler, 1973; Clutton-Brock et al., 1976). Fennecs have a 2N number of 64 (Chiarelli, 1975).