In North America there is a second distinct smaller species, called the coyote or prairie-wolf (Canis latrans), and perhaps the Japanese wolf (C. hodophylax) may be distinct, although, except for its smaller size and shorter legs, it is scarcely distinguishable from the common species.
The reindeer, arctic fox (Canis lagopus), hare, wolf, lemming (Myodes obensis), collar lemming (Cuniculus torquatus) and two species of voles (Arvicolae) are the most common on land.
Mustela alpina, Canis alpinus, the sable antelope (Aegocerus sibiricus), several species of mouse (Mus gregatus, M.
Admixture of Mongolian species, such as Canis corsac, Felis manul, Spermophilus dauricus, the jerboa (Dipus jaculus), two hamsters (Cricetus songarus and C. furunculus), three new voles (Arvicolae), the Tolai hare, Ogotona hare (Lagomys ogotona), Aegocerus argali, Antilope gutturosa and Equus hemionus (jighitai).
Dogs, wolves, jackals, &c., which constitute the genus Canis in its more restricted sense, foxes are best distinguished by the circumstance that in the skull the (postorbital) projection immediately behind the socket for the eye has its upper surface concave, with a raised ridge in front, in place of regularly convex.