The Mustelidæ constitute one of those groups which range over the whole of the great continental areas. They may be divided into three sub-families—one, the Mustelinæ, containing the weasels, gluttons, and allied forms; a second, the Lutrinæ, containing the otters; and a third, often considered a distinct family, the Melininæ, containing the badgers, ratels, skunks, and their allies.
In the first group (Mustelinæ) the genera Martes and Putorius (13 species), range over all the Palæarctic region, and a considerable part of the Oriental, extending through India to Ceylon, and to Java and Borneo. Two species of Martes (= Mustela of Baird) occur in the United States. The weasels, forming the genus Mustela (20 species), have a still wider range, extending into tropical Africa and the Cordilleras of Peru, but not going south of the Himalayas in India. The North American species are placed in the genus Putorius by Professor Baird. An allied genus, Gymnopus (4 species), is confined to the third and fourth Oriental sub-regions. Gulo (1 species), the glutton, is an arctic animal keeping to the cold regions of Europe and Asia, and coming as far south as the great lakes in North America. Galictis (2 species), the grisons, are confined to the Neotropical region.
The Otters (Lutrinæ) range over the whole area occupied by the family. They have been subdivided into a number of groups, such as Barangia (1 species), found only in Sumatra; Lontra, containing 3 South American species; Lutra (7 species), ranging over the whole of the Palæarctic and Oriental regions; Nutria (1 species), a sea-otter confined to the west coast of America from California to Chiloe; Lutronectes (1 species), from Japan only; Aonyx (5 species), found in West and South Africa, and the third and fourth Oriental sub-regions. Hydrogale (1 species), confined to South Africa; Latax (2 species), Florida and California to Canada and British Columbia; Pteronura (1 species), Brazil and Surinam; and Enhydris (1 species), the peculiar sea-otter of California, Kamschatka and Japan. The last two are the only groups of otters, besides Lutra, admitted by Professor Carus as genera.
The Badgers and allies (Melininæ) have also a wide range, but with one exception are absent from South America. They comprise the following genera: Arctonyx (1 species), Nepal to Aracan; Meles (4 species), North Europe to Japan, and China as far south as Hongkong (Plate I., vol. i., p. 195); Taxidea (2 species), Central and Western North America to 58° N. Lat.; Mydaus (1 species), mountains of Java and Sumatra; Melivora (3 species), Tropical and South Africa and India to foot of Himalayas; Mephitis (12 species), America from Canada and British Columbia to the Straits of Magellan (Plate XX., vol. ii., p. [136]). Ictonyx (2 species), Tropical Africa to the Cape; Helictis (4 species), Nepal to Java, Formosa and Shanghai (Plate VII., vol. i. p. 331).
Fossil Mustelidæ.—Species of otter, weasel, badger, and glutton, occur in European bone caves and other Post-tertiary deposits; and in North America Galictis, now found only in the Neotropical region, and, with Mephitis, occurring in Brazilian caves.
Species of Mustela have been found in the Pliocene of France and of South America; and Lutra in the Pliocene of North America.
In the Miocene deposits of Europe several species of Mustela and Lutra have been found; with the extinct genera Taxodon, Potamotherium, and Palæomephitis; as well as Promephitis in Greece.
In the Upper Miocene of the Siwalik Hills species of Lutra and Mellivora are found, as well as the extinct genera Enhydrion and Ursitaxus.
The family appears to have been unknown in North America during the Miocene period.
Family 30.—PROCYONIDÆ. (4 Genera, 8 Species.)