Because of its size and ecological diversity, Texas supports a native fauna of about 140 species of terrestrial mammals. In addition to native mammals, some species have been introduced.
Order Marsupialia. Only one marsupial, the Virginia opossum (Didelphis virginiana), occurs in Texas. It is distributed statewide, except for some arid far-western parts of the state.
Order Insectivora. Two families of insectivores, Soricidae (shrews) and Talpidae (moles), are represented in Texas. Four species of shrew occur: two kinds of short-tailed shrew (Blarina) in East Texas, the least shrew (Cryptotis) in much of East and Central Texas, and the desert shrew (Notiosorex) in arid habitats in West Texas. Of the moles, the eastern mole (Scalopus), a species of burrowing mole, is the only one that occurs in the state. It is common over much of eastern Texas and reaches westward to the Panhandle, the eastern edge of the Llano Estacado, and Presidio County.
Order Chiroptera. Four families of bats are represented in Texas: Mormoopidae (mustached bats and allies), Phyllostomidae (leaf-nosed bats and allies), Vespertilionidae (common bats), and Molossidae (free-tailed bats). A single species of Mormoopidae, the ghost-faced bat (Mormoops), occurs in Texas and is known as far north as the southwestern and south central regions of the state. Members of the family Phyllostomidae are limited primarily to the American tropics. Three species barely reach Texas. The Mexican long-tongued bat (Choeronycteris) has been recorded once in the lower Rio Grande valley, the big long-nosed bat (Leptonycteris) is known in the Big Bend, and the hairy-legged vampire (Diphylla) has been taken but once from near Comstock. Twenty-two members of the family Vespertilionidae make up an important component of the Texas fauna. All are insectivorous. Some, such as the big brown bat (Eptesicus), are nearly statewide in distribution. Others, such as several species of the genus Myotis, have more restricted distributions. And some, such as the silver-haired bat (Lasionycteris), may be present in the state only during semiannual migrations. Four species of the free-tailed bats or Molossidae-three in the genus Tadarida and one in the genus Eumops-occur in Texas. Only one, the Brazilian free-tailed bat (T. brasiliensis), can be distributed statewide, and only in the warm months.
Order Xenarthra. Of the armadillos (Dasypodidae) and their allies, only one, the nine-banded armadillo (Dasypus novemcinctus), occurs in Texas. The armadillo ranges over most of the state, being absent only from the extreme western and southwestern parts.
Order Lagomorpha, Family Leporidae. Four species of lagomorphs are found in Texas, the most common and widespread being the black-tailed jackrabbit (Lepus californicus), which occurs over most of the state but is abundant westwardly, and the eastern cottontail (Sylvilagus floridanus), which is a common inhabitant of all but parts of the extreme southwest. Two other species of Sylvilagus are known-the desert cottontail, which occurs in upland habitats in the western half of the state, and the swamp rabbit, which occupies lowland areas in the eastern third of Texas.
Order Rodentia. This order is represented in Texas by members of the family Sciuridae (squirrels and allies), of the family Geomyidae (pocket gophers), of the family Heteromyidae (pocket mice and kangaroo rats), of the family Castoridae (beavers), of the family Cricetidae (New World mice and rats), and of the family Erethizontidae (porcupines).
Because most are diurnal, squirrels are among the best known of native rodents. In the Texas fauna there are two tree squirrels (Sciurus), the fox squirrel and the gray squirrel, native to the eastern and central parts of the state and frequently introduced westwardly, and four species of ground squirrels (Spermophilus), some of which occur in all but East Texas. Additionally, there are the unique prairie dog (Cynomys), once widely distributed in the West and still common in some areas, the antelope ground squirrel (Ammospermophilus) of the Trans-Pecos region, a chipmunk (Tamias), known only from the Guadalupe Mountains and the Sierra Diablo, and the nocturnal southern flying squirrel (Glaucomys), which occurs in the eastern third of the state.
The mounds of the pocket gophers, burrowing rodents, are typical features of the Texas landscape. Pocket gophers are common, often abundant, in favored soils; at least one type can be found anywhere in the state, but the kinds never coexist with each other. The Texas fauna includes at least five species of brown pocket gophers (Geomys), Botta's pocket gopher (Thomomys), and the yellow-faced pocket gopher (Cratogeomys).
The nocturnal pocket mice and kangaroo rats are typical of the grasslands and semiarid regions of the western and southern parts of the state. The kangaroo rats (Dipodomys), frequently seen along roadways at night, are represented by five species in Texas, the spiny pocket mouse (Liomys) by a single species that occurs only in the lower Rio Grande area, and the true pocket mouse (Perognathus) by six species, the largest of which, the spiny pocket mouse (P. hispidus), is the only heteromyid that is nearly statewide in distribution.
The Castoridae are represented in the New World only by the familiar beaver (Castor canadensis), which is known from East and Central Texas and westward along the Rio Grande and its tributaries and the Canadian River.
New World mice and rats are represented by more species native to Texas (twenty-nine) than any other mammalian family. The most conspicuous of cricetids are the semiaquatic muskrat (Ondatra zibethicus), because of its wide distribution and commercial value as a furbearer, and the wood rats (Neotoma), four species of which occur in the state (at least one of which can be found in any area), because of their frequently conspicuous "houses." The most common and widespread genus contains the white-footed mouse (Peromyscus), with nine species. Other native mice and rats include one pygmy mouse (Baiomys), two grasshopper mice (Onychomys), four harvest mice (Reithrodontomys), two rice rats (Oryzomys), the golden mouse (Ochrotomys), two cotton rats (Sigmodon), the woodland vole (Pitymys), and the Mexican vole (Microtus). The prairie vole (M. ochrogaster) once occurred in southeastern Texas, but that population is probably now extinct.
The distinctive porcupine (Erethizon dorsatum) is a characteristic mammal of the western half of Texas. It is mostly an animal of coniferous woodlands, but occupies a variety of habitats, some quite distant from forests.
Order Carnivora. Representatives of the families Canidae (coyotes, foxes, and allies), Ursidae (bears), Procyonidae (the raccoon and its allies), Mustelidae (weasels, skunks, and allies), and Felidae (cats) occur in Texas.
Six species of canids are native to Texas. One, the red wolf (Canis rufus), evidently now is extinct, and its larger relative, the gray wolf (C. lupus), once common, is represented only by an occasional straggler from Mexico in the Trans-Pecos region. The coyote (C. latrans) is common and of statewide occurrence. Two small foxes, the desert or kit fox (Vulpes macrotis) and the swift fox (V. velox), occur only in far western Texas, whereas the gray fox (Urocyon) is found nearly all across the state. The red fox (V. vulpes), a North American native that was introduced in the 1890s, now is found over most of eastern and central Texas and west to the Panhandle.
The grizzly bear (Ursus arctos) once occurred in the mountainous regions of the Trans-Pecos but was long ago extirpated. The black bear (U. americanus), once widespread, probably also is extinct in Texas, though occasional individuals still may be found in the mountains of the Trans-Pecos and in the forests of East Texas.
The raccoon (Procyon lotor), one of the most familiar and economically important of Texas carnivores, has a statewide distribution and is of common occurrence. Its smaller and less well-known relatives, the coati (Nasua narica) and ringtail (Bassariscus astutus), have more restricted distributions, the latter occurring mostly in the western and central parts of the state and the former only in the lower Rio Grande valley and Big Bend.
Eleven mustelids are known in Texas: the long-tailed weasel, mink, and black-footed ferret (Mustela), the last probably extinct; the river otter (Lutra), now limited to waterways in the eastern part of the state; the badger (Taxidea), widespread in the western two-thirds of Texas; and six skunks-two spotted species (Spilogale), two hog-nosed species (Conepatus), the hooded skunk (Mephitis macroura), and the familiar striped skunk (M. mephitis), the only species with a statewide distribution.
Of the cats, the mountain lion (Felis concolor) once was found throughout Texas but now occurs only in the Trans-Pecos mountains and as an occasional wanderer in forested East Texas. The bobcat (F. rufus) is relatively common, widespread, and valuable for its fur. The ocelot (F. pardalis) now occurs in some numbers along the lower Texas coast and probably in the Rio Grande valley, whereas the uncommon jaguarundi (F. yagouaroundi) is found only in the latter area. Two other felids, the jaguar (F. onca) and the margay (F. wiedii), evidently no longer occur in the state.
Order Artiodactyla. Representatives of four families of the order of even-toed ungulates occur in Texas: Tayassuidae (javalinas or peccaries), Cervidae (deer and their allies), Antilocapridae (the pronghorn), and Bovidae (bison and allies).
The collared Peccary (Tayassu tajacu) or javalina is the only Tayassuid in Texas. It once ranged rather broadly but now is restricted to the southwestern part of the state and the brush country of South Texas.
Two familiar members of the family Cervidae are the white-tailed deer (Odocoiluse virginianus), which has a statewide distribution in suitable brushy or wooded habitats, and the mule deer (O. hemionus), which occurs in the rough western country. Another cervid, the wapita or American elk (Cervus canadensis), has been reintroduced in the Guadalupe Mountains, where it apparently once occurred.
The pronghorn antelope, a readily recognizable species (Antilocapra americana), is found in West Texas, from the Panhandle southward to the Trans-Pecos, where it is the most common. Its habitat is relatively open rangelands. It once occurred much farther eastward.
The bison (Bison bison) once ranged over much of Texas but now occurs only in captivity (see BUFFALO). The bighorn sheep (Ovis canadensis) once occurred on the desert mountains of the Trans-Pecos, was extirpated, and now has been reintroduced in limited numbers.
Introduced Mammals. Aside from several native North American mammals mentioned above that have been introduced or reintroduced in Texas, a number of exotic species have been transported to the state by man, accidently or on purpose. Among these are four rodents-the house mouse (Mus), two species of rats (Rattus), and the nutria or coypu (Myocastor). The house mouse and rats, of Old World origin, are commensals of man; they live primarily in and around human habitations. The semiaquatic nutria, a native of southern South America, was introduced into Louisiana in the mid-1930s and has spread over most of the southeastern United States. In Texas it now occurs in aquatic habitats over much of the eastern part of the state.
Several ungulates, or hoofed mammals, have been introduced as game species. Some still occur mostly in at least semiconfinement and are not treated here, but others thrive in the wild state. The Barbary sheep (Ammotragus) was introduced in the canyon country of West Texas in the late 1950s and now occurs also in some desert mountains of the Trans-Pecos. The nilgai antelope (Boselaphus), blackbuck (Antilope), and axis deer (Cervus axis) are found in parts of Central and South Texas.