| Arizona cotton rat | |
|---|---|
 | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Rodentia |
| Family: | Cricetidae |
| Subfamily: | Sigmodontinae |
| Genus: | Sigmodon |
| Species: | S. arizonae |
| Binomial name | |
| Sigmodon arizonae Mearns, 1890 | |
The Arizona cotton rat or Colorado River cotton rat (Sigmodon arizonae) is a species of rodent in the family Cricetidae. It is found in Mexico and the United States.
The Arizona cotton rat has a typical rat-like appearance, and is sufficiently similar to the hispid cotton rat that it was considered to be part of the same species until 1970, when genetic analysis confirmed its distinct nature. It has bristly brownish fur over most of its body, with whitish underparts and grey feet. The scaly tail is dark in color, with very sparse fur. Adults range from 25 to 36 centimetres (9.8 to 14.2 in)
in total length, including the 10 to 15 centimetres (3.9 to 5.9 in) long tail, and weigh anything from 83 to 300 grams (2.9 to 10.6 oz). Males are slightly larger than females, but the two sexes are otherwise similar in appearance. [2]
Females have ten or twelve teats, suggesting a maximum litter size of around this number. Reproduction is thought to occur year-round. [2]
The Arizona cotton rat is found in southern and central Arizona, the extreme southwestern corner of New Mexico, [3] and in western Mexico from Sonora to Nayarit. [1] They live close to rivers, streams, and other sources of fresh water in semidesert, open grassland, or swampy habitats throughout the region. They rely particularly on areas of dense grassy vegetation. [4] Two of the five recognized subspecies are believed to have gone extinct during the twentieth century, [2] including the nominate subspecies, Sigmodon arizonae arizonae. Three subspecies therefore remain:
Oryzomys nelsoni is an extinct rodent of María Madre Island, Nayarit, Mexico. Within the genus Oryzomys of the family Cricetidae, it may have been most closely related to the mainland species O. albiventer. Since its first description in 1898, most authors have regarded it as a distinct species, but it has also been classified as a mere subspecies of the marsh rice rat (O. palustris).
A cotton rat is any member of the rodent genus Sigmodon. Their name derives from their damaging effects on cotton as well as other plantation crops, such as sugarcane, corn, peanut and rice. Cotton rats have small ears and dark coats, and are found in North and South America. Members of this genus are distributed in the Southwestern United States, Mexico, Central America, and South American countries of: Venezuela, Ecuador, Colombia, Peru, Brazil, Guyana, and Suriname. Many of the species are found in Mexico.
The woolly giant rat is a species of large burrowing rodent native to South America. No subspecies are currently recognised. It is the only member of the genus Kunsia.
The hispid cotton rat is a rodent species long thought to occur in parts of South America, Central America, and southern North America. However, recent taxonomic revisions, based on mitochondrial DNA sequence data, have split this widely distributed species into three separate species. The distribution of S. hispidus ranges from Arizona in the west to Virginia to the east and from the Platte River in Nebraska in the north to, likely, the Rio Grande in the south, where it meets the northern edge of the distribution of S. toltecus. Adult size is total length 202–340 mm (8.0–13.4 in); tail 87–122 mm (3.4–4.8 in), frequently broken or stubbed; hind foot 29–35 mm (1.1–1.4 in); ear 16–20 mm (0.63–0.79 in); mass 50–250 g (1.8–8.8 oz). They have been used as laboratory animals.
The white-throated woodrat is a species of rodent in the family Cricetidae. It is found from central Mexico north to Utah and Colorado in the United States. It is primarily a western species in the United States, extending from central Texas west to southeastern California. Populations east of the Rio Grande in New Mexico and Trans-Pecos Texas, previously considered to be variants of the white-throated woodrat, have since 1988 been assigned to the white-toothed woodrat.
The Galápagos rice rat, also known as the Galápagos oryzomys, is a species of rodent that is endemic to the Galápagos Islands.
The Tres Marías island mouse or Tres Marías deer mouse is a species of rodent in the family Cricetidae. It is found only on the Islas Marías off the west coast of Mexico. When last assessed, it was common on María Cleofás Island, but rare or absent on the other, more disturbed, islands.
The Nayarit mouse or Sinaloan deer mouse is a species of cricetid rodent endemic to Mexico. It was considered a subspecies of brush mouse until 1977.
Allen's cotton rat is a species of rodent in the family Cricetidae. It is endemic to western Mexico, where its distribution extends from Sinaloa to Oaxaca. The formerly recognized S. planifrons and S. vulcani are now considered conspecific with S. alleni by the IUCN.
The tawny-bellied cotton rat is a species of rodent in the family Cricetidae. It is found in Mexico and in the US states of Arizona and New Mexico.
The white-eared cotton rat is a species of rodent in the family Cricetidae. It is found only in Mexico.
The Jaliscan cotton rat or Mexican cotton rat is a species of rodent in the family Cricetidae. It is found only in Mexico. They commonly have brown fur with white fur on the belly. They are ground-dwelling and prefer open habitats.
The yellow-nosed cotton rat is a species of rodent in the family Cricetidae. It is native to Mexico and to the states of Arizona, New Mexico, and Texas in the United States, where it inhabits mountain grassland, scrub, and pinyon-juniper woodland. It is common over much of its wide range and the IUCN considers it to be of "least concern".
The southern pocket gopher is a species of rodent in the family Geomyidae. It is found in Mexico and the United States, usually in high altitude grassland and shrubland. It feeds on plant material and has an extensive burrow above which is a large heap of earth on the surface of the ground.
The Toltec cotton rat is a rodent species in the family Cricetidae. It is found in eastern Mexico from the Rio Grande to the Yucatán Peninsula, as well as in Belize and northern Guatemala. It prefers moist grassland habitat. While long thought to be a subspecies of S. hispidus, recent taxonomic revisions, based on mitochondrial DNA sequence data, have split the extensive former species range into three separate species. Carroll et al. (2004) indicate that the southern edge of the S. hispidus distribution is likely near the Rio Grande where it meets the northern distribution of S. toltecus. The range of S. toltecus extends from northern Mexico south into Chiapas where it occurs in sympatry with S. hirsutus . Rats from this species group have been used as laboratory animals.
The southern cotton rat is a rodent species in the family Cricetidae. It is found from southern Chiapas in Mexico through Central America, except for Belize, and as far east as northern Colombia and Venezuela. It lives in tropical rainforest, dry forest and savanna, as well as in cultivated areas. The species is terrestrial and primarily diurnal. It was long thought to be a subspecies of S. hispidus. However, recent taxonomic revisions, based on mitochondrial DNA sequence data, have split the extensive former species range into three separate species. Carroll et al. (2004) indicate that the southern edge of the S. hispidus distribution is likely near the Rio Grande where it meets the northern distribution of S. toltecus. The range of S. toltecus extends from northern Mexico south into Chiapas where it occurs in sympatry with S. hirsutus . Rats from this species group have been used as laboratory animals.
Oryzomys peninsulae, also known as the Lower California rice rat, is a species of rodent from western Mexico. Restricted to the southern tip of the Baja California peninsula, it is a member of the genus Oryzomys of family Cricetidae. Only about twenty individuals, collected around 1900, are known, and subsequent destruction of its riverine habitat may have driven the species to extinction.
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