Stephen's woodrat (''Neotoma stephensi'') is a species of

rodent Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and Mandible, lower jaws. About 40% of all mammal specie ...

in the family

Cricetidae The Cricetidae are a family of rodents in the large and complex superfamily Muroidea. It includes true hamsters, voles, lemmings, muskrats, and New World rats and mice. At over 870 species, it is either the largest or second-largest family ...

found in

Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...

New Mexico New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...

and

Utah Utah is a landlocked state in the Mountain states, Mountain West subregion of the Western United States. It is one of the Four Corners states, sharing a border with Arizona, Colorado, and New Mexico. It also borders Wyoming to the northea ...

in the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

Description

Individuals of ''N. stephensi'' are small with long, silky fur and a slightly bushy tail. They are colored grayish buff with a paler head and a pinkish buff belly. They have white fur on their pectoral, inguinal (groin), foot, and occasionally throat regions. Their ears and topside of their tail have grayish-brown fur. They have a short and broad skull with a small and smoothly rounded braincase; broad, flat frontal region; large bullae; and a first upper molar without an antero-internal sulcus.

Similar species

''N. stephensi'' resembles the species '' Neotoma lepida'', but can be distinguished by its larger hind foot, color, and the shape of its skull, which is generally larger with a longer toothrow, larger interparietal bone, and smaller bullae than that of ''N. lepida''.

Habitat and distribution

''N. stephensi'' was first identified in the Hualapai Mountains of Arizona at an altitude of . ''N. stephensi'' inhabits rocky areas and mountains within pinyon-juniper woodlands, sometimes but not usually near cliffs. They may also live among yellow pines, cacti, or agave. Their middens are made of debris and constructed among rocks or around the bases of trees, as well as above ground in juniper. They occur in the ranges from central Arizona to southern Utah, western New Mexico to the north of

Grant County Grant County may refer to: Places ;Australia * County of Grant, Victoria ;United States * Grant County, Arkansas * Grant County, Indiana * Grant County, Kansas *Grant County, Kentucky Grant County is a county located in the northern pa ...

, and up to the Mohave County in west Arizona, but may be extinct in Utah.

Behavior

''N. stepheni'' is nocturnal. They do not hibernate, and they do not aestivate.

Life cycle

One generation of ''N. stepheni'' is two years long. They breed in winter and early fall, and juveniles appear from March to May. ''N. stepheni'' may have up to two or more litters per year, from 1–5 offspring per litter with an average of two. Females are sexually mature at 9–10 months and typically do not survive to reproduce next season.

Diet

''N. stepheni'' primarily consumes foliage and juniper seeds, and may learn to selectively eat junipers that have low levels of toxic defensive chemicals. They may also feed on ephedra, but they are primarily a

specialist species A generalist species is able to thrive in a wide variety of environmental conditions and can make use of a variety of different resources (for example, a heterotroph with a varied diet). A specialist species can thrive only in a narrow range of en ...

on '' Juniperus monosperma''. When compared to another woodrat species, the generalist species '' Neotoma albigula'', the activity of the protein Permeability-glycoprotein (Pgp) was found to be 2.4 times higher in the small intestine of ''N. stephensi'' than that of ''N. albigula''. Pgp is a transport protein that prevents toxins from entering

epithelial Epithelium or epithelial tissue is a thin, continuous, protective layer of cells with little extracellular matrix. An example is the epidermis, the outermost layer of the skin. Epithelial ( mesothelial) tissues line the outer surfaces of man ...

cells, thus suggesting that it allows ''N. stephensi'' to consume a diet with much higher amounts of juniper leaves and the toxins within them.

Conservation

''N. stepheni'' is not threatened. Furthermore, there are

protected areas Protected areas or conservation areas are locations which receive protection because of their recognized natural or cultural values. Protected areas are those areas in which human presence or the exploitation of natural resources (e.g. firewoo ...

in the natural range of ''N stepheni''.

References

{{Taxonbar, from=Q1765064 Neotoma Mammals described in 1905 Taxonomy articles created by Polbot