The Mexican fox squirrel (''Sciurus nayaritensis'') is a species of

tree squirrel Tree squirrels are the members of the squirrel family (Sciuridae) commonly just referred to as "squirrels." They include more than 100 arboreal species native to all continents except Antarctica and Oceania. They do not form a single natural, o ...

found throughout the

Sierra Madre Occidental The Sierra Madre Occidental is a major mountain range system of the North American Cordillera, that runs northwest–southeast through northwestern and western Mexico, and along the Gulf of California. The Sierra Madre is part of the American ...

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

as far south as Jalisco — and northward into the

Chiricahua Mountains The Chiricahua Mountains massif is a large mountain range in southeastern Arizona which is part of the Basin and Range province of the west and southwestern United States and northwest Mexico; the range is part of the Coronado National Forest. ...

of southeastern

Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...

, U.S.Best, T.L. (1995) ''Sciurus nayaritensis''. Mammalian Species 492, 1-5. This species, or its subspecies, is sometimes called the Nayarit, Apache, or Chiricahua fox squirrel. It has been evaluated as an

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biol ...

Least Concern A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...

species.

Description

Physical

The Mexican fox squirrel has a grizzled brown back with a yellow to rufous underside, and a charcoal tail frosted with white. Two molts occur each year; the winter pelage is more rufous and the scrotum is often ringed with white.Thorington, R.W., Jr., Koprowski, J.L., Steele, M.A., and Whatton, J. (2012
''Squirrels of the World''
Johns Hopkins University Press, Baltimore, 472 pp. Mass is approximately .

Behavior

Mexican fox squirrels are diurnal, non-territorial, and do not hibernate during the winter months. ;Food sources The Mexican fox squirrel forages extensively on the ground and in the forest canopy for tree seeds, flowers, and fungi. Seeds from the cones from pine, Douglas-fir, and true firs are extracted by removing individual cone scales. Acorns and walnuts are also eaten when available, along with a variety of other tree seeds,

hypogeous Hypogeal, hypogean, hypogeic and hypogeous (; ) are biological terms describing an organism's activity below the soil surface. In botany, a seed is described as showing hypogeal germination when the cotyledons of the germinating seed remain non ...

and occasionally epigeous fungi, and insects. Mexican fox squirrels occasionally cache large seeds by scatterhoarding them in leaf litter and topsoil. The ecology of the Mexican fox squirrel has not been studied thoroughly, particularly outside the United States. Densities are often very low.Pasch, B.S., Koprowski, J.L. (2005) Correlates of vulnerability in Chiricahua fox squirrels, in: Gottfried, G.J., Gebow, B.S., Eskew, L.G., Edminster, C.B. (Eds.), ''Proceedings: Connecting mountain islands and desert seas: biodiversity and management of the Madrean archipelago II''. USDA Forest Service, Gen. Tech. Rep. RMRS-P-36, Rocky Mountain Research Station, Fort Collins, CO, pp. 426-428. Large raptors, canids, felids,

procyonids Procyonidae is a New World family of the order Carnivora. It comprises the raccoons, ringtails, cacomistles, coatis, kinkajous, olingos, and olinguitos. Procyonids inhabit a wide range of environments and are generally omnivorous. Characte ...

and snakes are likely the major predators. Mexican fox squirrels typically produce a single small litter of 1 or 2 young in late spring or summer. Mexican fox squirrels nest in ball-shaped

drey A drey is the nest of a tree squirrel, flying squirrel or ringtail possum. Dreys are usually built of twigs, dry leaves, and grass, and typically assembled in the forks of a tall tree. They are sometimes referred to as "drey nests" to distin ...

s composed of sticks and leaves in trees; cavities within large trees are occasionally used, especially by nursing females. They are known to communally nest at times. Mexican fox squirrels are notably silent and appear to prefer to seek cover and remain motionless. If startled, they may bark and chuck from safe locations in trees.

Habitat

Mexican fox squirrels are found in forests ranging from low elevation (~) Madrean forests with a mixture of pine and oak to higher elevation mixed conifer forests < .Hoffmeister, D.F. (1986) ''Mammals of Arizona''. The University of Arizona Press, pp. 212-213. Riparian areas with large cottonwoods and sycamores often harbor the highest densities. In the United States, the squirrel lives only in the Chiricahua Mountains of southeastern Arizona. The Mexican fox squirrel inhabits forests that were historically maintained by frequent, low-severity fire, and uses areas with open understory and large trees that are typical of such forests.

Geographic variation

There are three subspecies. * ''Sciurus nayaritensis nayaritensis'' (Nayarit fox squirrel): southern portion of the distribution range. This is a smaller and more yellowish subspecies. * ''Sciurus nayaritensis apache'' (Apache fox squirrel): northern and central portion of the distribution range. This is a subspecies intermediate in size and coloration. * ''Sciurus nayaritensis chiricahuae'' (Chiricahua fox squirrel): an endemic subspecies of the Chiricahua Mountains of southeastern Arizona (US). Characterized as more reddish throughout.

References

External links

Smithsonian National Museum of Natural History—North American Mammals: ''Sciurus nayaritensis''
{{Taxonbar, from=Q1765556

Mexican fox squirrel The Mexican fox squirrel (''Sciurus nayaritensis'') is a species of tree squirrel found throughout the Sierra Madre Occidental of Mexico as far south as Jalisco — and northward into the Chiricahua Mountains of southeastern Arizona, U.S.Best, T ...

Rodents of North America Mammals of Mexico Mammals of the United States Fauna of the Southwestern United States

Chiricahua Mountains Fauna of the Sierra Madre Occidental Least concern biota of Mexico Least concern biota of the United States Mammals described in 1890 Taxonomy articles created by Polbot