Sciurus nayaritensis J. A. Allen 1890
Creators: name: Wilson, Don E.
name: Thomas E. Lacher, Jr
name: Mittermeier, Russell A.
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Mammalia
Rodentia
Sciuridae
Sciurus
Sciurus nayaritensis

description: 86. Mexican Fox Squirrel <i>Sciurus nayaritensis</i> <b>French:</b> Ecureuil du Nayarit / <b>German:</b> Mexiko-Fuchshérnchen / <b>Spanish:</b> Ardilla zorro de México <b>Other common names:</b> Apache Squirrel, Chiricahua Fox Squirrel, Nayarit Squirrel <b>Taxonomy.</b> Sciurus nayaritensis J. A. Allen, 1890, “Sierra Valparaiso, Zacatecas,” Mexico. Three subspecies are recognized. <b>Subspecies and Distribution.</b> S.n.nayaritensisJ.A.Allen,1890—SSierraMadreOccidental,fromSDurangotoNColima,WCMexico. S.n.apache].A.Allen,1893—SierraMadreOccidentalfromESonoraandWChihuahuatoDurango,NWMexico. S. n. chiricahuae Goldman, 1933 — Chiricahua Mts in SE Arizona (USA). <b>Descriptive notes.</b> Head—body mean 248-2 mm (males) and 259-1 mm (females), tail mean 245-8 mm (males) and 254-5 mm (females); weight mean 761 g (males) and 669 g (females). The Mexican Fox Squirrel has grizzled brown dorsum, with yellow, orange, or rufous venter and charcoal tail frosted with buff to white. Winter pelage is more rufous, and scrotum is often ringed with white. Nominate nayaritensis is diminutive, with more yellow in pelage. Subspecies apache is intermediate and color. Subspecies chiricahuae is large, and reddish throughout its pelage. <b>Habitat.</b> Dry forests from low-elevation (above 1500 m) Madrean pine (Pinus, Pinaceae)oak (Quercus, Fagaceae) forests to higher-elevation (c.2700 m) mixed conifer forests. Riparian areas with large cottonwoods (Populus, Salicaceae) and sycamores (Platanus, Platanaceae) often harbor highest densities of Mexican Fox Squirrels. <b>Food and Feeding.</b> The Mexican Fox Squirrel forages heavily on the ground but also regularly uses the canopy. It feeds on tree seeds, flowers, and fungi. Seeds are removed and consumed from cones of pines (Pinus), Douglas fir (Pseudotsuga menziesii), and true firs (Abies), all Pinaeae. Acorns (Quercus) and walnuts (Juglans, Juglandaceae) are readily eaten when available. Hypogeous and epigeous fungi are also a common food. Insects are consumed in opportunistic fashion. The Mexican Fox Squirrel occasionally scatterhoards large storable seeds in the soil. <b>Breeding.</b> The Mexican Fox Squirrel most often produces single litters of 1-2 young in late spring or summer,after a one day estrus in spring or early summer, during which as many as seven males pursue females. Males possess scrotal testes in winter through summer. Cavities in large-diameter, soft-wooded trees are favored by nursing females. <b>Activity patterns.</b> Mexican Fox Squirrels are diurnal and active throughout the year, with an early morning and late afternoon peak in activity in summer and unimodal pattern of activity in winter. <b>Movements, Home range and Social organization.</b> The Mexican Fox Squirrel constructs round dreys from pine needles, leaves, and twigs. Individuals generally live and forage alone, only occasionally interacting with others at concentrated food sources; however, communal nests are known to occur during winter. Foraging occurs in all canopy levels, with significant time spent on the ground. Males travel greater distances than females that result in home ranges of males that average 35 ha, much larger than those of females that average 15 ha. Males maximize home range overlap with females, especially during breeding. The Mexican Fox Squirrel is silent compared with most tree squirrels and seeks cover and remains motionless unless startled when it barks or chucks from elevated locations in the canopy. <b>Status and Conservation.</b> Classified as Least Concern on The IUCN Red List. Population trend of the Mexican Fox Squirrel is unknown. A lack of information on ecology, natural history, or threats likely impedes conservation and management efforts in Mexico; it might be vulnerable to deforestation and changing fire regimes. Local people hunt this large-bodied squirrel for meat and sport. It appearsto thrive in open forests maintained by frequent fire. <b>Bibliography.</b> Best (1995a), Brown (1984), Doumas &amp; Koprowski (2013a, 2013b), Hoffmeister (1986), Kneeland et al. (1995), Koprowski &amp; Corse (2001, 2005), Pasch &amp; Koprowski (2006a, 2006b), Thorington et al. (2012), Yensen &amp; Valdés-Alarcon (1999).
description: Published as part of <i>Don E. Wilson, Thomas E. Lacher, Jr &amp; Russell A. Mittermeier, 2016, Sciuridae, pp. 648-837 in Handbook of the Mammals of the World – Volume 6 Lagomorphs and Rodents I, Barcelona :Lynx Edicions</i> on page 747, DOI: 10.5281/zenodo.6840226