Sciurus niger Linnaeus 1758
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 niger

description: 80. Eastern Fox Squirrel <i>Sciurus niger</i> <b>French:</b> Ecureuil fauve / <b>German:</b> Fuchshérnchen / <b>Spanish:</b> Ardilla zorro oriental <b>Other common names:</b> Bryant's Fox Squirrel, Cat Squirrel, Delmarva Fox Squirrel, Fox Squirrel, Stump-eared Squirrel, Western Fox Squirrel; Big Cypress Fox Squirrel (avicennia) <b>Taxonomy.</b> Sciurus niger Linnaeus, 1758, “in America septentrionalis.” Restricted by O. Thomas in 1911 to southern South Carolina, USA. Ten subspecies are recognized. <b>Subspecies and Distribution.</b> S.n.nigerLinnaeus,1758—NorthCarolina,SouthCarolina,Georgia,SEAlabama,andthepanhandleofFlorida(SEUSA). S.n.avicenniaA.H.Howell,1919extremeSFlorida(USA). S.n.bachmaniLowery&amp;Davis,1942—MississippiandAlabamainSEUSA. S.n.cinereusLinnaeus,1758—DelmarvaPeninsulainDelaware,Maryland,andVirginia(EUSA). S.n.imitisBaird,1855—CTexas(USA)andNCoahuilaandNNuevoLeon(Mexico). S.n.ludovicianusCustis,1806—ETexasandWLouisiana(USA). S.n.rufiventerE.GeoffroySaint-Hilaire,1803—SCCanada,inSSaskatchewanandSManitoba,andCUSA,WofAppalachianMtsandNfromOklahoma,Arkansas,andTennessee. S.n.shermaniMoore,1956—N&amp;CFlorida(USA). S.n.subauratusBachman,1839—WbankofMississippiRiverinELouisianaandSEArkansas(USA). S. n. vulpinus Gmelin, 1788 — Pennsylvania, West Virginia, Maryland, and N Virginia (USA). Introduced (probably rufiventer) into Arizona, California, Colorado, Idaho, Montana, New Mexico, Oregon, and Washington in the USA and Ontario in Canada. <b>Descriptive notes.</b> Head—body 260-370 mm,tail 200-330 mm; weight 0.5-1.4 kg. The Eastern Fox Squirrel has highly variable pelage on dorsum, venter, and tail. Individuals from the western and northern parts of the distribution are grizzled with suffusion of buff to orange and white-to-cinnamon, but usually rufous, venter. In the southeast,, dorsal pelage is grizzled buff-gray to agouti-black, with white, tan, or rust venter. Most striking are highlights of white or cream on snout, ears, and feet, often with black nape and crown. The Eastern Fox Squirrels in the north-eastern coastal part ofits distribution are silvery gray, washed with buff or pale red on haunches, feet, and head, with white to pale gray, occasionally cinnamon venter, and tail of pale gray. Tails are impressive in size and typically are colored like dorsum, suffused with ventral color and frosting of white-cream to buff-orange. Melanism occurs occasionally and can be common, especially in the southern part of the distribution. Nominate niger is highly variable, with buff, gray, and black forms, often possessing white snouts, ears, and feet and white-to-cream venter. Subspecies avicennia is highly variable, with dark brown, tawny, and cinnamon forms, with white snouts, ears, and feet and buff, orange, or black venters. Subspecies bachmani has grizzled brown dorsum, with orangish venter and a black head with varying amounts of white-buff on ears and snout. Subspecies cinereus is a silver-gray, grizzled finely with black; venter is white to cream. Subspecies limatis is a modest-sized, with grizzled dorsum and cinnamon venter. Subspecies ludovicianus is large-bodied, with light reddish tone to dorsum and venter. Subspecies rufiventeris the most common and widespread, with orange to rust-colored venter. Dorsum of sherman: is nearly all black to silvery gray, grizzled with black; head is often black, with white ears and muzzle, venteris tawny, and tail is the same color as dorsum and frosted with white. Subspecies subauratus is diminutive, with rich dark reddish dorsum and venter. Subspecies vulpinus is grayish, suffused with orange reddish on dorsum and white to cream on venter. Chromosomal complementis 2n = 40 and FN = 76. <b>Habitat.</b> Variety of forested environments but thrives in open woodlands, with open ground and shrub level vegetation with scattered trees. Where grasslands dominate the western distribution, the Eastern Fox Squirrel inhabits sparsely forested riparian areas and fencerows. Open hardwood forests and savannas are frequented in the northern and central parts of the distribution. In the southeast, individuals are found in open pine (Pinus, Pinaceae) woodlands, diverse deciduous forest swamps and scattered swamp-bound stands of bald cypress (Taxodium, Cupressaceae) and pine. The Eastern Fox Squirrel often occurs in urban and residential areas and agricultural matrices. <b>Food and Feeding.</b> The Eastern Fox Squirrel is herbivorous but will opportunistically feed on a variety of foods. Tree seeds and nuts are the most important in diets, but fruits, buds, flowers, herbs, bark, and sap are also consumed. Hypogeous and epigeous fungi also can be important foods. Animal matter is also eaten including insects, larvae, bird eggs, nestlings, fish, and even conspecifics. Most conspicuous is the annual autumnal habit of scatterhoarding of hard nuts and acorns of low perishability for recovery during winter food scarcity. Squirrels collect tree seeds at the parent tree, disperse to distant locations, and bury seeds beneath the surface. Food caches are recovered in winter and spring using spatial memory and olfactory cues. <b>Breeding.</b> Although mating can occur in November—July, local populations typically have two annual seasons in November—February and April-July. Males follow females’ reproductive condition by approaching and sniffing their genitalia. Males congregate at the nest of the female at sunrise, or in some low-density populations, they may have slept in the female’s nest the night prior to estrus. On her single day of estrus each breeding season, as many as eleven males will pursue a female during her mating bout and emit a snort or wheeze as a call during the chase. Dominant males pursue and mate with the female; low-ranking males copulate by waiting on the periphery of the mating chase in the event that the female evades aggression of dominant males. Copulation lasts less than 30 seconds after which a copulatory plug forms within the female from the coagulation of semen. Females will remove the plugs and mate with several males. After gestation of 44-45 days;litters averaging 2-7 young are born in nests. Some females produce two litters in a year. Young emerge from the nest after 6-8 weeks and are weaned by c.12 weeks. Adult size is not reached until after one year of age. Although a rare female may breed at c.8 months of age, most individuals do not reproduce until at least their yearling year. All males and females disperse from their natal areas soon after weaning. <b>Activity patterns.</b> Eastern Fox Squirrels are diurnal and active throughout the year. Activity is distinctly bimodal in summer with early morning and late afternoon-early evening peaks in activity and midday lull. Winter activity is unimodal and focused during relative warmth of midday. During periods of extreme inclement weather, Eastern Fox Squirrels can enter short periods of torpor within a nest. <b>Movements, Home range and Social organization.</b> Eastern Fox Squirrels den in cavities within trees or construct spherical dreys of leaves, pine needles, and twigs. Although generally asocial, groups of unrelated males and occasionally females nest together at night. Cheek glands are used to scent-mark trees, and these glands are smelled when individuals meet. Traditional scent marking sites are found in protected areas, such as under low branches or on undersides of slanted tree trunks. Males gnaw bark at the location and wipe their cheeks back and forth to deposit scent, sometimes urinating. Home ranges overlap considerably, but females with young may defend exclusive-use core areas, and adult females are important in regulating settlement. Home ranges are 0-9-42-8 ha, larger for males, and decrease with habitat fragment size. Alarm calls are series of medium-pitched barks, often followed by long high-pitched whines dependent on level of disturbance. <b>Status and Conservation.</b> Classified as Least Concern on The IUCN Red List. Population trend of the Eastern Fox Squirrel is stable. Subspecies cinereus was listed as endangered in the USA, and a nonessential experimental population was established in Sussex County, Delaware, USA, to aid in recovery. Recovery effort was successful, and cinereus was removed from the US endangered specieslist in 2015, with an estimated population of more than 20,000 individuals. Subspecies avicennia, cinereus, shermani, and vulpinus are of special concern in parts of their distributions and afforded state protection. The Eastern Fox Squirrel is a game species throughout its distribution and is highly prized as food. It is also valued in parks and cities as wildlife that is easily watched, and it provides an educational opportunity for studies of ecology and behavior. Furthermore, by burying seeds, the Eastern Fox Squirrel plays an integral role in the succession of grasslands to mature forests. It can be a pest in gardens, fields of agricultural crops (corn/maize, oats, wheat, soybeans, and sorghum), and orchards (apples, oranges, blueberries, and cherries), especially where it was introduced in California. Habitat loss and fragmentation remain the most significant conservation threats to Eastern Fox Squirrels. <b>Bibliography.</b> Adam (1984), Bertolino (2009), Ceballos (2014), Derge &amp; Steele (1999), Geluso (2004), Kellam et al. (2016), Koprowski (1991, 1993b, 1993d, 1994b, 1996), Kotler et al. (1999), McCleery et al. (2008), Schmidt (2000), Steele &amp; Koprowski (2001), Steele &amp; Weigl (1992), Thomas (1911c¢), Thorington et al. (2012), Thorson et al. (1998), Wrigley et al. (1991).
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 pages 743-744, DOI: 10.5281/zenodo.6840226