94. Guianan Squirrel Sciurus aestuans French: Ecureuil de Guyane / German: Guayana-Hérnchen / Spanish: Ardilla de Guayana Other common names: Brazilian Squirrel Taxonomy. Sciurus aestuans Linnaeus, 1766, “Surinam.” Eleven subspecies recognized. Subspecies and Distribution. S.a.aestuansLinnaeus,1766—Nofthe AmazonRiverinColombia,Venezuela, theGuianas,andNBrazil. S.a.alphonseiThomas,1903—NEBrazil. S.a.garbeiPinto,1931—EBrazil. S.a.georgihernandeziBarriga-Bonilla,1966 —Colombia,NWBrazil,andVenezuela. S. a. henselı Miranda-Ribeiro, 194] - S Brazil, and NE Argentina. S. a. mgmmı Thomas, 1901 - E 8c S Brazil. S. a. mammnellı Thomas. 1901 - S Venezuela, Guyana, and N Brazil. S. a. poaıae Moojen. 1942 - Malo Grosso. Brazil. S. a. quelchıı Thomas, 1901 - S Guyana, and NC Brazil. S. a. sebastian: P. Müller 8:. Vesmanis, 1901 - São Sebastião l (Brazil). S. a. venustusJ. A. Allen, 1915 — Venezuela. Descriptive notes. Head—body 160-186 mm, tail 163-250 mm; weight 160-380 g. The Guianan Squirrel has an olivaceous gray dorsum, grizzled with brown and yellow. Pale yellow-brown eye ring is apparent, and similarly colored postauricular patch can be found on some individuals. Venter is yellowish, buff, or white. Dorsal surface of tail is same color as dorsum, with rufous and more variable underside. Albinism and melanism occur but are not common. Venter of subspecies differs primarily in color. Nominate aestuans has white postauricular patches and reddish wash to body and feet. Subspecies alphonsei has pale yellowish dorsum, with grayish venter. Subspecies ingrami has olivaceous dorsum, with white to buff venter. Subspecies garbei has ocherous chestnut upper parts and ocherous orange under parts, with paler throat. Sides of hensel: are ashy, and venter is white. Subspecies macconnelli is more brownish olivaceous. Subspecies poaiae is honey brown dashed with black and quelchii is olivaceous, with yellow belly. Subspecies sebastiani has stronger darker brown tone than mainland subspecies; tail is reddish brown, whereastails of mainland subspecies are gray-brown. Subspecies venustus is diminutive. Chromosomal complement is 2n = 40 and FN = 74. Habitat. Tropical rainforests, swamps and wet forests, Atlantic gallery forests, secondary forests, gardens, and plantations. Forest fragments and urban parks often include Guianan Squirrels as one of their few natural residents. Food and Feeding. Guianan Squirrels are generally herbivorous but have a varied and diverse diet. Seeds and fruits of the highly diverse palms (Arecaceae), oaks (Quercus, Fagaceae), and numerous other species are eaten. Fungi are eaten to supplement the diet in winter and spring. The Guianan Squirrel serves as an important seed disperser by carrying and caching fruit in autumn and winter, sometimesstoring it at heights of more than 30 m. Within forest fragments of the Atlantic Forest in south-eastern Brazil, the Guianan Squirrel accounts for 96% of the seed predation of some tree species. Breeding. Male Guianan Squirrels follow and sniff genitalia of females before estrus. On the day ofestrus, several males pursue a female to mate. Females are pregnant in winter and summer, suggesting two annual mating seasons. Litters of 2-5 young are born in leaf nests or tree cavities. Activity patterns. Guianan Squirrels are diurnal and active throughoutthe year. Movements, Home range and Social organization. The Guianan Squirrel constructs spherical dreys of leaves, palms, and twigs. Individuals live and forage alone. They are found in all forest levels and on the ground. Most commonly they are seen in the midstory at 5-12 m. Home range overlap is considerable; individuals overlap with a number of their neighbors. Average male home range (6-5 ha) is twice as large as that of females(3-1 ha) during the autumn mating season. The Guianan Squirrel has a diverse repertoire of vocalizations that includes alarm calls of sharp chucks and chatters, short chips, and highpitched whines. When alarmed, Guianan squirrels ascend a tree and chatter while fleeing. Status and Conservation. Classified as Least Concern on The IUCN Red List. Population trend of the Guianan Squirrel is unknown but suspected to be stable. Although it is one of the most studied squirrels of South America, lack of data on ecology, natural history, or threats likely impedes conservation and management efforts. The Guianan Squirrel is able to thrive in secondary forests and urban areas. Indigenous people occasionally hunt this small-bodied squirrel for meat. Bibliography. Alvarenga & Talamoni (2006), Bordignon & Monteiro-Filho (1999, 2000a, 2000b), Cullen et al. (2001), Fagundeset al. (2003), Galetti (1990), Galetti et al. (1992), Grelle (2003), Mendes et al. (2016), Mller & Vesmanis (1971), Paschoal & Galetti (1995), Souza (2000), Thorington et al. (2012).

Published as part of Don E. Wilson, Thomas E. Lacher, Jr & 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 on page 753, DOI: 10.5281/zenodo.6840226