92 Eupetaurus cinereusLocal people in Pakistan have noted a decline in this species
over the past few decades, probably resulting from the grow-
ing human population, a lack of forest regeneration due to
overgrazing by sheep and goats, and illegal deforestation.
general references: Yu, Yu, McGuire, et al. 2004; Zahler
1996, 2001; Zahler and Khan 2003.Glaucomys Thomas, 1908
This genus contains two species of fl ying squirrels.
Glaucomys sabrinus (Shaw, 1801)
Northern Flying Squirrel
description: G. sabrinus, usually weighing more than 100 g,
is larger than G. volans, the only other fl ying squirrel in
North America. Its fur is thick, and the hairs on the ventral
surface are lead colored, which help distinguish it from the
white or creamy white venter of G. volans. The tail is dark
gray; the skull length is greater than 36 mm, whereas that
of G. volans is always less than 36 mm. Where hybridization
of the two species occurs in the northeast, hybrids are inter-
mediate in size and pelage characteristics.
size: Female—HB 168.9 mm; T 129.4 mm; Mass 141.3 g.
Male—HB 158.8 mm; T 135.4 mm; Mass 141.9 g.
Sex not stated—HB 159.0 mm; T 133.5 mm; Mass 120.8 g.
distribution: This species ra nges t hroug h much of A laska
(USA) and Canada. It extends southward into the USA along
the Pacifi c coast and the Rocky Mountains, with isolated
populations in southern California. In the USA, G. sabrinus
is also found from the Black Hills of western South Dakota
east to the northeastern states and southward to the south-
ern Appalachian Mountains, although its range becomes
highly fragmented between New York state and Georgia.geographic variation: Tw e n t y-fi ve subspecies are rec-
ognized.G. s. sabrinus—interior of Canada, “from Fort Simpson
(possibly Fort Anderson), Mackenzie [River], and lower
Church i l l R iver, wes t side of Hudson Bay, sout h to nor t h-
ern Minnesota, extreme northwestern Wisconsin,
southern Ontario (vicinity of Lake Nipissing), and south-
ern Québec (Lake Edward)” (Howell). This squirrel is
also known as the Hudson Bay fl ying squirrel. The up-
perparts are vinaceous cinnamon; the sides of the head
are smoke gray; the eye ring and the dorsal surface of the
tail are fuscous; the ventral surface of the tail is shaded
with brown; and the underparts are soiled white, washed
with pale yellowish and shaded with drab.
G. s. alpinus—interior of British Columbia, extending slightly
over the northern border into the Yukon and over the
eastern border into southwestern Alberta (Canada).
Known as the Richardson fl ying squirrel, this form is
grayer and less vinaceous above. The tail is darker, wood
brown mixed with fuscous on both the dorsal and ven-
tral surfaces.
G. s. bangsi—USA, in the “mountains of central Idaho, east-
ern Oregon, southwestern Montana,” and northwestern
Wyoming (Howell). Known as the Bangs fl ying squirrel,
this form has more drab upperparts, grayer feet, and
pinkish cinnamon underparts.
G. s. californicus—USA, in the “San Bernardino and San Ja-
cinto Mountains, California” (Howell). Known as the
San Bernardino fl ying squirrel, this form is paler and
grayer than G. s. lascivus, and there is a grayish wash on
the front of the face. The upperparts are light drab to
yellowish wood brown, and the underparts are soiled
white washed with buff y.