Glaucomys volans 97and larder-hoarded in trees or in the nest. Tree cavities are
preferred for nesting, and two or more nests are usually
maintained simultaneously, although one normally serves
as the primary nest. G. volans often competes for nest struc-
tures and can exclude some species (e.g., Red-Cockaded
Woodpeckers [Picoides borealis]) from nest hollows. One
avian cavity nester, the Great Crested Flycatcher (Myiarchus
crinitus), lines its nests with a piece of snakeskin, which ap-
pears to deter predation by G. volans. Nest aggregations as
high as dozens of animals occur primarily in northern re-
gions, for thermoregulatory conservation. Such nest aggre-
gations often consist of close relatives, which may reduce
the costs of intraspecifi c competition between nestmates.
G. volans also competes with tree squirrels for nest struc-
tures and, where the two Glaucomys species are sympatric,
it may exclude G. sabrinus from tree cavities. This species
shows a resting metabolic rate (RMR) that is 33–38 percent
lower than predicted by its body mass. However, less than
20 percent of this reduction is compensated for by the ther-
moregulatory advantages gained from communal nesting.
Instead, G. volans relies on nonshivering thermogenesis
(NST), which is negatively correlated with ambient temper-
atures and peaks in the winter. The higher energetic costs,
coupled with a reduced food supply, probably infl uence the
northern limit of this species’ range.
Courtship and mating are described in detail in the lit-
erature. Although two breeding seasons are reported, the
same females probably do not regularly breed during both
seasons. Parturition occurs in the spring (April–May) and
late summer (August–September); gestation is 40 days; the
young are hairless and weigh 3–5 g at birth. Litter sizes vary
between two and seven, but usually average about four. The
young may stay with the mother beyond the normal 8
weeks if conditions warrant it. Details of their development
are reported in the literature. G. volans may live as long as 10
yea rs i n capt iv it y. Popu lat ion densit ies va r y f rom 2 to 12 a n i-
mals/ha. Two studies listed mean home range sizes of 2.45
and 7.8 ha for adult males, and 1.95 and 3.8 ha for adult fe-
males. One study noted a mean home range size of 0.61 ani-
mals/ha for juveniles. At least two studies reported on the
homing ability of G. volans, citing homing distances of 1.0–
1.6 km. This species will frequently move through tree can-
opies by means of gliding. Glides of up to 90 m are possible;
details of their gliding mechanics and performance are
available in the literature.
This species is exclusively nocturnal and, as such, is pri-
marily vulnerable to predation by owls and snakes. G. vo-
lans hosts a number of ectoparasites and, because of its
highly carnivorous diet, a number of internal parasites as
well. At least six species of fl eas, three lice, four mites, three
protozoans, one acanthocephalan, one cestode, and fi ve
nematodes have been reported. The southern fl ying squir-
rel is also a reservoir host for ectoparasites that carry Rick-
ettsia prowazekii, which causes epidemic typhus. G. volans
has been used to study potential interactions between
Strongyloides robustus and Capillaria americana. It has been
hypothesized that the generally nonoverlapping geographic
ranges of G. volans and G. sabrinus may result from parasite-
mediated competitive exclusion, wherein the nematode
Strongyloides robustus, a common parasite of G. volans, is po-
tentially lethal to G. sabrinus. For example, recent parasite
surveys from the northeastern portion of the two species’
ranges show that where G. sabrinus and G. volans are sym-
patric, they both host S. robustus; but 100 km farther north,
where only G. sabrinus is found, the parasite appears to be
absent.Glaucomys volans. Photo courtesy Brian E. Kushner, BrianKush
nerPhoto.com.