Squirrels of the World

Poliocitellus franklinii 297

central USA. Its range extends from central Alberta to south-
ern Ontario (Canada), south through North Dakota and
Minnesota to Kansas, Missouri, Illinois, and Indiana (USA).
In much of the USA, the distribution of P. franklinii is highly
fragmented, and populations are rapidly disappearing be-
cause of loss of habitat.

geographic variation: None.

conservation: IUCN status—least concern. Population
trend—declining.

habitat: The preferred habitats of Franklin’s ground squir-
rel are thicker grasslands or grassland-prairie ecotones. Tall
dense vegetation is the primary variable that seems to best
characterize suitable habitat of this species.

natural history: This om nivorous g round squi rrel shows
seasonal shifts in its diet: from primarily vegetation in the
spring (which includes roots, shoots, and grasses) to seeds
and fruits later in the summer, when the animal is preparing
for hibernation. P. franklinii is reported to consume a great
variety of animal material, including bird eggs, adult birds,
frogs, mice, rabbits, and a variety of insects. This species
may be a particularly important predator of ground-nesting
birds. Its daily energy requirements are estimated at 3.08
calories g-1 h-1. P. franklinii is i ntolera nt of conspeci fi cs; males
are often solitary outside the breeding season. It is consid-
ered the most asocial of all the ground squirrel species.
These squirrels scent-mark with their oral, dorsal, and ante-
rioposterior glands; juveniles are capable of kin recognition,
but whether this infl uences nepotism is not yet known. P.
franklinii is diurnal, with the majority of its activity concen-
trated in the middle of the day. Two studies noted densities
ranging between 1.25 and 2.5 animals/ha. Home ranges over
the course of a year average 24.6 ha for males and 8.7 ha for
females. Franklin’s ground squirrels build complex branched
burrows with two to three openings. Diff erent branches of
the burrow are used for specifi c activities (i.e., nesting, storing
food, defecation). Adults enter hibernation any time between
early July and late August, but young animals remain above
ground and continue feeding until late August– October.
Males emerge one to two weeks before females and estab-
lish dominance hierarchies, as opposed to the territories of
other species of ground squirrels. Males and females some-
times reside together in the burrow, but males will always
disperse after mating. Gestation is 28 days. Litter sizes,
based on embryo counts from two studies and actual births
from a third, averaged 9.4, 7.5, and 7.9, respectively. Juvenile
Franklin’s ground squirrels disperse at 9–11 weeks of age. In
dispersing, both males and females can travel more than

1 km (up to 3.6 km for one male) across open fi elds, but they

typically avoid crossing major roadways; males usually dis-

perse farther than females.

Badgers (Taxidea taxus) are reported to be their primary

predator, although at least fi ve other species of carnivorous

mammals, and several species of raptors and snakes, are

also reported to prey on Franklin’s ground squirrels. This

species is host to a rather rich community of ectoparasites,

at least one of which shows high prevalence and intensity

levels. These ectoparasites include 2 ticks, 1 mite, and 11

species of fl eas, 9 of which are not reported for other

ground squirrels. Not surprisingly, given the animal mate-

rial in its diet, P. franklinii is also host to more helminths

than are typically observed in other species of ground squir-

rels. These parasites include 2 cestodes, 4 trematodes, and

5 nematode species. Three species of coccidians (Eimeria)

also reside in the digestive tract of this squirrel. The pulmo-

nary disease adiaspiromycosis, caused by the fungus Em-

monsia crescens (= Chrysosporium parvum var. crescens), is re-

ported in Franklin’s ground squirrels. P. franklinii, along with

several other rodent species, may serve as a reservoir host

for Bartonella infections. The earliest fossils for P. franklinii

are reported from the Middle to Late Pleistocene (Irvingto-

nian period).

Although this species is relatively common in most of the

northern parts of its range in Canada, its southern and east-

ern populations are rapidly declining and experiencing local

extinctions, due to habitat loss and fragmentation. Continued

fragmentation may prevent successful dispersal between

populations and, in turn, lead to a loss of genetic variability.

Poliocitellus franklinii. Photo taken by Paul Huber.