Spermophilus dauricus 303are highly specialized, even for a ground squirrel. This spe-
cies is somewhat social and polygynous; males appear to
assist in the excavation of burrows later occupied by their
mates and their young. However, males that exhibit this pa-
rental investment are often individuals with lower mating
success. As has been observed in many ground squirrels,
earlier litters are larger than those produced later in the sea-
son. In S. citellus, this is apparently due to diff erences in ma-
ternal investment. Females show signs of two periods of
estrus: one soon after emergence, and another later in sum-
mer that does not result in reproduction, because males are
sexually inactive at that time. It is suggested that the hor-
monal changes associated with the second estrus may in-
crease fat storage for hibernation and thus allow females to
enter estrus soon after their spring emergence. Populations
of S. citellus undergo signifi cant cycling, and they sometimes
cra sh; densit ies va r y f rom a low of 5 to a s ma ny a s 60 a n i ma l s/
ha. During periods of low population density, male ag gres-
sion i s reduced, juven i les a re able to repro duce, home ra nges
increase in size, and litter sizes are larger. In contrast, at
high densities male aggression is increased, reproductive
success among males is more variable, the animals lose
mass, and emigration rates increase. Early reproduction ap-
pears to correspond with lower growth rates, higher levels
of aggression, and possibly reduced health. Other than
three species of Eimeria, few parasites are reported from this
host. Evidence of fragmentation, genetic isolation, and in-
breeding suggest that many populations are in peril, espe-
cially on the periphery of this species’ range.
general references: Aschauer et al. 2006; Çolak and Öz-
kurt 2002; Coroiu et al. 2008; Everts et al. 2004; Golemansky
and Koshev 2007; I. E. Hoff man et al. 2003; Huber, Hoff -
mann, et al. 2001; Huber, Millesi, and Dittami 2002; Huber,
Millesi, Walzl, et al. 1999; Hulová and Sedlácek 2008; Koshev
2008; Lagaria and Youlatos 2006; Millesi, Hoff mann, and
Huber 2004; Millesi, Hoff mann, Steurer et al. 2002; Millesi,
Huber, Dittami et al. 1998; Ruediger et al. 2007; Millesi, Hu-
ber, Everts, et al. 1999; Millesi, Huber, Pieta, et al. 2000; Mil-
lesi Strijkstra, et al. 1999; Özkurt et al. 2007; Strauss, Mascher,
et al. 2007; Váczi et al. 2006.
Spermophilus dauricus Brandt, 1843
Daurian Ground Squirrel
description: S. dauricus is a small ground squirrel with a
short tail. The pelage is buff y or grayish brown, with no
dorsal spots or lines. There is a black ring near the distal end
of the tail, and the tip is light yellow.
size: Female—HB 190.2 mm; T 55.3 mm.
Male—HB 191.4 mm; T 63.2 mm.
Sex not stated—HB 196.1 mm; T 59.1 mm; Mass 223.8 g.distribution: This species’ range extends from Transbai-
kal (Russia) into Mongolia and northeastern China.geographic variation: We consider this species to be
monotypic, but three subspecies are sometimes recognized:
S. d. dauricus, S. d. mongolicus, and S. d. ramosus.conservation: IUCN status—least concern. Population
trend—no information.habitat: S. dauricus is found in open plains, steppes, and
deserts. It occurs along the northern edge of the Gobi Des-
ert into northern Mongolia and Siberia, and along the east-
ern edge of the Gobi into China, where it is found in nine
provinces.natural history: The diet of the Daurian ground squirrel
consists mostly of plant material and seeds, including some
grains and other crops. The squirrels hibernate in simple
underground burrows that are usually just a few meters in
length, with nests that are less than 1 m belowground. One
litter is produced annually (in the spring), ranging in size
from two to nine young. Theoretical life-table analyses of
S. dauricus from northeastern China and the Columbian
ground squirrel (Urocitellus columbianus) show that the two
species have similar life-history traits; further, these analy-