Rodent Societies: An Ecological & Evolutionary Perspective

1984). In this chapter, I discuss interspecific differences
among three species of prairie dogs regarding the frequency
of infanticide and the sex of killers.

The Study Animals

Prairie dogs (Cynomys) are diurnal, colonial, herbivorous,
harem-polygynous, burrowing rodents of the squirrel fam-
ily (Sciuridae), and thus are akin to marmots (Marmota),
tree squirrels (Sciurusand Tamiasciurus), flying squirrels
(Glaucomys), chipmunks (Tamias), and ground squirrels
(Spermophilus and Ammospermophilus; Hafner 1984;
Harrison et al. 2003). On a typical day, prairie dogs emerge
from their burrows at dawn and forage aboveground un-
til dusk. Reasons to submerge temporarily during daylight
hours include nest-building, copulation, infanticide, nurs-
ing of offspring, and retreat from either predators or severe
weather.
Mammalogists currently recognize five species of prairie
dogs, which comprise three distinct groups (Hollister 1916;
Kelson 1949; Pizzimenti 1975; Hoogland 1995, chap. 40
this volume): black-tailed and Mexican (C. ludovicianus
andC. mexicanus), Gunnison’s (C. gunnisoni), and Utah
and white-tailed (C. parvidensand C. leucurus). In this
chapter I summarize information from one species of all
three groups.
Colonies of prairie dogs are subdivided into territorial
family groups that typically contain one breeding male and
several breeding females. For Gunnison’s and Utah prairie

dogs, these groups are called clans(Fitzgerald and Lechleit-

ner 1974; Wright-Smith 1978; Travis et al. 1995, 1996).

For black-tailed prairie dogs, family groups are called cote-

ries(King 1955).

Methods

Periods of research

I studied black-tailed prairie dogs at Wind Cave National

Park, South Dakota, from February through June of 1975 –

1988 (Hoogland 1995, 1996a); Gunnison’s prairie dogs

at Petrified Forest National Park, Arizona, from March

through June of 1989 –1995 (Hoogland 1998a, 1999); and

Utah prairie dogs at Bryce Canyon National Park, Utah,

from March through June of 1996 –2005 (Hoogland 2001,

2003b).

Aging, livetrapping, eartagging, marking

To capture adult prairie dogs, I use double-door livetraps

(15 cm 15 cm 60 cm), and for juveniles I use single-

door livetraps (13 cm 13 cm 40 cm; Tomahawk Live-

trap Company, Tomahawk, Wisconsin). For permanent

identification of individuals, I insert one fingerling eartag

in each ear (National Band and Tag Company, Newport,

Kentucky). To identify prairie dogs from a distance, I

apply unique markers to the pelage of each individual with

Nyanzol-D black dye (Greenville Colorants, Clifton, New

Alarm Calling, Multiple Mating, and Infanticide among Black-Tailed, Gunnison’s, and Utah Prairie Dogs 439

Table 37.1 Possible costs and benefits of alarm calling, multiple mating by females, and nonparental infanticide

Behavior Possible costs Possible benefits

Alarm calling Increased susceptibility to predation Warning kin; warning others likely to reciprocate with later
alarm calls; diversion of predator’s attention to other prey;
discouragement of pursuit by predator; reduced probability
of later attacks by same predator
Multiple mating by females Increased susceptibility to predation; increased probability Increased sustenance from courtship feeding or nutritious
of physical harm; increased exposure to diseases and para- spermatophores; higher probability of conception; reduced
sites; reduced paternal care, if males do not help to rear off- harassment from courting males; reduced probability of losing
spring of mate that also copulates with other males offspring to infanticide; fresh sperm for fertilization; promotion
of sperm competition; increased survivorship of offspring re-
sulting from higher genetic diversity within litters via multiple
paternity; increased paternal care, if male helps to rear off-
spring of all females with whom he copulated
Nonparental infanticide Retaliation by victimized parent(s); killing of nondescendant kin Removal of future competitors for both killer and killer’s off-
spring; sustenance via cannibalism of victim(s); lower probabil-
ity of misdirecting parental care; higher reproductive success
for male killers if infanticide induces victimized mother to be-
come sexually receptive more quickly

SOURCE: References for alarm calling: Sherman 1977, 1985; Blumstein, chapter 27, this volume. References for multiple mating: Schwagmeyer 1984; Westneat et al. 1990;
Eberhard 1996; Newcomer et al. 1999; Wolff and Macdonald 2004. References for infanticide: Hrdy 1979; Sherman 1981b; Hausfater and Hrdy 1984; Hoogland 1985;
Ebensberger and Blumstein, chap. 23, this volume.