All five species of prairie dogs live in family groups that inhabit the same territory (Hoogland, 2002). While the family groups are called coteries for Black- tailed and Mexican prairie dogs, in White- tailed, Gunnison’s and Utah prairie dogs these groups are called clans (Hoogland, 2002). These two group classifications are similar, however coteries are much more close- knit social groups than clans (Haynie, Van Den Bussche, Hoogland, & Gilbert, 2002). Because of the large amount of sociality in coteries and the prevalence of the Black- tailed prairie dog, it is the social unit of the coterie that is most frequently studied. Usually the amicability between coterie members is much greater than the amicability between non coterie members (Hoogland, 1995). Amicable interactions between coterie members includes oral contact or "kissing" and grooming one another or "allogrooming" (Chance, 1976; Hoogland, 1995). These types of amicable interactions do not occur between prarie dogs of different coteries (Hoogland, 1995).

Photograph courtesy of Michael Bates

Although most people refer to communities of prairie dogs as prairie dog towns or colonies; coteries, not towns are the basic unit (Hoogland, 1995). A ward may refer to a subgroup within that town that is split by a physical barrier. Within these wards, however, are coteries. The number of coteries within one town ranges from 15 to 26 (Hoogland, 1995). An average coterie consists of one breeding male, two to three adult females and one or two male yearlings and one to two female yearlings. Because coteries usually consist of one breeding male and multiple females, prairie dogs are polygynous. Coteries are formed because of the strong philopatric attachment of females, while breeding resident male prairie dogs of the territory are the progeny of females from another coterie territory who relocated from their natal territory. Thus, when male prairie dogs reach maturity, they leave their natal territory and find a group of females to defend. The stability of the coterie relies on the females who stay in their natal territory all their lives (Hoogland, 1995).

Some deviations from the normal one male coteries exist. These deviations are multi- male coteries and half- male coteries (Hoogland, 1995). Multi- male coteries evolve when there are too many breeding females in one place for one male to gain control over. These larger female groups then have more than one male controlling and defending them. Two different types of multi- male coteries exist. These are coteries in which the males have unfriendly interactions and coteries in which the males have friendly interactions for the most part. The coteries in which unfriendly interactions occur make up the majority of the coteries that exist and are often made up of unrelated males. The females within these coteries usually mate with both males. The other type in which friendly interactions occur are made up of related males (Hoogland, 1995).

Half male coteries are coteries in which one male controls two to three groups of females around him (Hoogland, 1995). The sharing of the male between these coteries, however, does not increase the amicability between the two female groups (Hoogland, 1995).

Dominance Hierarchy

The size of male prairie dogs helps establish dominance (Hoogland, 2002). Larger prairie dog males are more likely than smaller males to gain and hold breeding territories. Thus intersexual selection determines which prairie dogs gain a territory. In addition, larger prairie dog males are more likely than smaller males to be chosen by females who are in estrus (Hoogland, 2002). This seems logical because the more the body mass of a male, the more food resources he will likely have in his territory (Hoogland, 1995). Larger males commonly sire more offspring, while larger females are also more reproductively successful and copulate sooner (Hoogland, 1995; Hoogland, 2002). Body mass may also serve to help males protect their territory and offspring from invading males that may commit infanticide. Although there exists dominance hierarchies within both sexes, the dominance hierarchy within males is visible throughout the year, while the dominance hierarchy within females is mostly only visible during the breeding season (Hoogland, 1995). There also seems to exist little difference in dominance between non reproductive yearling males (Hoogland, 1995).

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This page was created by Holly Smith, hosmith@davidson.edu in partial fulfillment of the requirements for Biology 323, Animal Behavior, at Davidson College in the Spring Semester 2004.