I examined dispersal and social organization of Gunnison's prairie dogs (Cynomys gunnisoni) for 7 years at Petrified Forest National Park, Arizona. Within colonies, individuals lived in harem-polygynous family groups called clans. The number of clans at the study site each year ranged from 21 to 23, with a mean of 22.3. Clan size (the number of adults living in the same territory) ranged from 1 to 19, with a mean of 5.30. Clans contained 1.06 ± 0.39 (SD) breeding males, 3.01 ± 2.08 breeding females, and 1.23 ± 1.65 non-breeding yearling males. Some clans contained two breeding males, and others contained no resident breeding male. The area of clan territories ranged from 0.16 ha to 1.82 ha, with a mean of 0.67 ha. Females were more likely than males to copulate as yearlings (100% versus 24%). Ninety-five percent of females (340/358) remained in the natal clan territory for life, but only 5% of males (3/66) remained in the natal clan territory for >1 year after weaning. Dispersal of both sexes was most commonly to an adjacent clan territory. Infanticide at the study colony was rare or absent.

Author notes

Associate Editor was Edward J. Heske.