Report

Prairie Dogs Disperse When All Close Kin Have Disappeared

Science  08 Mar 2013:
Vol. 339, Issue 6124, pp. 1205-1207
DOI: 10.1126/science.1231689

You are currently viewing the abstract.

View Full Text
As a service to the community, AAAS/Science has made this article free with registration.

Still Living in Their Mother's House

Dispersal, movement away from an organism's natal site, is a critical stage in the development of a juvenile into an adult and several drivers of this process have been proposed. A classic hypothesis put forward by Hamilton and May argues that individuals disperse away from kin in order to avoid competing with similar phenotypes. Many species have been shown to follow this pattern, and it is generally accepted that most organisms disperse well away from the sites where they were born. However, not all species follow this pattern and some display a distinct tendency to remain within their mother's home range. Hoogland (p. 1205) studied populations of three species of prairie dogs over more than three decades and found that the presence of close kin in these highly social rodents actually led young animals to remain on their natal site, whereas dispersal away from it occurred almost exclusively when close female kin were absent. This suggests that sociality may in fact result in individuals remaining with their close kin in order to benefit from cooperation and that longer-distance dispersal may instead occur when the opportunity for cooperation does not exist.

Abstract

Because competition decreases inclusive fitness among kin, Hamilton and May predicted that the presence of nearby kin should induce the dispersal of individuals from the natal territory, independent of pressures to avoid inbreeding. Many studies support this landmark prediction, but research over 31 years with prairie dogs reveals the opposite pattern: Young females are 12.5 times more likely to disperse in the absence of mother and siblings for one species, and 5.5 times more likely for another species. Such striking patterns probably occur because cooperation among kin is more important than competition among kin for young prairie dogs. The inability to cooperate with close kin, due to their absence, prompts a search for a new territory where cooperation might be less crucial for survival and reproduction.

View Full Text