Sunday, March 10, 2013

Prairie Dogs Disperse When All Close Kin Have Disappeared

Unlike most species, that tend to leave a territory in order to avoid competition from relatives, prairie dogs will leave their home territory after all of their relatives have disappeared.  Three species of prairie dogs contain individuals that are more likely to disperse in the absence of nearby relatives.  Behavioral ecologist John Hoogland recently published an article in Science regarding this new study.  He has been studying the ecology and social behavior of prairie dogs in the national parks of Arizona, South Dakota, and Utah for the past 40 years.  According to his study, females are 12.5 times more likely to disperse when close kin are absent for one species, and 5.5 time more likely for another species.
Hoogland stated, "Prairie dogs are excellent models for a study of dispersal because they are easy to live-trap, mark, and observe.  And they usually move only short distances to nearby territories."
He also stated that prairie dogs do compete with nearby kin for resources, such as burrows and mates.  However, they also cooperate with each other in the digging burrows, defense of the home territory,giving alarm calls when large predators are nearby or have attacked, and helping to chase away small predators.  Prairie dogs also participate in communal nursing (the suckling of non-offspring), which can be life-saving for the offspring of close kin when the biological mother has died.
Hoogland hypothesizes that the benefits of cooperation with close kin exceed the costs of competition with them.  He believes that when all close kin disappear, individuals disperse because they have nobody with whom to cooperate.  When possible, prairie dogs often disperse to a territory that contains close kin who dispersed there beforehand, allowing cooperation amongst kin.

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