Effects of Captivity on Response to a Novel Environment in the Oldfield Mouse (Peromyscus polionotus subgriseus)

Long-term maintenance of captive populations and release of these animals into the wild is one ap-proach to endangered species conservation. In this study, I used a traditional ethological technique, the open-field test, to assess captivity's effects on exploratory behavior, level of activity, and enclo-sure use in oldfield mice (Peromyscus polionotus subgriseus) upon introduction to a novel environ-ment. The animals tested were from four populations collected from Ocala National Forest, Florida, and were held in captivity for varying numbers of generations: 35, 14, 2, and 0 (wild caught). The population 35 generations removed from the wild was behaviorally distinct from the other three populations. The mechanisms behind the differences are unclear. This study, however, is an example of how traditional behavioral methods can be applied to conservation problems. Whether captive populations are raised for lab studies or for captive breeding of endangered species, this study sug-gests that if they have been removed from the wild for more than 14 generations, they are likely to be significantly different from the wild counterparts of interest. In the wild, animals need to locate resources such as food, water, and shel-ter while avoiding predators and other sources of mortality. Behaviors associated with resource acquisition and predator avoidance have been shaped over evolu-tionary time to increase reproductive success. Captivity and the selective pressures associated with it, however, are vastly different from the environment and pres-sures in which species have evolved (Frankham et al., 1986; Hediger,1964