Influence of environmental complexity and space on social interactions of mice (Mus musculus and Peromyscus leucopus).

Examined the effects of environmental space and complexity on social behavior in albino laboratory and wild house mice (M. musculus) and wild white-footed mice (Peromyscus leucopus). Pairs of males or females of each type were introduced into circular arenas of 0.5-, 1-, or 2-m diameter containing 0, 8, or 16 internal barriers. Behavioral characteristics were assessed by multivariate cluster and principal components analyses. Differences between laboratory Ss and the 2 wild groups of Ss reflected the better sensory capabilities and greater reactivity of the wild Ss. M. musculus and P. leucopus were reactive at greater distances, they spent more time freezing and/or grooming, and their behavior was influenced by environmental complexity. The laboratory Ss exhibited reactions only at short distances. M. musculus were more aggressive than P. leucopus, and M. Musculus males were more aggressive than females. Although the amount of space available influenced all 3 types of Ss, effects differed. Laboratory Ss simply encountered each other less often in larger areas, whereas both groups of wild Ss actively used the space to avoid other individuals. Male M. musculus were more aggressive as space decreased; female M. musculus and P. leucopus showed no such change. Behaviors related to orienting toward other mice and moving away from them were more frequent in more open areas. Vision appeared to be the sensory modality used, although audition may have played a role. (36 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)