Evolution, genetics and ecology of burrowing behavior in deer mice (genus Peromyscus)

Behavioral differences among closely related species can result from adaptation via natural selection, and this is especially true of innately expressed behavior that shows evidence of complex design or function. A major goal of biologists is to understand how and why complex, adaptive behavior evolves. To this end, I investigated the evolution, ecology and genetics of innate burrowing differences in deer mice (genus Peromyscus). First, I show that several species of deer mice recapitulate their natural burrowing habits under laboratory conditions, even after many generations of captive breeding. When I compare these behaviors in the context of phylogeny, I find that burrowing is species–specific. I also find that the complex burrows of the oldfield mouse (P. polionotus), which have both a long entrance and an escape tunnel, likely arose from simple behavior similar to that expressed by two closely related species.