Neophobia and neophilia: New-object and new-place reactions of three Rattus species.

Abstract

The new-object and new-place reactions of 2 strains of laboratory rats, the commensal (wild) R. norvegicus, and the indigenous Australian rats R. fuscipes and R. villosissimus, were studied in an artificial environment, the +-maze. There were species and strain differences in the magnitude of initial response to the mazes, but the pattern of response was similar for each group. Visits to and time spent in the maze arms were highest in the 1st h and declined thereafter. The indigenous rats and the laboratory rats showed little hesitation to investigate new objects in a familiar area; by contrast, commensal rats avoided such objects, usually for at least 24 h. But when allowed access to an unfamiliar place, commensal rats, like the laboratory and indigenous rats, immediately investigated the new place. New-object and new-place reactions are discussed in relation to the development of the commensal habit.