African four-striped grass mice (Rhabdomys pumilio), a diurnal-crepuscular muroid rodent, in the behavioral laboratory

Abstract

African four-striped grass mice, Rhabdomys pumilio, are potentially valuable animals for laboratory studies of behavior. In nature, they live in the grasslands of much of Africa. In the laboratory, striped mice adapt well to a number of behavioral testing situations. Ten male grass mice tested in running wheels displayed a mean of approximately 10,000 revolutions per day, with a diurnal-crepuscular pattern characterized by sharp peaks near the time of light onset and offset and a generally greater level of wheel running in light than in darkness. The retinal anatomy of this species is characterized by a cone-like organization of the outer segment layer and unusual thickness of the inner plexiform layer, suggesting an unusual high amount of retinal data processing for a muroid rodent. The copulatory pattern of R. pumilio is characterized by no lock, no intravaginal thrusting, multiple intromissions preceding ejaculation, and multiple ejaculations. The number of intromissions preceding the first ejaculation is unusually high, and postejaculatory intervals are unusually long. Grass mice display intermediate levels of open-field activity, but little climbing or digging. © 1979 Psychonomic Society, Inc.