Population biology and spatial relationships of coexisting spiny mice (Acomys) in Israel

Nocturnally active Acomys cahirinus and diurnally active A. russatus cooccu r in hot rocky deserts, and their temporal partitioning results from compet ition. We studied their population biology at fin Gedi near the Dead Sea to determine their spatial relationships and gain insight into their ecologic al overlap. Individuals of both species were trapped repeatedly for almost 2 years. Mean body mass did not change seasonally, and A. russatus was sign ificantly heavier than A. cahirinus. Density of A. russatus was significant ly greater than that of A. cahirinus. Acomys russatus had a shorter reprodu ctive peak that overlapped the longer reproductive season of A. cahirinus. Acomys russatus showed a significant preference for boulder habitat versus open habitat at all seasons, whereas A. cahirinus showed a preference for b oulder habitat only half of the time. Sexes of both species overlapped in h ome range.