The spatial patterns presented by the marsupial Micoureus demerarae were studied through capture–mark–recapture in two small Atlantic Forest fragments (areas 7.1 and 8.8 ha). The study took place from March 1995 to August 1997. Considering all captures of each individual, males did not have larger home ranges within the fragments than did females. A negative correlation was found between home range sizes and population densities. For males, home ranges overlapped often, and were larger during the breeding season. For females, home ranges did not overlap except for a short period when there were many individuals present, and home range sizes were not significantly larger in the breeding season. Five movements between the two forest fragments were detected, across 300 m of open vegetation. All the movements were performed by males during the reproductive season. M. demerarae in the small fragments therefore displays a metapopulation structure, although possibly an atypical one where only males disperse.