Rodents are of concern as reservoirs and transmitters of pathogens that cause zoonotic and other diseases in domestic animals and humans. The contact between wild and urban rodent fauna is increasing in expanding cities in Africa, and this arguably increases the risk of disease transmission to urban populations. When rodents from rural areas are accidentally introduced into cities and encounter urban rodents, for example, in markets, grain mills and butcheries, there is a potential that pathogens are transferred between rural and urban rodent populations. Using a non-toxic biomarker, Rhodamine B (RB), we investigated the distances over which rodents are active around such potential introduction sites. Animals feeding at such sites were traced up to 100 m distant within a period of 10 days. We found that RB is a practical alternative for studying rodent movements. These results may be useful in designing management strategies to reduce the risk of the introduction of new rodent-borne pathogens in cities.