The breeding season and diet of the rat Arvicanthis was monitored from December 1983 to November 1985 in the semi-arid Sudan savanna at Kano, Nigeria, West Africa. Breeding began 1–2 months before the start of the rainy season and ceased at the beginning of the dry season. The diet of Arvicanthis was omnivorous, but with seasonal differences. Monocotyledons and dicotyledons predominated in the diet in the dry season, with seeds and insects increasing in the diet in the rainy season. The major differences between the ecology of Arvicanthis at Kano and on the East African savanna were that in East Africa the breeding season is longer and begins after the start of the rainy season. These and other dissimilarities between the biology of Arvicanthis in the two areas could be due to the effect of climatic differences on food supply and to the possible existence of different taxonomic groupings of Arvicanthis in the two regions.

The movement and spatial distribution of marked Nile rats, Arvicanthis niloticus, was traced through phases of a low density population from January to August 1981, a rapidly growing population from September to January 1982, and a high and declining post-reproductive population from February to April 1982. Apart from late in the population cycle there was considerable movement, interchange and establishment of new ranges. As the population increased individual ranges became smaller. The rats apparently preferred field edges and did not favour the fields themselves. Females frequently established themselves at certain sites where they produced their litters; some of the offspring remained with the mother in the warren. There is also evidence that ousiders of both sexes joined these warrens. Males were generally more wide-ranging than females. Agricultural practices, e.g. mowing and trampling by cattle, influenced the rats preparedness to remain within a particular location. Exploitation of all the available habitat took several months to achieve.