Karroo rats are gregarious animals which live in colonies. They dig burrows and sometimes build nests of sticks and grass above the burrows. They are nervous, wary animals and stay near their shelter most of the time. Leaves of the saltbush tree provide the bulk of their diet, and they generally feed during the day. Every 3 or 4 years, their population decreases dramatically and they feed on agricultural crops, causing considerable damage. Karroo rats are believed to breed about four times a year, producing litters of 2 to 4 young.