As climbers, roof rats are more likely to cause structural damage in homes as they chew on wood and wires. Like Norway rats, roof rats eat a wide variety of foods, but they prefer fruits, nuts, berries, slugs, and snails. Roof rats are especially fond of avocados and citrus, and they often eat fruit that is still on the tree. If roof rats are living in the attic of a residence, they can cause considerable damage with their gnawing and nest-building activities. Roof rats prefer to nest in locations off the ground and rarely dig burrows for living quarters if off-the-ground sites exist.
If roof rats are seen exposed, it often indicates that their hiding spaces are all filled by other rats or that they have been disturbed, such as by construction. Droppings are another good indicator of roof rat activity. Roof rat droppings are 4-1/2 to 5 inches with pointed ends (whereas Norway rat droppings are 7 to 7-1/2 inches) and capsule shaped. Other indicators can include grease marks which are produced as the rodent travels along an edge, and the oils in their fur are deposited. Indoor nests usually are constructed in insulation such as in attics.