The species R. lanosus often is placed in the subgenus Stenonycteris Andersen, 1912. Males are substantially larger than females. The upper parts are usually brownish, the underparts somewhat lighter. At least two species, R. amplexicaudatus and R. leschenaulti, have a pale collar of short hairs. Otherwise, Rousettus tends to have a drab appearance.
Rousette bats occur in a variety of habitats, from lowlands to mountains.
They roost in ancient tombs and temples, rock crevices, garden trees, and date plantations but are most common in caves. The diet consists of fruit juices and flower nectar. In the course of obtaining nectar from different flowers, these bats carry pollen from one place to another. They have been noted at dusk flying around flowering acacia trees. The bats crowded closely together in caves, maintaining bodily contact.