The Madagascan rousette (Rousettus madagascariensis) or Madagascar rousette, is a species of megabat in the family Pteropodidae endemic to Madagascar. Its natural habitat is subtropical or tropical dry forests. It is threatened by habitat loss.
The Madagascan rousette is a small fruit bat, the smallest of the three fruit bats endemic to Madagascar. The upper part of their bodies have a greyish fur while the underparts have a paler grey tinge. Like many other fruit bats, the Madagascan rousette have very dog-like faces with long, pointed snouts, large, wide eyes and largely separated ears. Like some other members of the genus Rousettus, these bats reside within cave roosts, suggesting the use of echolocation. These bats are a part of a larger group of fruit bats within Rousettus which consists of 10 different species. The Madagascan rousette primarily resides on western Indian Ocean islands.
The habitat of the Madagascan rousette is generally found to be associated with forests. They will roost well beyond the time of twilight. Many roosts have been found within caves however some bats have been found without a known cave roost, suggesting that the Madagascan rousette may sometimes roost within tree holes or other alternatives. They are observed to be highly mobile within a forest environment. This suggests that these bats could serve a role as pollinators and disperse seeds. The details of their diets are unknown but they have been observed to feed on introduced fruit as well as the fruits and nectar of endemic trees. They have also been found to primarily forage within eucalyptus forests.
Members of the family Pteropodidae have been known to be natural hosts for many different types of viruses emerging within and near the Indian Ocean. Madagascan rousettes have been assayed and found to have antibodies against viruses similar to Hendra, Nipah, and Tioman, suggesting that these viruses have circulated around Madagascar some time in the past. The Nipa virus is known to be harmful to humans, causing fevers and other symptoms potentially associated with death. These viruses are associated with the Paramyxoviridae family. These findings represent a potential health concern as Madagascan rousettes are commonly hunted and consumed by humans. However, further studies are needed to determine the extent of these risks.
Though deforestation does occur in the habitat of these rousette, it is not well understood how this affects the species. A number of roosting colonies have been observed some distance from forests. More research is needed to clarify the extent to which deforestation affects them. However, efforts to preserve these rousette have been made by local laws protecting them and their roosts within nature reserves.