Madagascan rousette  (Rousettus madagascariensis)

The Madagascan rousette is classified as Near Threatened (NT) on the IUCN Red List (1).

The Madagascan rousette (Rousettus madagascariensis) is the smallest of Madagascar’s three endemic fruit bats (3). Its body is greyish-brown on the upperparts, with reddish-brown tinges, and paler grey-brown on the underparts. The fur is quite long and dense, but shorter on the neck, throat and shoulders. The wings are relatively broad (2).

As in other fruit bats, the face of the Madagascan rousette is rather dog-like, with a pointed muzzle, large eyes, and fairly conspicuous, widely separated ears (2) (4). Although most fruit bats rely on sight and smell as their main senses, some members of the genus Rousettus also use a rudimentary form of echolocation, producing high-pitched clicks with the tongue to help detect obstacles in their path. The association of the Madagascan rousette with cave roost sites suggests that this species is also likely to possess this ability (2) (4) (5).

The Madagascan rousette is endemic to Madagascar, where it generally widespread, but rare or absent from the central highlands and the arid southwest (6).

Typically inhabiting lowland rainforest and deciduous forest (2) (5) (7), the Madagascan rousette has also been recorded in Eucalyptus plantations, in agricultural areas and in villages (1) (8).

Although it may roost in large trees and in tree holes, this bat prefers roosting sites in caves, and so may be largely restricted to areas where suitable caves are present (1) (2) (7).

The Madagascan rousette feeds mainly on the juices of fruits, soft fruit pulp and nectar. It may play an important role in the forest as a pollinator and seed disperser (1) (2) (5) (9), particularly as its small size makes it the only fruit bat in Madagascar that can fly within intact forest (1) (3).

The rudimentary echolocation of this species is likely to be used only for orientation, with food being detected using vision and scent. The Madagascan rousette flies considerable distances each night in search of food (2) (9). It is also probably capable of longer-distance flights, and appears to be a rather mobile species that is readily able to disperse across the island (10). Emerging from caves at dusk puts the Madagascan rousette at risk of predation by owls and raptors (11).

This species may form roosts of up to several hundred individuals (2), although a single cave roost of over 5,000 has also been recorded (12). During the daytime, roosts are noisy and the bats are often restless, continually competing for the best positions. Fights are not uncommon (2) (5). In general, Rousettus species have extended breeding seasons which follow the rains, sometimes with two peaks each year (5). A study in the east of Madagascar found that the Madagascan rousette gives birth to a single young (9).

The Madagascan rousette is believed to have undergone a decline of around 20 to 25 percent in recent decades. Although often the most commonly trapped species during scientific surveys, it is seriously threatened by overhunting (1) (3) (7) (13). Most hunting occurs at the roosts, by local people, with the bats caught in locally made traps or knocked down from the cave ceiling using sticks (1) (13).

The Madagascan rousette may also potentially be killed as a pest of fruit crops (1). Under Malagasy law, the Madagascan rousette is a game species, and as such only receives protection where it occurs in nature reserves, or where it roosts at sacred sites (1) (14). However, many reserves receive little real protection, and the national hunting season for bats is also largely ignored (7) (13).

Since fruit bats produce only a single offspring each year, they are particularly susceptible to overhunting (13). Forest destruction and degradation are likely to compound these problems (1) (7), although the extent to which the Madagascan rousette is impacted by deforestation is not yet fully understood (1).

The Madagascan rousette occurs in several protected areas within Madagascar, including Ankarana Special Reserve and Tsingy de Bemaraha National Park (1) (7) (15). However, roost sites are in need of more effective protection both within and outside of these areas, and cooperation with local communities is likely to be vital (1) (13).

Other recommended conservation actions for the Madagascan rousette include further studies into its biology and ecology, especially its reproductive behaviour (7). A number of organisations have already been active in investigating the diet and foraging behaviour of the Madagascan rousette, as well as investigating the patterns and impacts of hunting. Various environmental education programmes have also been initiated, to increase awareness of bat conservation amongst local communities (3) (14). However, unless the Madagascan rousette can be effectively protected against overhunting and the effects of habitat loss, it may become increasingly threatened in the future.

View information on this species at the UNEP World Conservation Monitoring Centre.

Find out more about the conservation of fruit bats:

• Lubee Bat Conservancy:
  http://www.lubee.org/
• Madagasikara Voakajy:
  http://www.madagasikara-voakajy.org/