Rodrigues Flying Fox

Whereas most bats are nocturnal, the Rodrigues flying fox is different. They are crepuscular and so are most active at sunset and sunrise when they leave their caves or trees to find food (4). This species hunts for night flying insects, using their wings as nets to draw the prey into the mouth. Bats belonging to the sub-order microchiroptera use echolocation to navigate in the darkness and hunt for insects, but the Rodrigues Flying fox belongs to the sub-order megachiroptera, and like other species in this group, they do not echolocate (8). Their ears are much smaller than those of echolocating bats, and instead they have evolved large eyes to see and hunt in the dark (6). As well as preying on insects, this species feeds on fruit, as its other common name indicates. By eating fruit these bats help scatter the seeds of fruit trees and pollinate many trees and shrubs (4). By living in large groups this species benefits from there being many more eyes to scan for danger, allowing more time for individuals to feed and mate. A female will give birth once a year to single offspring and occasionally have twins (6). The young will not be ready to reproduce until they are 1.5-2 years old, which compared to most other mammals of their size is a particularly slow reproductive rate. This is a crucial problem for their conservation because their reproductive rate is not high enough to withstand the increasing threats they face (5).

In 1976 the Rodrigues fruit bats were on the brink of extinction. This species' survival in the wild seemed unlikely, prompting the Jersey Preservation Trust to collect 25 bats for a captive breeding project (5). This species is now part of an international Species Program (SSP) with 16 participating North American Institutes (5) and in 1992 was listed as 'Priority Grade 1' in the IUCN's Action Plan for Old World Fruit Bats, putting it into the most urgent conservation category (8). Over the years, habitat protection, conservation measures, breeding projects and community education programmes have allowed the Rodrigues Flying fox to make a slow but steady recovery. The population on the island has most recently been estimated at 3000 and rising (4), while Jersey zoo currently has some 70 bats. Their breeding projects are so successful they have to now keep males and females separately to limit the zoo's numbers. Jersey zoo also sent bats to 33 other institutions worldwide, which altogether now hold over 765 bats in captivity (4). Despite these encouraging signs they remain listed as Critically Endangered on the IUCN Red List since their numbers are still fragile and dependant on conservation measures (1). There are future plans to upgrade and expand the bats' accommodation areas in Jersey Zoo, make changes based on the genetic health of the bats to avoid inbreeding, and implement more conservation practices based on new knowledge of the bats, in order to help this species on the road to recovery (4) (8).

The Rodrigues flying fox gained its name because of its fox like large pointed ears, elongated snout and large eyes. Despite these features, this species is a bat, and is grouped under the order of mammals known as the chiroptera, which in Greek means 'hand-wing' (4). Of the mammals in chiroptera about one sixth, including this species, belong to the sub-order megachiroptera which, as mega implies, defines the larger bat species (4). The Rodrigues flying fox body is fairly small but its wing span can be up to 90 cm, with lightweight bones in the wings, facilitating flight (5). Two thin layers of skin are stretched between these finger-like bones, to make the bat's wing (6). This skin can amazingly stretch as much as three or four times the length of the bat's body giving it its huge wing span and is so thin that the wings are almost see through (7). Most flying fox species are brown but the Rodrigues flying fox is brightly coloured, and may be yellow, orange and red or silver and black. Males and females are similar in appearance, with the offspring also looking like the adults (6).

This species is found living in mangroves and rain forests where they roost in trees or in caves and rock shelters. Flocks will normally favour a particular roosting site which they occupy for years, however, human disturbance and increased hunting pressure can cause colonies to relocate to new roosting sites in sub-optimal habitat (5).

In the wild, the Rodrigues flying fox is only found on the island of Rogrigues in the southwestern Indian Ocean (1).

Classified as Critically Endangered (CR B1 + 3d) on the IUCN Red List 2002 (1), and listed on Appendix II of CITES (3).

This species is in grave danger of extinction in the wild on Rodrigues Island as a result of habitat loss, shooting and hunting for meat (5). These are believed to be the causes of its extinction in Mauritius where the species was once found in the wild. Now it is only observed there in captivity. These bats also face severe natural threats annually of tropical cyclones which blow animals out to sea where they die as well as destroy their habitats, depriving them of food and shelter (4).