Habitat loss, hunting and agricultural/urban disturbance are the most serious and common threats to P. rufus. An increasing human population is rapidly decreasing the available habitat, as the native forests are cleared for agriculture and trees are used for timber and firewood. Forest loss is mainly due to slash-and-burn agriculture, which results in thousands of hectares of forest loss per year. It is estimated that about 90% of Madagascar's original vegetation has been lost. In many deforested areas the degraded landscape is now dominated by savanna-type grassland and in central and western Madagascar these prairies are burnt annually for cattle grazing. This barren habitat cannot support fruit bats, which require tall trees for roosting and forested areas for feeding. Consequently, loss of suitable habitat is cited as the main cause of roost desertion and localized extinctions, after disturbance due to hunting, for P. rufus. The most popular methods of hunting are traditional and not thought to cause serious damage to populations, however, shotguns are used at most of the known roosts and cause quite considerable destruction.
These animals use all modes of communication at various times. Tactile communication occurs between mothers and their offspring as well as between mates. Males mark their territories with scents, and use scent cues in females to determine their estrus condition.
Unlike most bats, P. rufus does not rely on ecolocation as their primary means of communication or locomotion. Pteropus rufus mainly uses scent and sound to distigush other roost mates. They also can use sight or polarized light to move about the forest at night. According to a 1995 honors thesis by M. Wells from the University of Aberdeen, P. rufus has 6 distinct calls decribed as a squawk, male whinny, female whinny, chatter, squak, and a honk.
Communication Channels: visual ; tactile ; acoustic ; chemical
Other Communication Modes: scent marks
Perception Channels: visual ; polarized light ; tactile ; acoustic ; chemical
According to the IUCN red list, P. rufus previously was listed as Lower Risk, least concern in 1996. Improved information since then has resulted in the species being reassessed as Vulnerable. Habitat has declined by 20 to 50% over the last 20 years due to deforestation. In addition to habitat loss and degradation, the species is hunted for food, traditional medicine, and sport. The combination of these threats has resulted in a decline of by 30% in population size over the last three bat-generations (15 years). Continued hunting pressure is expected to result in a further decrease of at least 30% over the next 15 years
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: vulnerable
These animals are not known to impact humans negatively, except that they may occasionally raid fruit crops.
Negative Impacts: crop pest
The people of Madagascar benefit from the bats by using them for food; the bats have been hunted by humans for many generations. People also profit from large bats by selling them at local markets. These bats also benefit local people by dispersing seeds of many fruit trees.
Positive Impacts: food ; research and education; produces fertilizer; pollinates crops
Generally, fruit bats are the primary means of seed dispersal for many tropical plant species. Bats are particularly important in oceanic island ecosystems where they are often the only flying animals big enough to transport larger seeds. Pteropus rufus feeds on a wide variety of fruit, which makes this species an important seed disperser for a large number and diverse set of endemic plant species of the littoral forest. According to Bollen, P. rufus compared to other frugivores in the littoral is the only one capable of long distance seed dispersal, since foraging may occur up to 50 km away from the roost site. This allows these bats to bridge gaps between isolated forest fragments.
Ecosystem Impact: disperses seeds; pollinates
Mutualist Species:
Pteropus rufus consumes mainly liquids, consisting mostly of juice extracted from fruit pulp. Fruit is chewed and the pulp pressed against the ridged palate so that the juice can be extracted. Bats spit out the remaining dry matter, containing seeds and pulp, in the form of pellets. Examination of fecal material indicates that the bats also consume pollen and leaves, presumably to make up for the low protein levels available in fruit. When presented with insects such as meal worms or crickets, the bats will occasionally eat them.
The diet of P. rufus at the Berenty reserve is narrow, containing only 17 plant species. At Sainte Luce, the diet of P. rufus consists of 40 endemic species. Agave sisalana was present in 84% of bat fecal samples. A little under 66% of the feces was produced from fruit, about 25% from leaves, and the remainder from pollen.
The digestive tract is simple and food takes an average of only half an hour to pass through the gut. These bats have a rather high-energy requirements and may eat at least the equivalent of their own body mass each night. Fruit bats, including Pteropus rufus, are the primary means of seed dispersal and potentially an important pollinator for many tropical plant species. In 92% of germination trials, bat-passed seeds had the highest percentage germination and fastest rate of germination, compared with seeds from ripe fruits or those having passed through the guts of other frugivores.
The role of P. rufus in pollination is inferred from the presence of pollen on the head and thorax of bats, as well as that found in their feces.
Animal Foods: insects
Plant Foods: leaves; seeds, grains, and nuts; fruit; nectar; pollen
Primary Diet: herbivore (Frugivore )
Madagascar flying foxes, Pteropus rufus, are endemic to the Island of Madagascar, off the Southeast coast of Africa. At over 594,000 sq km, Madagascar is the fourth largest island in the world. It contains a great diversity of habitats and species. A narrow strip along the east coast contains most of the island's rainforest and is where the majority of Madagascar flying foxes can be found.
Biogeographic Regions: ethiopian (Native )
Other Geographic Terms: island endemic
Roost sites of P. rufus are frequently found along the coastal lowlands of Madagascar. The coast line includes a narrow strip of humid littoral forests, with low elevation from sea level up to 800 m. This littoral forest of eastern Madagascar has been shrinking rapidly since the island was first colonized by humans 2,000 years ago. The forest now exists as isolated fragments, all of which are under constant and increasing pressure from local inhabitants. These specialized humid forests have adapted to the sandy substrates within several kilometers of the shoreline. They have long been recognized as a particularly important center of endemism and biodiversity, with hundreds of species of vertebrate animals and perhaps thousands of species of plants that are strictly endemic to this region, including P. rufus.
Range elevation: sea level to 800 m.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: rainforest
Other Habitat Features: agricultural
Information on the longevity of this species is scant. According to the Lubee Bat Conservancy, Pteropus species can live for approximately 30 years in captivity. The Lubee Foundation has a unique collection of species housed in captivity which includes the largest (1.2 kg, Pteropus vampyrus) and the smallest (180 g, Pteropus pumilus) species of the genus Pteropus. Observation of other Pteropus species held in captivity indicate that individuals typically live between 9 and 17 years. Pteropus rufus is probably like other members of the genus in terms of lifespan.
Average lifespan
Status: wild: 30 years.
Typical lifespan
Status: captivity: 9 to 17 years.
Pteropus rufus is the largest bat in Madagascar. Nose and ears are long and pointed, the eyes are large, and there is no obvious tail. The skin is dark-brown at the lower surface, and yellowish brown on the top surface. The front of the head and throat are seal-brown, with the back of the head showing yellowish-brown coloration. Around the neck this species is yellowish- to reddish-brown. The wingspan is approximately 1 m.
Males and females look similar, but differ in size, with adult males ranging from 526 to 750 g and adult females ranging from 500 to 645 g. Lengths of 24.3 to 25.2 cm have been reported.
Range mass: 500 to 750 g.
Range length: 24.3 to 25.2 cm.
Range wingspan: 122 to 125 cm.
Sexual Dimorphism: male larger
Other Physical Features: endothermic ; bilateral symmetry
Pteropus rufus populations are diminishing at a steady pace due to over-hunting for both the bush-meat trade and subsistence food. These bats are caught when feeding in sisal plantations, and can be purchased in local markets.
Raptors, such as Madagascar harrier hawks, can potentially be a threat to the bats. When disturbed by raptors, these bats often fly away. Within the Berenty reserve, dead bats marked by talons have been found around hawk nests. After comparing the various raptor species within the reserve, it was determined that Madagascar harrier hawks had taken the bats. Goodman states that Harrier hawks exploit P. rufus roosts at the Berenty reserve for young bats that drop to the ground or become isolated from their mothers. They also occasionally feed upon adults.
Known Predators:
Mating appears to be either polygynous or polygynandrous. At the beginning of the mating season, males mark territories with scent. They do this by rubbing their chins and necks along branches and twigs. Male genitals become larger at this time.
Males smell females as soon as they enter the roost to check their estrus status. Mating takes place while hanging upside-down from tree branches. Males will approach females from behind, grab them by the scruff of the neck using their jaws, and attempt to pin the female's wings.
Mating System: polygynous ; polygynandrous (promiscuous)
Females typically give birth once per year, around October, to a single offspring. Occasionally, females can give birth to twins. The birth weight of each offspring is around 13 to 17% of the adult's body weight. The female's gestation period is about 100 to 150 days and delayed implantation of the fertilized ovum is possible. Nursing of the offspring last for the first 4 to 5 months. For its body size, this species has a slow reproductive rate, with young not reaching reproductive maturity until 1.5 to 2 years.
Breeding interval: This species breeds annually.
Breeding season: Breeding occurs from April to May.
Range number of offspring: 1 to 2.
Average number of offspring: 1.
Range gestation period: 100 to 150 days.
Range time to independence: 4 to 5 months.
Range age at sexual or reproductive maturity (female): 1.5 to 2.0 years.
Range age at sexual or reproductive maturity (male): 1.5 to 2.0 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous ; delayed implantation
After a 100 to 150 day gestation period, female P. rufus give birth to one or two offspring around October. Nursing occurs for the first 4 to 5 months. For the genus Pteropus, offspring can be considered independent when they weigh 50% or more of their parents’ weight. The young bats typically stay within their natal social groups.
Sources have not provided any information on the various forms of parental investment by P. rufus. Females necessarily provide their young with milk and protection, but the role of males is less well understood. Information on the parental investment of the family Pteropodidae is also limited.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); post-independence association with parents
