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Pteropus rufusMadagascan flying fox

By Ashley Parsons

Geographic Range

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. ("Ecology of Pteropus Rufus in Madagascar", 2004)

Habitat

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. (Bollen and Van Elsacker, 2002)

  • Range elevation
    sea level to 800 m
    to 2624.67 ft

Physical Description

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. (Goodman, 1989; Grzimek and Main, 1990; Williams, 2001)

  • Sexual Dimorphism
  • male larger
  • Range mass
    500 to 750 g
    17.62 to 26.43 oz
  • Range length
    24.3 to 25.2 cm
    9.57 to 9.92 in
  • Range wingspan
    122 to 125 cm
    48.03 to 49.21 in

Reproduction

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. (Grzimek and Main, 1990; Long, et al., 2001)

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. ("Ecology of Pteropus Rufus in Madagascar", 2004; Grzimek and Main, 1990; O'Connor, et al., 2005)

  • 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

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. ("Ecology of Pteropus Rufus in Madagascar", 2004; Grzimek and Main, 1990; Long, et al., 2001; O'Connor, et al., 2005)

  • 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

Lifespan/Longevity

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. ("Ecology of Pteropus Rufus in Madagascar", 2004)

  • Average lifespan
    Status: wild
    30 years
  • Typical lifespan
    Status: captivity
    9 to 17 years

Behavior

Pteropus rufus has an island-wide distribution, roosting mainly near the coasts in groups of several hundred to several thousand individuals. Most roost sites are year-round, but the bats are very sensitive to disturbance. With a large amount of disturbance, a group of bats can move mid-season to a new roosting site, but will occasionally return to the old roost and use both. One of the largest roosts is found at the Private Reserve of Berenty, where the colony varies in size from around 600 bats during the cyclone season (December through March) to over 1,800 bats at the height of the dry season (August through October).

During the mating season, dominant male bats have territories on the roost tree which they patrol to exclude other males. Female bats roost within the male territories. Outside the mating season, most territories are not maintained (even though the bats tend to roost in the same place year-round). There are feeding territories as well, established by dominants on desirable fruit trees. Males can travel up to 50 km from the roost site to get food.

As recently as 60 years ago, P. rufus was a widely abundant species, reportedly roosting in groups of several hundred to a million individuals. Unfortunately, with loss of habitat due to the rapid rate of deforestation and increasing pressure from hunting, this bat is no longer as numerous as it once was. The most recent total population estimate is 300,000 bats. ("Ecology of Pteropus Rufus in Madagascar", 2004; Bollen and Van Elsacker, 2002; Long, et al., 2001)

  • Range territory size
    17 to 22 km^2

Communication and Perception

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. ("Ecology of Pteropus Rufus in Madagascar", 2004; Grzimek and Main, 1990)

Food Habits

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. ("Ecology of Pteropus Rufus in Madagascar", 2004; Bollen and Van Elsacker, 2002; Long, et al., 2001; O'Connor, et al., 2005; Williams, 2001)

  • Animal Foods
  • insects
  • Plant Foods
  • leaves
  • seeds, grains, and nuts
  • fruit
  • nectar
  • pollen

Predation

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. ("Ecology of Pteropus Rufus in Madagascar", 2004; Goodman, 1989; Williams, 2001)

  • Known Predators
    • Humans
    • Madagascar harrier hawls

Ecosystem Roles

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. ("Ecology of Pteropus Rufus in Madagascar", 2004; Bollen and Van Elsacker, 2002; Williams, 2001)

  • Ecosystem Impact
  • disperses seeds
  • pollinates
Mutualist Species
  • angiosperm families such as, Moraceae, Myrtaceae, Sapotaceae, Arecaceae, Piperaceae, Solanaceae, Anacardiaceae, Guttiferae, Leguminosae, and Combretaceae

Economic Importance for Humans: Positive

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. (O'Connor, et al., 2005; Williams, 2001)

  • Positive Impacts
  • food
  • research and education
  • produces fertilizer
  • pollinates crops

Economic Importance for Humans: Negative

These animals are not known to impact humans negatively, except that they may occasionally raid fruit crops. (Hutcheon, 1997)

  • Negative Impacts
  • crop pest

Conservation Status

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 (O'Connor, et al., 2005)

Other Comments

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. ("Ecology of Pteropus Rufus in Madagascar", 2004; O'Connor, et al., 2005; Williams, 2001)

Contributors

Ashley Parsons (author), Humboldt State University, Brian Arbogast (editor, instructor), Humboldt State University.

Nancy Shefferly (editor), Animal Diversity Web.

Glossary

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

acoustic

uses sound to communicate

agricultural

living in landscapes dominated by human agriculture.

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

arboreal

Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

colonial

used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.

crepuscular

active at dawn and dusk

delayed implantation

in mammals, a condition in which a fertilized egg reaches the uterus but delays its implantation in the uterine lining, sometimes for several months.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

fertilization

union of egg and spermatozoan

food

A substance that provides both nutrients and energy to a living thing.

frugivore

an animal that mainly eats fruit

herbivore

An animal that eats mainly plants or parts of plants.

island endemic

animals that live only on an island or set of islands.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

nomadic

generally wanders from place to place, usually within a well-defined range.

polarized light

light waves that are oriented in particular direction. For example, light reflected off of water has waves vibrating horizontally. Some animals, such as bees, can detect which way light is polarized and use that information. People cannot, unless they use special equipment.

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

polygynous

having more than one female as a mate at one time

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

terrestrial

Living on the ground.

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

2004. "Ecology of Pteropus Rufus in Madagascar" (On-line). Lubee Bat Conservancy. Accessed March 15, 2005 at http://www.lubee.org/global-madagascar.aspx.

Bollen, A., L. Van Elsacker. 2002. Feeding Ecology of Pteropus rufus (Pteropodidae) in the littoral forest of Sainte Luce, SE Madagascar. Acta Chiropterologica, 4/1: 33-47.

Goodman, S. 1989. Madagascar Harrier Hawk (Polyboroides radiatus) preying on flying fox (Pyeropus rufus). Ostrich, 62: 215.

Grzimek, B., F. Main. 1990. Chiroptera. Pp. 436-631 in S Parker, ed. Grzimek's Encyclopedia of Mammals, Vol. 1, Frist Edition. New York: McGraw-Hill Publishing Company.

Hutcheon, J. 1997. Tracking Bats at Ankarana. BATS, 15/1: 14-16.

Long, E., P. Racey, G. Iason. 2001. The nutritional ecology of Pteropus rufus in S.E. Madagascar.

Bat Reseach News
, 42/3: 108. Accessed March 08, 2005 at http://info.bio.sunysb.edu/rano.biodiv/.

O'Connor, T., S. Wing, P. Riger. 2005. "American Zoo and Aquarium Association" (On-line). Parc Ivoloina Bat Education Program. Accessed March 21, 2005 at http://www.aza.org/Action/index.cfm?page=view&id=141.

Williams, G. 2001. "Pteropus rufus Madagascar Flying Fox" (On-line). Accessed March 04, 2005 at http://info.bio.sunysb.edu/rano.biodiv/Mammals/Pteropus-rufus/.

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