The genus Pteropus is also known as flying foxes. It is further divided into 17 species. Scientists have not been able find out Pteropus fossils in (large numbers) to know its evolution precisely due to the delicate structure of these bats. However the available fossil record suggests that flying foxes may have emerged during the early Miocene period in the Australo-Pacific. Acerodon are the closest relatives of flying foxes as they are same in size and morphology to Pteropus.
Flying Fox Bat Facts
Physical Characteristics
- Flying foxes are the largest bats species with the weight of up to 3.5 lb (1.6 kg).
- The Head and body length measures up to 6.7–16 in (17–41 cm); and forearm are 3.3–9 in (8.5–23 cm) long.
- They have a wingspan of up to 6 ft (1.8 m).
- Flying foxes have dog-like facial appearance.
- Pteropus display grayish brown to black color with the dense fur.
- They have yellow to grayish yellow mantle (covering portions of the neck, upper shoulders and the head). Spectacled flying fox has a light ring around its eyes.
- Flying foxes have small external ears and they do not have a tail.
- The second and third fingers move independently and a claw is present on the thumb.
- Pteropus have large protruding eyes. These forward-facing eyes are adapted to both day vision and nocturnal. Thanks to these eyes that allow these bats to recognize light colors and also aid in searching for food sources.
Distribution
- Flying fox are normally found in the islands of Pacific and Indian Oceans, ranging from Madagascar north to the Maldives, across Indonesia, Sri Lanka and finally into the middle Pacific covering islands of Tonga, Samoa, and Caroline.
- They inhabit as far as Cook Islands. Pteropus also lives in Pakistan, Southeast Asia, across India to Australia.
Habitat
Flying foxes make homes in a variety of habitats in the tropical coastal areas including mangrove forests, lowland dry forests, occasionally caves, secondary and primary growth rainforest. Many species roost high above the canopy in a ridge of growing trees.
Behavior
- Flying foxes are likely to be most active at night and in the late hours of evening.
- During daytime many of them roost in trees while the larger species gather in large groups known as ‘camps’. A group may consist of few dozen to 250,000 individuals.
- These bats hang from branches upside down by one or more feet and their wings are wrapped around their bodies. While in camps flying foxes do move around to carry out some sort of activity.
- At dusk, when they are about to fly, bats flap their wings in order to bring their bodies parallel to the ground—after which they release the branch and begin flight.
- Flying foxes do not migrate but seasonally—depends on the availability of food sources. They are not known to migrate long distances as they merely travel between summer and winter roosts when fruits are ready to be fed on. Flying foxes typically travel 30 miles (50 km) to make it to the feeding site, whereas island foxes may migrate to the neighboring islands. They may or may not use the same nesting site.
- They produce sounds in the range of 4–6 kHz. These vocalizations are vital for mating, territorial disputes, interaction with infants, and feeding. Gray-headed flying fox (P. poliocephalus) produces at least 30 different kinds of calls.
Feeding Diet and Ecology
- Flying fox likes to feed on nectar, pollen, and fruits. Thanks to its advanced senses of vision and smell, bats can locate food easily. Like many fruit bats, flying foxes do not navigate themselves using echolocation. They use the optimal foraging in order to go out to feed.
- Once they get to the food, flying foxes will take it to a roost while hanging from a branch with fruit on one foot. Bats obtain juice from these fruits which makes up most of their diet. They compress the fruit pulp against the palate of the mouth, separating the seeds and the pulp and finally swallowing the juice.
- If they find pulp soft enough to eat they will also consume it otherwise pulp is left over.
- Flying foxes often skim the water surface and drink while traveling to a feeding location. A few bats acquire seawater in order to take in minerals that are not found in food sources.
- Pteropus seems to have developed a certain relationship with various plants within their habitat. There are some trees and fruits that are adept to attract fruit bats. Of these trees some have a strong smell (mangos, Mangfiera indiaca) while others are lightly colored (sea almond trees, Terminalia catappa). Flying foxes particularly feed on durian (Durio zibethines)—a tree that blooms only at night.
Reproductive Biology
- Flying foxes begin to form camps in summer especially when fruits and blossoms are ready to mature. It is only at this time that mating occurs as most bats form harms (small groups).
- Male bats will become highly territorial over the females. They mark their territory with the scent gland.
- Female bats breed seasonally and they produce only one young each year. They start breeding at two years of age. Mating occurs from February to April.
- The young are born from September to November.
- Lactation lasts about six weeks while the rest of the time females look after their young.
- The gestation period lasts six months. The female normally gives birth during the day and the birth process may last up to several hours.
- The mother will fly with her pup for about 2 – 3 weeks.
- The ear flaps of the young are down, eyes closed, and it has a light fur.
- The mother will wrap pup with her wings to keep it warm.
- After three weeks the mother leaves the young as now it is too heavy to be carried alongside mother. The mother still recognizes her pup (by its unique vocalizations) when she returns. The young will form its small groups by January and February.
Conservation Status
- Perhaps the major cause that leads to the decline in flying fox bats’ population is deforestation. Gone are the days when these bats could enjoy wide habitats in primary forests. Making things worse the logging activity prevents the growth of new canopy, cutting of large forest leaves make forest susceptible to the tropical storms.
- Humans have converted a large area of mangrove swamps into shrimp farms which has left a devastating effect on few bats species. Pohnpei flying fox (P. molossinus) is one such species.
- Some of the bats species are declining on the ground of illegal wildlife trading
. Often these bats are considered as agricultural pests especially for orchards. Moreover, the introduction of brown snake (Boiga irregularis) in Guam in 1940s led to the population of decline since. Other predators such owls and falcons are also responsible for this much reduction.
IUCN Red List
- Critically Endangered 7 Species
- Endangered 3 Species
- Vulnerable 16 Species
- Lower Risk/Near Threatened 3 Species
- Data Deficient 2 Species
- Extinct 5 Species
Resources
Books
Altringham, John D. Bats, Biology, and Behavior. New York: Oxford University Press, 1996.
Bonnacorso, Frank J. Bats of Papua New Guinea. Chicago: University of Chicago Press, 1998.
Buchmann, Stephen L., and Gary Paul Nabhan. The Forgotten Pollinators. Washington, DC: Island Press, 1997.
Crichton., Elizabeth G., and Phillip H. Krutzsch, eds. Reproductive Biology of Bats. New York: Academic Press, 2000.
Hall, Leslie, and Greg Richards. Flying Foxes, Fruit and Blossom Bats of Australia. Malabar, FL: Krieger Publishing Company, 2000.
Periodicals
Banack, Sandra Anne. “Diet Selection and Resource Use by Flying Foxes (Genus Pteropus).” Ecology 79 (1998): 1949–1967.
Fujita, Marty. “Flying Foxes and Economics.” Bats 6, no. 1 (1998): 49.
Other
“Family Pteropodidae.” University of Michigan Animal Diversity Web. [23 June 2003]. <http://animaldiversity.ummz.umich. edu>.
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