Large Flying Fox (Pteropus vampyrus): Giant Bat Facts

What is a flying fox?

Flying foxes are large bats in the genus Pteropus, part of the Old World fruit bat family (Pteropodidae), also called megabats. They get their name from their fox-like faces, with long muzzles, big dark eyes and pointed ears. There are around 60 species of flying fox, found from Madagascar and South Asia to Australia and the Pacific islands.

The large flying fox is also called the greater flying fox, Malayan flying fox or kalong. The species was described by Carl Linnaeus in 1758 from a specimen collected on Java. He named it vampyrus because large tropical bats were then wrongly believed to suck blood. In fact, the only blood-feeding bats live in the Americas, like the common vampire bat.

What does the large flying fox look like?

The large flying fox has a dog-like head, large forward-facing eyes and small, pointed ears. It has no tail. Its body fur is long and woolly, while the mantle across the shoulders is often paler, ranging from dull buff to orange-yellow. The head may be reddish, orange or blackish, and the underside is usually dark brown.

The wings are made of thin, almost hairless skin stretched between greatly lengthened finger bones. They are fairly short and rounded for such a big bat, which allows slow, maneuverable flight around fruit trees. Each wing carries a claw on the thumb and, unlike most small bats, a second claw on the index finger, both used for clambering through branches.

Males are larger than females and have thicker, stiffer fur. Young bats are a duller grayish brown.

How big is the large flying fox?

Only a few other bats rival it in size, notably the giant golden-crowned flying fox of the Philippines and the Indian flying fox. See What is the biggest bat in the world? for the full ranking.

Where does the large flying fox live?

The large flying fox lives in Southeast Asia, from southern Myanmar, southern Thailand and southern Vietnam through the Malay Peninsula and Singapore to the Philippines and the islands of Indonesia, including Sumatra, Java, Borneo and Timor.

It favors lowland and coastal areas, roosting in mangroves, swamp forest, coconut groves and tall trees in primary and secondary forest. It has been recorded up to about 1,370 m (4,490 ft) above sea level. At night it visits orchards and gardens as well as forest to feed.

What does the large flying fox eat?

The large flying fox is a herbivore that feeds on fruit, nectar, pollen and flowers. When all are available, it seems to prefer flowers and nectar. Its foods include the flowers of coconut palms and durian trees and fruits such as figs, rambutan, langsat, mango and banana.

It eats fruit in a careful way: it slices the skin with its teeth, presses the soft pulp against the roof of its mouth, swallows the juice and spits out most of the fiber. It laps nectar with a long tongue, often without damaging the flower. A large flying fox can eat about half its body weight in food in a day. Learn more in What do fruit bats eat?.

By carrying pollen from flower to flower and dropping seeds far from the parent tree, the large flying fox is an important pollinator and seed disperser for tropical forests and some crops.

Can flying foxes see in the dark?

Yes. Unlike most small bats, the large flying fox does not use echolocation. Instead it relies on excellent night vision and a keen sense of smell. Its eyes are about 12 mm (0.5 in) across, the largest measured among fruit bats in one comparative study. Its retina is packed with light-sensitive rod cells, and flying foxes also have cone cells that give them some color vision.

Smell helps it find ripe fruit and open flowers from a distance. These senses explain why the old saying “blind as a bat” is wrong; read more in Are bats blind?.

Behavior and roosting

Large flying foxes are highly social. By day they hang upside down in roost trees, often in groups of hundreds or thousands. Colonies of 10,000–20,000 have been reported. Roosts are noisy places, with constant squabbling over the best branches. When it gets hot, the bats fan themselves with their wings, lick their fur or pant to cool down.

At dusk they fly out in a long, scattered stream to feed, sometimes traveling up to about 50 km (31 mi) in a night. They usually fly silently but become very noisy at feeding trees, where they defend flowering branches by spreading their wings and growling. Satellite tracking has shown that some adult males move hundreds of kilometers between roosts in a year.

When they reach a feeding tree, flying foxes often circle it before landing. They usually land upright on the tips of branches, then swing into a head-down position to feed. Like other bats, they hang by their feet with little effort, because the tendons of the toes lock the claws in place under the body’s own weight.

The same roost trees may be used for many years, and the bats’ sharp claws can strip the branches of bark and leaves. In the Philippines, large flying foxes often share roosts with the endangered giant golden-crowned flying fox. Large dominant males hold the best roosting spots and guard small groups of females, mating with up to about ten of them.

Reproduction and life cycle

Large flying foxes usually breed once a year, and the female gives birth to a single pup, rarely two. The timing differs from place to place: in Peninsular Malaysia most pregnancies are from November to January, while births peak around March and April in Thailand and April and May in the Philippines. Pregnancy lasts roughly 140–190 days, or about five to six months.

A newborn weighs about 130 g (4.6 oz), a large baby relative to its mother. For the first few days the mother carries the pup clinging to her belly as she flies, then leaves it at the roost while she feeds. Young are weaned at about two to three months and become mature at about two years old. Wild large flying foxes are thought to live around 15 years, and captive animals have reportedly lived much longer.

Threats and conservation status

The IUCN Red List classifies the large flying fox as Endangered (assessment published in 2022), with a decreasing population. It is also listed on CITES Appendix II, which controls international trade.

The main threats are:

• Hunting. Flying foxes are hunted for meat and for traditional medicine in many parts of their range. In Peninsular Malaysia, licenses issued from 2002 to 2006 allowed about 22,000 bats a year to be killed, and a 2009 modeling study warned that this level of hunting could wipe out the local population within decades.
• Habitat loss. Clearing of lowland forest and mangroves removes roosts and feeding trees.
• Conflict with farmers. Bats that raid fruit orchards are often killed.

Because flying foxes breed slowly, with only one pup a year, their populations recover slowly from losses. Natural predators such as large birds of prey and pythons take some bats, but people are by far the biggest threat.

Flying foxes and people

Large flying foxes are natural carriers of Nipah virus, which caused a serious outbreak in pigs and people in Malaysia in 1998–1999. The bats themselves are not aggressive, but wild bats should never be touched or handled. If anyone is bitten or scratched by a bat, seek emergency medical help immediately.

At the same time, flying foxes are valuable to people. They pollinate durian flowers along with other nectar-feeding bats, spread the seeds of many forest trees and help degraded land regrow. Their dusk fly-outs over the islands of Komodo National Park and elsewhere attract visitors from around the world. To learn how bats fit among other mammals, see Are bats mammals?.

Myths and facts

Myth: flying foxes are a kind of fox. They are bats, not dogs or foxes. The name comes only from their fox-like faces and reddish fur. Bats form their own order of mammals, Chiroptera, and they are not rodents either.

Myth: big bats drink blood. None of the world’s flying foxes or other Old World fruit bats feed on blood. Only three small species in Central and South America do, and all of them weigh less than 60 g (2 oz).

Myth: bats are blind. The large flying fox has some of the biggest eyes of any bat and sees very well in dim light, although its vision in bright daylight is poorer than ours.

Fact: they are among the largest bats ever recorded. With a wingspan of up to 1.5 m (4 ft 11 in), a large flying fox can spread its wings wider than a common buzzard, yet it weighs only about as much as a small rabbit.