The Large or Malayan Flying Fox - A Fascinating Bat of Asia
The Impressive Flying Fox
Flying foxes are fascinating bats. As their name suggests, they look somewhat like foxes which have developed wings and taken to the air. They have pointed, fox-like faces with large eyes and small ears. The large or Malayan flying fox of Southeast Asia is a giant of the bat world and has a wingspan of up to six feet. In North America, the term "flying fox" often refers to this animal.
Flying foxes belong to the family Pteropodidae. At least 170 species exist, the exact number depending on the classification scheme that's used. They are also known as fruit bats, since their diet consists of fruits and other plant parts, and as megabats, since their family contains the largest bats in the world. Not all megabats are large, however. Unlike other bats (the microbats), flying foxes don't use echolocation to hunt for their prey. Instead, they use their excellent senses of sight and smell to help them find their food and escape from danger.
The large or Malayan flying fox (Pteropus vampyrus) is often considered to be the largest bat in the world, although sometimes other bats are given this honour. Its population is classified as near threatened by the International Union for Conservation of Nature. In some parts of the bat's distribution its numbers are decreasing rapidly due to hunting and habitat loss.
Structure of a Bat Wing
Bats - Mammals That Can Fly
Like other mammals, including humans, bats have hair on their body and make milk for their young. Bats are the only mammals that can fly, however. Other mammals that appear to fly, such as flying squirrels, actually glide. Bats flap their wings to propel themselves through the air. The wings are made of webs of skin supported by hand, arm and leg bones. Bats either have no tail or have a tiny, non-functional remnant of a tail.
Most bats are nocturnal, sleeping in a protected place during the day and becoming active at night. Microbats are able to carry out a process called echolocation, which helps them find their prey. Most of these bats eat insects. When they're hunting, they emit ultrasonic sound waves though their nose or mouth. "Ultrasonic" sounds are too high for us to hear. The sound waves bounce off the prey and return to the bats, enabling them to detect the presence and position of the prey. In general, megabats can't carry out echolocation. The Egyptian fruit bat is an exception. It uses a simple type of echolocation to navigate in the dark.
Bat Anatomy - Skeleton and Wings
A bat's skeleton has some special adaptations to allow the animal to fly. The thin arm bones bend at the elbows and end in very long and skinny finger bones. The arms and the fingers support a membrane made of skin, which forms a wing.
The thumb is shorter than the other fingers and is free of wing. A curved claw is present at the tip of each thumb. This claw enables the bat to grab hold of supporting objects as it climbs or travels around with its wings closed.
The wings extend to the back legs. The feet have clawed toes, which help the bat move and are used to cling to a support when the bat is hanging upside down. Often a bat hangs by just one foot. The knees point backwards when they're bent. Some bats move rather clumsily on land, but all are graceful fliers.
A Bat Skeleton
Bat Roosts and Camps
The majority of bats hunt for their food during the night and sleep in their roost during the day. A "roost" is a place where bats live. When bats are present in their roost they are said to be "roosting". Common sites for roosts are caves, but bats also roost in tree canopies and cavities, under bridges or roofs, in abandoned mines, basements or attics, in rock crevices and in wall cavities. When many bats use the same roost, the area is sometimes called a camp.
The little red flying fox of Australia has been known to form camps containing over a million bats. As the bats stream out of their camp they produce a very impressive sight. Large roosts containing many bats are thought to provide benefits such as increased warmth in the roost, better protection of the babies and predator confusion created by a huge number of bats flying at the same time.
A Flying Fox Moving Around With the Help of its Thumb Claws
The Large, Malayan or Malaysian Flying Fox
The large flying fox is found throughout Southeast Asia in forests and mangroves. Its wings are made of two layers of skin. The wingspan is usually about five feet, but sometimes reaches an amazing width of six feet. The bat weighs up to 2.4 pounds.
The large flying fox has large eyes, pointed ears and no tail. It's usually black, brown, red-brown or orange-brown in colour. The chest may be bright orange, however, and the area between the shoulders may be orange or yellow. The hair on the bat's back is short and quite stiff, while the hair on its undersurface is longer and woolly.
The Large Flying Fox - A Megabat
Although the species name of the large flying fox ("vampyrus") may remind people of blood-drinking vampire bats, the flying fox eats plants. The bat is nocturnal and forages for fruit at night, starting at sunset and returning at dawn. It also eats flowers, pollen and nectar. It has a long tongue, which helps it reach the nectar inside a flower. Its teeth are adapted to cut through the tough outer covering of fruits.
The large flying fox plays an important role in its ecosystem. Flower pollen may become trapped on the bat's fur as it feeds and then fall off when the bat visits another flower. In this way the bat acts as a pollinator. The bat also helps to distributes the seeds of fruits. It squeezes fruits in its mouth to extract the juice and then spits out the dried pulp and the seeds. Since bats may carry fruit to a new area before they eat it, the seeds can germinate far away from their parent flower. Any seeds that are swallowed pass through the bat's digestive tract unharmed and are released into a new habitat in the feces.
Large flying floxes may fly more than thirty miles from their roost in order to find food. Unfortunately, they sometimes visit cultivated fruit trees to feed, which brings them into conflict with humans.
A Captive Large Flying Fox
During the day the large flying fox roosts in large communities in the tree tops. There are hundreds or even thousands of bats in most roosts. The branches in the area are stripped of their leaves and bark by the bats' claws. Bats sometimes compete for the best place to hang. They may spread their wings, strike other bats with their thumb claws and growl or shriek to express territoriality. Flying foxes produce a variety of vocalizations and can be very noisy, especially when feeding.
The bats sleep with their wings wrapped around their body. If they get too hot they open their wings to fan themselves. They may also lick their fur so that the evaporation of saliva cools them down. Occasionally they may leave the roost for a short flight. When they need to defecate or urinate, they turn upside down (from their point of view). They hang on to their support with their thumbs instead of their toes so that the waste falls to the ground and not on to their bodies.
Reproduction and Lifespan
A male large flying fox mates with several females. The gestation period is five or six months. Usually only one baby is born per female. Occasionally, twins are produced. The babies, or pups, have light colored haiir, which darkens as they mature. Females in a group produce their pups at the same time.
The young pup attaches itself to its mother's chest and is carried around by her, even while she's flying. After the first few days of its life, however, the mother leaves her pup in the roost while she forages for food. The pups suckle for two to three months. The animals seem to live for about fifteen years in the wild. They have lived for as long as thirty years in captivity, however.
Flying Foxes in a Zoo Cave
The IUCN Red List
The IUCN (International Union for Conservation of Nature) monitors the populations of flying foxes and other animals. It maintains a list of animal species - the Red List - and uses the following categories to classify the population status of each species. In general, the categories range from the least serious state to the most serious. The "Not Evaluated" and "Data Deficient" categories could mean that a popuation is in trouble, however. The large flying fox is classified in the Near Threatened category.
- Not Evaluated
- Data Deficient
- Least Concern
- Near Threatened
- Critically Endangered
- Extinct in the Wild
The Black Flying Fox or Pteropus alecto in Australia
Population Status of the Large Flying Fox
The large flying fox faces a number of problems. In many places its forest habitat is being cleared for human use. In some areas it's treated as an agricultural pest and is shot or poisoned. It's widely hunted for food and sport, often legally. Illegal hunting also occurs. In addition, the bat is killed for its fat, which is used in traditional medicine.
There are laws protecting the bat in some parts of its range, but they aren't always enforced. The animal flies long distances during foraging and during migration to new roosts. It often travels over national boundaries, so international laws are needed.
The IUCN says that although the status of the large flying fox population is "near threatened" at the moment, the animal is close to "vulnerable" in status. Some conservationists think that in certain parts of its range the bat could become extinct within the lifetimes of people living today. It would be a great shame if this magnificent animal disappeared from the Earth.
© 2013 Linda Crampton