Megabats (sub-order Megachiroptera)

Megabats are large bats that navigate by sight and smell and feed on plant products. They can be found in Africa, the Middle East, Southern Asia, Australia and many islands. In Australia there are 12 megabat species. These include flying-foxes, tube-nosed fruit bats and blossom bats. Of the 8 species of flying-fox there are four widespread species occurring on the mainland of Australia. These are the Black, the Spectacled, the Grey-headed and the Little Red Flying-foxes. The first three of these have similar habits and lifestyle but are found in different parts of Australia, their ranges overlapping in part. The Little Red Flying-fox is smaller and gives birth at a different time to the others and tends to follow the flowering of the eucalypts inland, moving to the coast irregularly.

Grey-headed Flying-foxes (Pteropus poliocephalus)
The next section is based on our knowledge of the Grey-headed flying-fox, which is found in southern Queensland, NSW and Victoria. It is endemic to Australia.

Is a flying-fox a bat?
Yes. Flying-foxes are sometimes called fruit bats but many of them eat parts of plants other than fruit, especially pollen and nectar.

What do flying-foxes do at night?
Flying-foxes leave their camp soon after sunset to feed during the night, even in rainy weather. They return to camp before sunrise.

What do flying-foxes eat?
Their main source of food is nectar and pollen from the flowers of native trees, such as the many species of eucalyptus, as well as turpentines, paperbarks, banksias. They also eat fruit from many rainforest plants, such as figs and lilly pilly. They chew the fruit to extract the juice and spit out the fibre and drop the big seeds. They swallow the juice and some small seeds up to 4 mm in diameter. They also chew leaves of plants such as mangroves and figs. At times they feed on fruit and flowers of plants brought into Australia from other parts of the world.

Why are flying-foxes important?
They move pollen and seeds over vast areas of forest. The pollen is carried on their fur between flowering trees which can be many kilometres apart. Many Australian trees, especially eucalypts, need pollen from another tree of the same species to make fertile seed. Rainforest seeds are carried away from parent trees which gives them a chance to germinate and grow. Flying-foxes are essential in maintaining many ecosystems because they are able to move pollen and seeds over long distances and across cleared ground, thus linking patches of native vegetation. Birds and insects don't fly the long distances needed. The clearing of native vegetation in the last two centuries has removed much of it and has left the remainder scattered in isolated patches.

How long do Grey-headed flying-foxes take to digest their food? Why is this important?
Flying-foxes have a very short intestine and absorb their mostly liquid diet very rapidly. Average time from mouth to anus (doing a poo) is about 20 minutes although some material takes up to an hour. This is important for seed dispersal because the small seeds contained in the faeces (poo) fall and germinate in new areas leading to new trees and vines.

How fast do flying-foxes fly?
Grey-headed Flying-foxes fly about 25 -30 km per hour. Some were observed in a wind tunnel where their average flight speed for distance travelling was recorded as 7m per second (25 km/hr). In the wind tunnel test a greyheaded flying-fox maintained a speed of 26 km/hr for 4 hours. Flying-foxes also use the wind to travel long distances and have been recorded at speeds of 50 km per hour.

How far do flying-foxes fly in one night?
The majority of flying-foxes feed during the night within a radius of 30 km from their camp, however, when feeding on blossom may travel up to 100 km during the night. Some feed in the same place on successive nights. This information was obtained by radio-tracking individual flying-foxes.

How well do flying-foxes see?
Their acute eye-sight enables them to navigate accurately and to find food at night. Many of their food plants have white blossom making them easy to see when flying above the trees at night. In daylight they are also able to fly and land on branches within the camp and use sight during social interactions in bright sunlight.

How important is smell to a flying-fox?
Flying-foxes use their excellent sense of smell to locate nectar and ripe fruit.

What do flying-foxes do in the daytime?
Flying-foxes are social animals. They roost together in the tops of trees. During the day they spend some time sleeping, often hanging by one foot, with their wings wrapped around their body. They also spend many hours grooming themselves, squabbling noisily and fanning themselves when hot. Females care for their young. The area they occupy is called a camp or a colony. A camp may contain a few hundred to tens of thousands of flying-foxes. Sometimes the camp is empty if food is not available nearby. Most of these camps have been in use for more than 100 years.

What predators do flying-foxes have?
Predators known to eat flying-foxes include carpet pythons, goannas, sea-eagles and the Powerful Owl. Currawongs and ravens are known to attack flying-foxes found on their own in the daytime. These predators do not significantly reduce the overall flying-fox population. The most likely victims are the young, the sick or old. The numbers taken are small relative to the flying-fox population. Predators contribute to the health of a population by removing the least fit individuals. Humans and their technology are responsible for more flying-fox deaths than natural predators - removing habitat by clearing native vegetation, shooting, and electrocution on power lines.

What sounds do flying-foxes make?
Flying-foxes are social animals and make a wide range of calls. These include contact calls, chirps and squabbles, searching calls by mother flying-foxes seeking their young when returning to the colony, and a range of mating and warning calls. At night feeding flying-foxes are often heard in flowering or fruiting trees as they compete for food. Australian flying-foxes do not echo-locate; that is, they do not use sound to locate or navigate.

What do flying-foxes hear?
Flying-foxes have a simple external ear, unlike the complex ears of micro-bats. The part of the brain which controls hearing is small in flying-foxes compared to that in micro-bats. This suggests that hearing is of minor importance to flying-foxes compared with other senses.

How well do flying-foxes see?
Flying-foxes see very well during the day and much better than humans at night. They have relatively large eyes in the front of their skull.

How do flying-foxes recognise each other?
They recognise each other by sight and smell. Flying-foxes have scent glands on their shoulders. This scent is spread over their body while grooming. They sniff each other during social interactions. Males rub their scent glands onto tree branches in the colony to mark a territory. Mothers recognise their young by their calls and by their smell.

How far do flying-foxes move during the year?
Flying-fox numbers in a camp increase and decrease throughout the year, depending on the availability of food. The flowering of many species occurs irregularly in different areas and different times of the year, governed mainly by variations in weather. Radio-tracking of grey-headed flying-foxes found that in 1990 one moved from Grafton to feed on the flowers of spotted gum near Narooma - about 800 km south and another flew from Lismore to Bundaberg in Queensland, about 400 km to feed on lemon-scented gum. Hand-reared juvenile flying-foxes were tracked between Gordon, Sydney Botanic Gardens and Cabramatta Creek and some found 310 km north and 279 km south in April and May. vi A minimum distance of 978 km was recorded when one was marked on the thumb by a numbered band and released in Lismore on 31/8/91 and was reported electrocuted at Bombala on 12/2/92. By tracking a few individual flying-foxes by satellite it has been found that individuals travel great distances, for example, one moved from Melbourne to Mallacoota then north along the coast, stopping at Ulladulla and Jamberoo, then to Sydney, where it moved between several more camps.

How long do flying-foxes live?
Little is known about what age the majority of flying-foxes reach in the wild. Records of banded flying-foxes indicate that some live for to 12 years in the wild. The oldest captive educational Grey-headed flying-fox, cared for by Ku-ring-gai Bat Conservation Society, was born in 1978 and died of old age in 2000 - aged 22. Several others have lived to a similar age in captivity. Natural disasters such as the high temperatures, over 40 C, and low humidity which occurred in Sydney in January 2002, killed thousands of flying-foxes of all ages.

How do flying-foxes keep clean?
Flying-foxes groom their fur frequently with their claws and lick their wings. They urinate on themselves to wash and in the summer they urinate on themselves, then fan their wings to cool down.

Do flying-foxes have parasites?
Like all mammals bats are hosts to tiny parasites that live much of their life cycle on the animal. Bat flies are wingless flies, only a few millimetres long, which are adapted to avoid being groomed out of the fur by the bat or blown off during flight. They feed on the bat's blood. They are species specific and cannot live on other mammals such as humans. Flying-foxes also have internal parasites which have adapted to live in the flying-fox population without causing undue illness in their hosts except during times of food shortage. One is a worm (Toxocara pteropodis), which is transferred with the milk from mother to young and from young to adult through faeces on branches. Again this organism cannot live in humans. Occasionally flying-foxes are hosts to ticks and mites. In Queensland a number of Spectacled Flying-foxes die each year from tick poisoning.

Do flying-foxes drink?
Yes. They swoop down to belly-dip in rivers and dams. They then land on trees and lick the water from their belly fur. They also lick dew from leaves.

Where do they get protein?
Pollen is the major source of protein, much of it licked from its fur while the flyingfox is grooming. Protein is used to build muscle tissue. Pollen grains break open in the gut so that the contents are absorbed. Some native fruits such as figs are also a source of valuable protein.

Where do flying-foxes get carbohydrate?
Nectar and fruit juice provide the carbohydrates - sugars. These provide energy. Some species of eucalypts, especially bloodwoods (Corymbia spp) are known to produce most of their nectar at night.

How many teeth does a flying-fox have?
34
Their dental formula:
upper tooth row: incisors = 2-2, canines = 1-1, premolars = 3-3, molars = 2-2
lower tooth row: incisors = 2-2, canines = 1-1, premolars = 3-3, molars = 3-3

When and where do flying-foxes give birth?
After becoming pregnant in Autumn (March-April), they give birth in Spring (mainly October-November). This is a gestation period of about 6 months. They give birth in the tree tops, usually in the colony.

How many babies do they have?
One baby is born to each female. The baby is born furred and with its eyes open. It weighs about 80 grams at birth although birth weight varies according to the availability of food for the mother during her pregnancy.

How do flying-fox mothers care for their young?
The female has 2 nipples, one on either side of her chest beneath the wingpit. As soon as the baby is born it begins to suckle. Its milk teeth curve backwards so that it can keep a firm hold. She protects her baby with her wings during the daytime. At night when she flies to search for food the baby holds onto its mother, with its mouth around the nipple and with its claws in her fur. The baby is not able to maintain its own body temperature until it is 15 - 17 days old so stays close to its mother. The young are then left in the colony during the night and the mother returns to it before sunrise. In December young begin flying within the camp at night and in January are flying out with the adults to feed. Some are seen still suckling in the daytime in the mating season.

When do flying-foxes mate?
Mating occurs between March and May. Males mark a territory in a tree and defend it from other males during the summer and autumn. They are joined by females, many with young. Males guard several females in their harem. Harems are generally unstable groupings, with the females moving, at will, to other males.

Do they mate for life?
Observations indicate that flying-foxes do not form lifelong relationships.

Is it true that flying-foxes are primates?
The theory that flying-foxes are related to lemurs, lorises, monkeys, apes and man (primates) was proposed by Dr Pettigrew at University of Queensland based on studies of the brain and nerves to the eye. The structure of the brain is more like the primates than the microbats. He has proposed that the megabats and microbats evolved from different ancestors and that the structure of the wings of these two groups of bats has evolved independently (known as convergent evolution).

Why is the grey-headed flying-fox considered a threatened species?
In 2001 the Grey-headed Flying-fox was listed under the State of New South Wales and the Commonwealth of Australia legislation as a vulnerable species. Vulnerable means facing a high risk of extinction in the wild in the near future, unless the factors threatening its survival cease to operate. See the NSW National Parks & Wildlife Grey-headed Flying-fox Species profile at:
http://www.nationalparks.nsw.gov.au/PDFs/tsprofile_greyheaded_flyingfox.pdf
Reports dating back to the 1930s describe sightings of millions of Grey-headed Flying-foxes. Now National Grey-headed Flying-fox counts indicate there are less than 450,000. A 30% decline in the population of this bat in the decade prior to the year 2000 has been documented. Land clearing for agriculture and urban development has removed vast areas of feeding habitat, especially in the coastal areas of Queensland, New South Wales and Victoria as well as on the western slopes of the Great Dividing Range. This has reduced the food options for flying-foxes. Starving flying-foxes have been seen in some areas in recent years. Additional causes of decline are the shooting of flying-foxes by fruit growers to protect their crops from being damaged by flying-foxes, disturbance of roosts, electrocution on electricity wires, entanglement in fine nylon netting over garden fruit trees and on barbed-wire fences.

What is being done to conserve flying-foxes?
The NSW Government has increased the area of native vegetation protected in national parks Private landowners are entering into conservation agreements to protect native vegetation on their properties for the long term, Many commercial fruit growers are now using total exclusion netting to protect their crops from flying-foxes and birds Some banana growers are modifying their bunch bags to prevent flying-foxes from damaging the fruit Garden fruit trees are being protected with netting stretched over a frame Volunteers everywhere are involved in regenerating native habitat through Landcare, Bushcare and Dunecare programs NSW Government is preparing a recovery program for the Grey-headed Flyingfox Flying-foxes in Sydney.

How many flying-fox colonies/camps are there in Sydney?
There are currently three major sites in Sydney:
1. Ku-ring-gai Flying Fox Reserve, Gordon
2. Cabramatta Creek
3. The Sydney Royal Botanic Gardens.
4. Other camps occur in the lower Blue Mountains, Kurnell, Menangle, Yarramundi and Emu Plains (these camps are not always occupied).
In the past flying-foxes were reported to have camped in mangroves on the Georges River, at Dural, at Fox Valley in Wahroonga, in fig trees at Mosman, on Cabramatta Creek and in the eastern suburbs on the Port Jackson side. Grey-headed Flying-foxes have used Ku-ring-gai Flying-fox Reserve at Gordon annually, from the early 1960s, but earlier reports such as 1940s and early in the century suggest that this area has been used, intermittently, for a long time. The numbers in a colony fluctuates according to food availability in the area compared with elsewhere. During the summer peak, the colony at Gordon can contain 60,000 flying-foxes one year and 20,000 the next because of variations in food supply throughout their range.

To see a timeline of flying-fox numbers at the Ku-ring-gai Flying-fox Reserve at Gordon, go to 'Flying-fox Counts at Gordon'

For information on flying-foxes at Cabramatta and the Sydney Royal Botanic Gardens, refer to following websites:

Flying-Fox Group of Cabramatta http://www.fairfieldcity.nsw.gov.au/default.asp?iSubCatID=272&iNavCatID=156

Sydney Royal Botanic Gardens http://www.rbgsyd.gov.au

Can I have one as a pet?
No. Bats are a protected native animal. It is necessary to have a licence from the National Parks and Wildlife Service to care for native animals. To raise an orphan flying-fox you must be a member of a licensed wildlife care group and have specialist training in the care of flying-foxes.

What do I do if I find a bat that appears sick or injured?
Do not touch it In Sydney telephone -
Sydney Wildlife (02) 9413 4300.
or
Wildlife Information and Rescue Service (WIRES) (02) 8977 3333
Wild rehabilitated flying-foxes and hand-reared orphans are released into the camp at Gordon under a protocol approved by NPWS, Ku-ring-gai Council, Ku-ring-gai Bat Conservation Society, Sydney Wildlife and WIRES. For rescue and care of flying-foxes outside Sydney contact local wildlife organisations.

Which trees can I plant to attract flying-foxes?
See list of native plants on which flying-foxes feed. Only plant trees that are found naturally in your area; ask your Local Council for advice.

i. Hall L and Richards G (2000) Flying Foxes, Fruit and Blossom Bats of Australia, University of New South Wales Press.
ii. Altringham J D. (1996) Bats, Biology and Behaviour Oxford University Press
iii. Carpenter R E (1985) Flight physiology of flying foxes, Pteropus poliocephalus Journal of Experimental Biology, 114 pp 619 - 47
iv. Nelson J and Tidemann C Satellite tracking of flying-foxes, Monash University website http://biolsci.dbs.monash.edu.au/labs/flyingfoxes/index.htm
v. Eby P (1995) The biology and management of flying foxes in NSW Species management report No 18, NSW National Parks and Wildlife Service
vi. Augee M and Ford D (1999) Radio-tracking Studies of Grey-headed Flying-foxes, Pteropus poliocephalus, from the Gordon Colony, Sydney.
vii. Eby P and Jones V (2002) A bloke in every port: group composition and gender bias in the migration patterns of grey-headed flying foxes Pteropus poliocephalus, Abstracts, 10th Australasian Bat Society Conference, 2002.
viii. Pettigrew JD (1986) Flying primates? Megabats have the advanced pathway from eye to midbrain, Science, 231

Last modified by KBCS Inc. on 2007/01/14.