Flying-foxes (also called fruit bats) are members of a large group of mammals called BATS. There are microbats and megabats. Bats are the only group of mammals capable of sustained flight.
There are four recognized species of megabats on mainland Australia: The Little Red, Grey-headed, Black and Spectacled Flying-foxes. They have a very keen sense of smell and good eyesight, both of which are needed to locate their food during the night. Microbats use echolocation – a bit like hearing with pictures, they still use their eyes to see too. Flying foxes and microbats are protected native Australian species, it is illegal to cause them harm. Flying-foxes are usually found in coastal areas of melaleuca and casuarina swamps, mangroves, heath, dry and wet eucalypt forests, woodlands and rainforests. The little red flying fox can also be found further inland in arid and semi-arid areas. Flying-foxes all over Australia are increasingly on the move searching for new or existing food resources – their favorite foods, nectar and pollen from our native trees and plants.
Flying foxes only have one live young per year, which compared to other animals of their size, is a very low birth rate. The little red gives birth around April/May whilst the remaining three species give birth around October/November. The mothers carry their babies out each night to forage. The baby clings to the mothers underarm nipple with their mouths and hang onto her waist with their toes. They are carried by their mother for 4-5 weeks until too heavy to carry. The young is then left in the colony or the outlying trees of a colony and wait for their mother to return at dawn. They begin to fly at about 8-10 weeks and feed independently by about 12 weeks.
The bond between mother and baby is very strong, mothers who lose their babies to predators while off foraging will search the place they last saw their baby and continue calling for up to one week later. Females start breeding when they are about 15 months old. Males do not mature until around 3 years of age and they then form either paired or harem groups during the mating season. It is during this season that flying-foxes tend to be the noisiest due to the defending of territories. It is also during this time that the campsite appears to emit the strongest odor due to secretions from the male scent glands at his shoulders. He will rub this perfume on branches to mark his territory. The higher a male hangs in the tree and the smellier he is the more attractive he is to a mate. You need to think about this smell, it’s musky and sometimes strong after rain but it is not as bad as the smell of stepping in dog poo!
Campsites are very important to the survival of flying-foxes, as this is where they are born, grow, form relationships and learn to survive. Campsites may be permanently or temporarily occupied throughout the year depending on the season and availability of food. Flying-foxes only have one live young per year. The Little red gives birth around April/May whilst the remaining three species give birth around October/November. The size of the campsite may also vary during the year, increasing when there is a good food source around or when mothers arrive to give birth to their young. Numbers may also increase if there is little food elsewhere or another campsite has been disturbed or destroyed. A decrease in numbers usually indicates poor food in the area or disturbance of a campsite.
Flying-foxes need campsites made up of large areas so that they can circulate with the site according to the defoliation of the trees in which they roost. Currently many sites sustain more damage due to the small areas that the flying-foxes are now confined to and due to their staying longer because of lack of food elsewhere or due to the extensive distances that now exist between campsites. Campsites are usually located on rivers, creeks or near large bodies of water, which provide both fresh water, and a navigation device when coming home at night.
Flying-foxes are very fond of the nectar, pollen and fruit of native Australian forest trees such as eucalypts, Melaleuca, Banksia, Lily pilly and Moreton bay figs. Although they do consume cultivated fruit such as peaches, mangoes and pawpaw, they only do so when their native food is scarce.
Flying-foxes generally migrate from one area to another depending on the amount of food available. Unfortunately, with land clearing for agriculture and urban development, the flying foxes have very few areas in which they can migrate to once flowering/fruiting ceases in another area and so find it necessary to sometimes eat cultivated fruit.
The food that flying foxes eat and the method by which they forage and process that food has lead to the flying fox being one of the most efficient pollinators and seed dispersers of native Australian forest trees. As they move amongst the flowers of Eucalypts or Melaleuca searching for nectar, large amounts of pollen attach to their fur. When they fly to the next tree, which may be several kilometers away, this pollen is deposited on the stigma of awaiting flowers. Such transport of pollen is very important for trees such as eucalypts as they rely on cross-pollination, i.e. pollen coming in from other trees which are a substantial distance away. In the case of seed dispersal, many seeds will not grow unless they are a certain distance away from the parent tree. Flying foxes carry out seed dispersal by one of three methods: 1) carrying the fruit away and dropping it accidentally, 2) carrying the fruit away, eating the flesh and spitting out the seeds and 3) consuming the fruit and seeds but passing the seeds through the gut. Flying foxes have a very short digestive tract, thus seeds swallowed are not digested but pass through the gut within 12-34 minutes.
Flying foxes have recently been associated with two potentially pathogenic viruses: Hendra or Equine Morbillivirus (EMV) and Australian Bat Lyssavirus (ABLV).
Hendra virus is not contagious from bat to human, it may require a mediator, such as horses in the case of the Australian incidents. More research needs to be done as the suspected transmission mode from bats to horses is not known. Another animal may prove to be the vector.
With regard to Lyssavirus, only a small proportion of the bat population may have the virus, it is very rare. Do not risk infection to yourself and the death of the bat. Please – do not handle bats – seek help immediately. If you do find an injured bat alone during the day, it needs help, whether it is a flying fox or a microbat, do not pick it up, like any wild animal it may bite when frightened or injured. Call Bat Care Brisbane. If bitten or scratched, wash the area immediately and thoroughly with soap and warm water, seek medical attention as soon as possible.
Flying fox numbers have decreased dramatically over the last 50 years due to loss of habitat, uncontrolled killing at orchards and poor management procedures. With changes in climatic conditions our forests are flowering at different times, flowering with no nectar production or not flowering at all. There are also heat events where thousand of young may perish when temperatures rise over 40 degrees C.
We know very little about bat behaviour yet there is little research into their decline nationally. If governments and communities do not work to preserve their populations now Australian forests, our hardwood and rainforests will decline and our entire ecosystem will be under threat.
Recovery teams have now been formed for both the grey-headed and the spectacled flying fox in an attempt to bring their numbers back from such dangerous levels. These teams are headed by the Queensland Environmental Protection Agency, New South Wales Department of Environment and Conservation, and the Department of Environment and Heritage.
Information by Dr. Patrina Birt