BATS - how did we get it so wrong?
Australian Fauna Care

Talk to most people about bats, and they will conjure up images of vampire legends and sinister mysteries. Many people refer to them as vermin, with no value to mankind or the environment. The popular image of bats could not be further from the truth, and it is worth taking the time to learn a few facts.

 A little background information Baby Spectacled Flying-fox, Atherton, Qld
There are about 1100 species of bat, representing about 20% of all classified mammal species. They fall into two suborders: the large "mega" bats and the smaller microbats.  There are around 75 identified species in Australia.

About 75% of bats eat mostly insects. These are the microbats, which includes all the bats that use echo-location.  Most of the rest eat fruit or nectar, and these tend to be the larger megabats. A few microbat species feed from animals other than insects, such as the Australian "Ghost Bat" which feeds on small mammals and there is even an Australian "fishing bat".

The photo above is a baby Spectacled flying-fox (pteropus conspicillatus) in care at the Tolga Bat Hospital in Qld. A member of the larger fruit and nectar-eating bat family, they have large eyes and don't use echo-location.

Bats - not only important, but essential
Lesser Long-eared batMost microbats are insectivorous.  They can catch and eat up to one third of their own body weight in insects. Some species thrive on mosquitoes and a single microbat can clean up over 500 mozzies an hour - that's thousands per night.  It has been estimated that a group of 250 microbats could eat a ton of insects in a year. A 1990 study in the US determined that if bats were to become extinct, the insect population would reach alarming numbers!

The photo on the right is a Lesser Long-Eared microbat (Nyctophilus geoffroyi) recovering in care at Nowra, NSW.

On the other hand, flying-foxes are important pollinators. Studies have shown that not only are they the sole pollinator of certain tree species, but that their long flights and slow digestion means that seed dispersal is more widespread than that performed by insects or birds (important for genetic diversity).

More like us than we know
While they have had to adapt their shape so they can fly,  bats are warm blooded, placental mammals - just like us. Flying-foxes are highly intelligent, have a complex social structure and have a larger range of vocalisations than almost any other mammal. They have a six month gestation period (compare this to nine weeks for a dog). Like us, they usually have one baby at a time, with occasional twins. They carry their babies around with them for about three weeks after they are born, and continue to breast-feed them for up to 6 months.

Who is the real pest?
Media reports over the last few years have been largely critical of bats, focusing on three issues.

  1. Bats carry deadly viruses
    Hand raised Grey-headed Flying foxes almost ready for release - NSWA number of bat species carry potentially serious viruses (so do other animals, including cats). Only two people have ever died from Australian Bat Lyssa Virus, and one of these refused potentially life-saving treatment. Four people have died from Hendra virus, but these were all contracted from horses, which it is believed were infected by bats. The actual risk posed by bats is almost nil. By contrast, humans are responsible for the deaths of hundreds of thousands, if not millions of bats.

  2. Bats destroy fruit orchards
    Flying requires a lot of energy, and as a result, bats need high energy foods. For flying-foxes, their natural diet is based on native fruits and nectar. Carers find that when given the choice, flying-foxes in captivity prefer their natural diet to exotic (introduced) fruits. Human activity has resulted in the destruction of many thousand square kilometres of native vegetation - especially around urban areas. As a result, bats may "raid" orchards when there is no native food available.  Proper netting of orchards can  negate this risk, and also stop birds and the effects of hail on their crops.

  3. Bats set up their camps in populated areas
    There is strong evidence that bats have a very high loyalty to their roosting sites known as camps.  Some are occupied on a permanent basis, and others may be used intermittently. Bats also require a "network" of camps, usually only 50K or so apart - this is an important part of their social structure.  When human activity results in the destruction of their habitat. they will often establish a colony on, or nearby to their traditional site. We still don't fully understand all the reasons for their choice of camp-sites.  If we spared wildlife sites and green corridors as part of a planned approach to our overall city planning, we could avoid this conflict.

So what is the solution?
We have only just touched on the importance of bats as a species. Most of the conflicts between us and bats has been caused by our approach to urban and rural development, which has taken little or no account of the needs of native species.

We can either ignore the situation and let these valuable animals continue their plunge to extinction, or try to increase the amount of green space and wildlife corridors to accommodate bats and other native species.  If we do not take action, many of these species will be lost, and we do not fully understand the impact that will have on the environment - but it is unlikely to be good.

The best thing you can do is to take an interest, and see these animals for what they really are.  Help wildlife care groups who rescue bats, and if there is an issue in your local area, take a stand for the protection of these, and all of Australia's unique wildlife.

Page updated September 2010



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