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
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
 Most
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.
-
Bats
carry deadly viruses
 A
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.
-
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.
-
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 |
