The feral cat: one newcomer that has the
advantage over many native species in the survival stakes
Photo: Greg Calvert
Getting the cat into the bag:
just what toll are feral cats exacting on wildlife?
As an adjunct to a survey of fauna in the
Desert Uplands, conducted by Dr Alex Kutt, the diets of feral cats
were examined via stomach contents, which were systematically
collected across the bioregion and the directly adjacent areas of
the Mitchell Grass Downs and Northern Brigalow Belt. Samples were
obtained by local professional kangaroo and pig shooters.
A total of 194 cat guts were collected over
two years comprising 1300 prey items. Initial sorting revealed some
broad patterns: of all prey items identified, 16 per cent were
birds, 33 per cent reptiles, 5 per cent amphibians, 25 per cent
mammals, and 21per cent insects.
And volume of prey was frightening: one cat
had consumed two birds, one dunnart, one dragon and seven geckoes
while another, one dunnart, three dragons, eight geckoes and one
tree skink. Multiplied over a year, this translates to a
The influence of feral cats on native fauna,
particularly in recently modified habitats, is not well understood,
and regional information is sorely needed. Hopefully this data will
contribute to the debate on the impact of feral cats, which
currently does not receive nearly enough attention.
from Savanna Links 19
Over the past 200 years, colonising peoples have brought to
Australia a huge number of animals—mainly mammals—that
did not evolve here. The results of these introductions have often
been dramatic, changing the natural environment irrevocably because
of the newcomers. Generally, animals (and plants) were brought here
for a reason—hence, we speak of deliberate
introductions—but often small numbers 'escaped' from human
control and started self-sustaining feral populations.
Other introductions have been accidental; stowaway rats or cats
jumping ship, for example, or small invertebrates arriving on
imported produce or attached to ocean-going liners.
Even the dingo, often seen as quintessentially Aussie, is very
closely related to the South-East Asian dog. Dingoes are in fact,
fairly new arrivals introduced by humans probably about 3 to 5000
Why ferals flourish
Whether accidental or deliberate, most animals introduced to
Australia by humans thrived, usually because here they have escaped
the predators and parasites that plague them in their areas of
origin. As well, there are often fewer competitors. And the
wide-open spaces with few large natural land barriers (except
deserts) also helps some species spread.
Examples of ferals
Many of the best-known examples of introduced animals and their
effects come from southern and central Australia. But the tropical
savannas of the north have also suffered. Tropical Australia is a
huge area of great conservation, agricultural and tourism
potential, but it is now home to the following 'alien' species:
- Asian water buffalo
- Cane toad
- Feral (unbranded) cattle
- Dingo/feral dog
Small populations also exist of:
- Banteng cattle (originally from Indonesia) on Cobourg Peninsula
Sambar deer ( Cervus unicolor ), an Asian deer, with a
population on Cobourg peninsula (but in Monsoon rainforest)
- Chital deer ( Cervus axis ) in parts of tropical western
- Rusa deer in some Torres Strait islands and North-East Island
(next to Groote Eylandt)
- In the more arid parts of the zone are camels, spreading from
their desert range.
- Feral goats occur in parts of Queensland's and Western
Wild pigs could be the biggest threat to natural
ecology in Australia's north
Photo: Jim Mitchell
Australia's biggest scourge, the rabbit, is rare in the
semi-arid tropics, but feral pigs are plentiful. Many experts see
wild pigs as the biggest threat to the natural ecology of the north
of the country.
Click on the sub-menu at left to find out more about selected
individual feral animals.
Impact of feral animals
Little research has taken place on the long-term impacts of
ferals grazing in the savannas. Scientists have ideas of the likely
effects, but little hard data that applies to large areas over many
years. For example, experience in semi-arid areas of Africa
suggests that camels can have a large effect on the land but the
situation in equivalent parts of Australia has simply not been
studied in sufficient detail.
The same holds true for feral pigs and the widely distributed
feral cat. What effects, if any, these animals are having on native
ecosystems are largely unquantified.
What we do know is that in some places, at certain times, some
feral species can cause undesirable changes to native ecosystems,
threaten the survival of other species, and become a serious
nuisance and cost to farmers. But changes caused by ferals may be
occurring slowly and insidiously without us being fully aware of
the situation until it is too late.
In many parts of Australia dingoes have cross-bred with other
dog types that have escaped domestication. Dingoes/feral dogs are a
nuisance to pastoralists because they prey on lambs and calves and,
when hunting in packs, will even harass fully grown adults. It is
considered quite possible that dingoes caused thylacines to become
extinct on the Australian mainland over the last few thousand
years. But dingoes are now part of the accepted Australian fauna.
Indeed, they may even help in the battle against newer ferals, for
example, by keeping down fox numbers in temperate areas.
For most feral species, the future may be something similar to
the dingo story—adaptation both by the species and by the
rest of Australia to it, along with targeted damage control, rather
Management of feral animal populations and any associated
problems is very difficult in the vast and sparsely populated areas
of northern Australia. For a start, there is little information on
the extent and size of feral populations and on the effects they
may be causing.
It is not known whether impacts are always proportional to the
density of the feral population. This is a key question when it
comes to control. It is surely better to respond to measurable or
observable impacts rather than the absolute density of a
There is also the problem of conflicting interests.
Agriculturalists, traditional owners, tourism operators and
conservationists all have different agendas. Whose viewpoint will
be given priority? Control options are likely to be expensive and
so can often only be justified if the target animal is causing
clear economic loss. This monetary emphasis can mean that damage to
unique but non-economic ecosystems may go unchecked.
Department of the Environment, Water, Heritage and the Arts - Feral Animals
An introduction to feral animals in Australia, control methods and Australian Government action.
Factsheets Resource Net: Queensland Department of Environment and Resource Management
National Feral Animal Control Progam
The National Feral Animal Control Program (NFACP) ran from 1996-2008 under the Natural Heritage Trust. NFACP has been replaced by the Australian Pest Animal Management Program (APAMP), funded under the Caring for our Country initiative. The focus of APAMP is similar to that of NFACP - that is, research to promote strategic, sustained best practice management of pest animals where they are causing actual rather than perceived damage. The below link provides examples of previous projects funded under NFACP.