The Kapalga Cat Experiment

Kapalga Cat Experiment banner

Understanding the role of feral cats in the northern mammal decline


Australia has the world’s worst record of mammal extinctions. In the last 200 years half of the world’s mammal extinctions have occurred here. About 10% of our native mammal species have been lost forever.

While most of these extinctions occurred in southern and central Australia in the 20th Century, we are now witnessing a second wave of mammals declines in northern Australia’s vast uncleared landscapes. Over the last few decades, mammals have disappeared from many northern Australian landscapes, including conservation reserves such as Kakadu National Park where once-common mammal species are now virtually absent. Urgent management action is required if we are to prevent further mammal extinctions.

Alarmingly, conservation scientists still don’t understand the cause of the northern mammal declines, but there is an emerging theory that feral cats – which are highly efficient predators of small mammals – are to blame. But this is still just a theory, and we lack solid evidence upon which to develop strategies for land management agencies to effectively manage mammal populations.

Study design


Kapalga fence 7Jun18Our project will focus on two large cat exclusion fences (64 ha each) at Kapalga in Kakadu National Park, Northern Territory. They were built in 2013, as part of a research project run by the park and the Northern Territory Government; that project ended in 2017. Fortunately, the cat exclosures remain intact, with no cats inside.

We will re-introduce four mammal species to the cat-free areas: northern brown bandicoot; northern brushtail possum; black-footed tree-rat; northern quoll. These species have declined dramatically across northern Australia, most likely due to cats.

We will closely monitor the re-introduced mammal populations over 5 years. Three of the study species can climb fences, and will potentially leave the cat-free areas, so we will monitor the fate of individuals leaving the exclosures (via GPS tracking collars).

20170905_065435Should these species flourish in the absence of cats, it will provide compelling evidence that cats are a key driver of mammal decline in Kakadu and elsewhere in northern Australia. We will evaluate whether providing a cat-free source population enables native mammals to recolonise and survive in surrounding areas despite the presence of cats.



Student projects

If you are a prospective student (PhD, Master’s, Honours) and are interested in a project which makes use of the Kapalga experiment, please get in touch.


Dr Brett Murphy
Research Institute for the Environment and Livelihoods
Charles Darwin University, Darwin NT 0909, Australia

Phone: +61 (0) 8 8946 6049
Mobile: +61 (0) 466 623 079

Dr Teigan Cremona
Research Institute for the Environment and Livelihoods
Charles Darwin University, Darwin NT 0909, Australia

Phone: +61 (0) 8 8946 7728