A PhD student studying the environmental impact of animal carcasses has filmed a feral cat eating an entire kangaroo in the Simpson Desert.

Key points: The feral cat consumes a 30kg kangaroo over several days

The feral cat consumes a 30kg kangaroo over several days The discovery is unusual, with wedge-tailed eagles the main scavenger in the region

The discovery is unusual, with wedge-tailed eagles the main scavenger in the region Cats turning to scavenging is likely due to ongoing drought conditions reducing their food supply

Emma Spencer from the University of Sydney set up a number of surveillance cameras on a range of different carcasses including camels and kangaroos, on Bush Heritage Australia's Ethabuka Reserve, 640 kilometres south of Mount Isa.

Emma Spencer studies the environmental impact of dead animal carcasses. ( Supplied: Emma Spencer )

"We've had this one [cat] come in and pretty much take out an entire 30-kilogram kangaroo, eating it all over a number of days," Ms Spencer said.

"It was probably a very happy cat.

"He certainly benefited from that one carcass."

Ms Spencer said it was an anomaly in her research, which found wedge-tailed eagles were the main scavenger in the area.

"Cats up there, if they come across a carcass it's a free meal," she said.

"There might be very little competition for that carcass.

"They did come in [to] a few other carcasses but, in general, in environments like this, what you'll see is the birds coming in to break down the carcasses."

Drought forces cats to scavenge

University of Adelaide ecologist John Read said, despite being natural predators, prolonged drought conditions in South Australia and New South Wales had forced feral cats to scavenge.

"This drought is biting into their main food supply, which is rodents, small birds, and reptiles," Dr Read said.

"So the cats that are out there are turning to scavenging, which is not their normal behaviour."

Dr Read says a lack of prey from drought has forced feral cats to scavenge. ( ABC Rural: Brooke Neindorf )

Dr Read said he had done a similar study in SA about 15 years ago that showed very different results.

"That was an area with lots of feral cats and I didn't have a single feral cat approach them [the carcasses].

"Wedge-tailed eagles and crows and ravens were the main scavengers there.

"I assume this is an unusual response to the lack of alternate food."

Surprising lack of wild dogs

Despite wild dogs and dingos being a major predator in the area, Ms Spencer said they were rarely seen feeding off carcasses.

"Going out onto the site I had high expectations that we would get a lot of dingo activity," she said.

Surveillance suggests wedge-tailed eagles are the main Simpson Desert scavenger. ( Supplied: Emma Spencer )

"We did get them visiting quite a few carcasses, but in general we didn't actually see them feeding off the carcasses."

Ms Spencer said there was still a large number of kangaroos moving through the Simpson Desert, which potentially kept the wild dogs busy.

"It's very possible that they had alternative sources of food and they were simply going for the kangaroos and turning up their noses to the carcasses," she said.

"Maybe [the carcasses] were too smelly or maybe the [wild dogs] were just full of food."

Dr Read agreed wild dogs were likely to be scavenging in the area.

"There's probably plenty of food for those dogs and maybe they weren't coming to those few carcasses she had the cameras on," he said.

"That's their main food."