rats queensland
© Supplied: Tia BooThousands of rats washed up on the Karumba foreshore.
The north Queensland town of Karumba is home to saltwater crocs, brolgas and black swans and, more recently, hundreds of swimming rats.

A sea of rodents has been washing up dead on the beach in recent days, with others scurrying across the boat ramps into garden sheds and homes.

Yvonne Tunney is one of about 500 residents who lives in the small coastal town. The Gulf suburb is a fisherman's paradise known for its barramundi spoils, prawning and crabbing but recently it has become more famous for its rodent problem.

"They get on the move in mass numbers ... A week ago the river was just alive with rats floating around," she told Guardian Australia.

"Everybody's working furiously with baits and traps to get them under control.

"Nature is working with us with the hawks and kites, they're very busy having a feast."

Tunney said "the sand island" that appears at low tide on the Karumba port had been blanketed in the native long-haired rats.

"We're very happy for them to be heading out that way to head out into the Gulf and disappear," she said.

Tina Hutchinson owns a fishing company in Karumba and says the last thing her business needs is rats in the river or scampering through her boats.

At her home in the town, the creatures have chewed through all of the irrigation in her garden.

"You can't keep your doors open because you'll have rats inside," she told Guardian Australia. "If you go out in your car at night, you can see them all just running around."

After a heavy wet season, the rat plague has affected a multitude of towns in outback Queensland including Richmond, Cloncurry and Julia Creek.

Prof Peter Banks, a rodent expert from the University of Sydney, said the long-haired rat is nicknamed "the plague rat" for obvious reasons.

"They call it the plague rat because they periodically undergo very big increases in abundance.

"They've got very high reproductive rates ... so when big rain falls in arid environments, which is their natural habitat, they increase."

There is an 80% chance of a plague after rainfall of 750ml, according to Banks. In arid areas, these sort of scenes only happen once a decade, he said.

"What we're seeing now is the natural result of too many rats - not enough food, not enough space - in the wrong place."

About 70km away from Karumba in Normanton, Derek Lord is battling an infestation of his own.

Lord runs a car hire business in town and says the rats have completely destroyed one of his vehicles by chewing the electrics out.

To deal with the swarm of vermin, Lord and his family have been tossing scraps in the bin and hoping they get trapped inside.
rats karumba
© Derek Lord
"I've found about 50 of them in the bin the past couple of days," he said. "They're everywhere ... I heard them behind the freezer the other night."

"If they keep destroying my cars, it's gonna cost me a fair bit to stay in business."

Jack Bawden, the mayor of Carpentaria shire council, said his community had been preparing for the rats to head north for some time.

"They've been in Richmond and ... they probably started turning up last week in numbers. And this week the numbers are getting thicker," he said.

"They just float ... up and down in the tide until eventually they disintegrate. It's not a very pretty sight."

Bawden said there was not much council could do other than set traps in wheelie bins.

"It's a quirk of nature ... I'll dare to say there's a lot of fat bull sharks and tiger sharks out in the Gulf [at the moment]," he said.

Mick Quirk, the manager of environment and sustainability policy at Canegrowers, said farmers always struggle to get rats under control but 2023 has been a particularly bad year.

In the Cairns area, another type of rat - climbing rats - have caused a headache for farmers, affecting about 5,000-10,000 hectares of crop.

"A couple of districts have had plague-like proportions in their paddocks. Much worse than normal," he said.

Banks said it was not common for these type of plagues to last as long as they have in north Queensland.

"Usually plagues happen in huge number and [rodents] move across the landscape looking to try and escape all the competition for food ... but this has been going on for months," he said.

"Plagues run out because the animals can't live that long without food.

"If they've stopped breeding, that's the first sign that the population is going to crash. Seeing a lot of dead animals is another sign."

This story was amended on 24 November, 2023 to correct the mention of hawks and kites feeding on the rats, after a transcription error originally suggested it was hawks and caiques.