They're big, strong and, if you've heard the popular adage, smarter than your dog. Now experts are saying illegal hunters are spreading feral pigs even further for sport.

Landcare biosecurity officer Annabelle Garrett, described the non-fussy omnivores, that hunt livestock and native animals, eat crops, down fences and spread serious disease, as the "perfect pest".

After plaguing farmers in the south-west corner of Western Australia for decades, late last year an environmental management group further inland in the state's grain belt received a spate of reports of feral pig sightings.

Now whole families of swine have been reported for the first time in the Great Southern shire of Wagin.

"The last but maybe most concerning [factor] is illegal dumping and breeding of pigs … we're seeing a lot of that happen around the state now," Ms Garrett said.

"People are actually breeding and transferring pigs for recreational hunting."

A feral pig is caught on a surveillance video in the South West of WA. ( Supplied )

This little piggy went everywhere

Feral pigs of the species Sus scrofa are one of the most successful land mammals in the modern world, spread by humans to every continent except for Antarctica.

Long before 'pig' became a pejorative term, boars were famed by hunters for their sheer size, strength and ferocity and appeared in heraldry and literature.

In Homer's The Odyssey, the poem's titular returning warrior carries a scar from when he was gored by a mighty boar in his first of many great battles. The Ancient Romans embraced hunting with vigour and spread pork production throughout their empire.

When Commodore Arthur Phillip arrived with the First Fleet in Botany Bay, 49 hogs were brought ashore to feed the newly established colony.

Australia is now home to around 25 million feral pigs.

"They were farmed or managed in a sort of semi-feral state [and] free-range populations would have been kicked off from there," said Dr Peter Adams, who has been researching feral pigs at Murdoch University and the WA Department of Agriculture for almost 20 years.

"Feral pigs are very fecund when it comes to reproductive capacity, sows are capable of having two litters a year, provided that the resources, food and shelter are available. Sows are breeding at six months of age and their litter sizes are on average around about six piglets per litter.

"It doesn't take much for one or two pigs to become a very large problem."

In the past pig seeding has been dismissed by some as urban legend, but in 2015 scientists at Murdoch University in Perth used DNA to prove that pigs had been illegally introduced into new areas in Western Australia.

Using the same technology, scientists in the United States have tracked the destructive spread of wild hogs by hunters across the country.

Dr Adams said it was not a matter of "if" pigs were being dumped, it was a matter of when, where and how many.

"Unfortunately we also do have the added issue where some people who enjoy hunting pigs … do like to actually spread pigs around for we presume continued hunting enjoyment or moving pigs to areas where it's not so far to travel to be able to hunt them," he said.

"The illegal seeding or translocation or dumping, there are many different terms for it … of feral pigs is a practice that does occur not just in the South West but in association with feral pig populations [everywhere].

Scientists use DNA technology to trace animals that had been moved from different regions. ( Supplied: Murdoch University )

"Pigs are quite capable of moving reasonable distances on their own and when humans get involved and start moving them as well it doesn't help the situation."

New South Wales and Queensland have a long fought battle with feral pigs, but Dr Adams said reports of feral pigs moving into Western Australia sheep and grain heartlands was cause for concern.

"I've spoken with farmers who have experienced significant sorts of impacts due to pigs, whether it's damage to pasture and loss of grazing land for livestock," he said.

"In some extreme cases entire paddocks of crop have been lost to damage directly due to pigs."

Farmers scared to speak

Aside from putting huge pressure on Australia's native animals and fragile ecosystems, Australian farmers lose more than $100 million to feral pigs each year.

Many are reluctant to go on the record about the topic for fear of backlash or attracting illegal hunters who trespass on their properties.

'Dave' is a sheep farmer who used to run a block in Collie in WA's south-west. He said the loss of around 700 lambs one year to a rogue pack of pigs was a contributing factor in his decision to sell the block.

"The pigs actually ate the lambs as they were being born," he said.

"I had absolutely no idea they were capable of that."

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The farmer now ran sheep in one of the areas in the Great Southern that was experiencing an increase in pig sightings.

"Someone let some pigs go closer to home, so they are appearing around the place," he said.

"It was a pretty big effort to get rid of the half a dozen someone dropped up that way."

When asked about those releasing the animals, he said it was probably a small group of people unaware of what they were doing.

"It's a game I think. They probably don't realise the impact it has on the environment and farmers," he said.

"Confronting people these days is a pretty risky thing sometimes. I'd certainly take details of the vehicles and get the constabulary to have a word with them."

A farm hand in the Great Southern witnessed this boar, estimated to be over 100kg, hunt down and kill seven fully grown sheep. ( Supplied )

Legitimate hunters part of solution

Sporting Shooters Association of Australia WA president Ron Bryant said he did not consider the culprits accused of moving pigs around the state to be worthy of the title bestowed on them.

"I wouldn't even call them hunters … there are other words I'd use for them that you could probably pick up," he said.

"Whether it's true or not, if it is a practice I find it deplorable."

Mr Bryant, who has been shooting for more than three decades, said legitimate hunters worked with farmers, not against them by trespassing on properties or releasing a declared pest, which carries a fine of $50,000 under the state's Biosecurity and Agriculture Management Act 2007.

"There may be one or two but I'd say generally now because pretty much by and large all our people are ticking every box they can think of to do the right thing," he said.

"They're not going to be … doing an activity that's going to lose them integrity and their [gun] licence ultimately."

"If someone was to get caught they do get the book thrown them in a massive way."

The association sponsors the state's Red Card for Rabbits and Foxes program, which helps farmers deal with damaging invasive pest species including pigs.

Dr Adams said coordinated community approaches, such as the Red Card program, was the most effective solution for the problem.

"The time for pig management is now the longer you wait the harder the problem is going to be," he said.

"These animals are highly mobile, they can move across land boundaries very quickly and very easily they don't pay attention or respect fences or boundaries — they go where they want.

"That coordinated control is going to give you your best option to put the brakes on that population as soon as possible."