Wild ‘super pigs’ from Canada could become a new front in the war on feral hogs

"EVIL COMES FROM THE NORTH"

LOG LADY, TWIN PEAKS

The Conversation
December 22, 2023

Feral hogs’ long snouts and tusks allow them to rip and root their way across the landscape in search of food. 

USDA/Flickr, CC BY

They go by many names – pigs, hogs, swine, razorbacks – but whatever you call them, wild pigs (Sus scrofa) are one of the most damaging invasive species in North America. They cause millions of dollars in crop damage yearly and harbor dozens of pathogens that threaten humans and pets, as well as meat production systems.

Although wild pigs have been present in North America for centuries, their populations have rapidly expanded over the past several decades. Recent studies estimate that since the 1980s the wild pig population in the United States has nearly tripled and expanded from 18 to 35 states. More recently, they have spread rapidly across Canada, and these populations are threatening to invade the U.S. from the north.

The wild pigs in Canada are unique because they were originally crossbred by humans to be larger and more cold-hardy than their feral cousins to the south. This suite of traits has earned them the name “super pigs” for good reason. Adults can reach weights exceeding 500 pounds, which is twice the size of the largest wild pigs sampled across many U.S. sites in a 2022 study.

As a wildlife ecologist, I study how wild pigs alter their surroundings and affect other wildlife species. Early detection and rapid response is of utmost importance in eradicating an invasive species, because invasions are more manageable when populations are small and geographically restricted. This is especially true for species like wild pigs that have a high reproductive rate, can readily move into new areas and can change their behavior to avoid being captured or killed.

Minnesota wildlife experts are keeping a wary eye on their northern border for signs of wild ‘super pigs’ moving down from Canada.

Omnivores on the hoof

Much concern over the spread of wild pigs has focused on economic damage, which was recently estimated at about US$2.5 billion annually in the United States.

Wild pigs have a unique collection of traits that make them problematic to humans. When we told one private landowner about the results from our studies, he responded: “That makes sense. Pigs eat all the stuff the other wildlife do – they just eat it first, and then they go ahead and eat the wildlife, too. They pretty much eat anything with a calorie in it.”

More scientifically, wild pigs are called extreme generalist foragers, which means they can survive on many different foods. A global review of their dietary habits found that plants represent 90% of their diet – primarily agricultural crops, plus the fruits, seeds, leaves, stems and roots of wild plants.


Lesser prairie chickens are a ground-nesting species – found in parts of Colorado, Kansas, New Mexico, Oklahoma and Texas – that is listed under the Endangered Species Act. Feral hogs prey on the birds and their eggs and damage the birds’ habitat by rooting up and consuming native plants and spreading invasive plant seeds. Greg Kramos/USFWS

Wild pigs also eat most small animals, along with fungi and invertebrates such as insect larvae, clams and mussels, particularly in places where pigs are not native. For example, a 2019 study reported that wild pigs were digging up eggs laid by endangered loggerhead sea turtles on an island off the coast of South Carolina, reducing the turtles’ nesting success to zero in some years.

And these pigs do “just eat it first.” They compete for resources that other wildlife need, which can have negative effects on other species.

However, they likely do their most severe damage through predation. Wild pigs kill and eat rodents, deer, birds, snakes, frogs, lizards and salamanders. This probably best explains why colleagues and I found in one study that forest patches with wild pigs had 26% fewer mammal and bird species than similar forest patches without pigs.

This decrease in diversity was similar to that found with other invasive predators. And our findings are consistent with a global analysis showing that invasive mammalian predators that have no natural predators themselves – especially generalist foragers like wild pigs – cause by far the most extinctions.

Altering ecosystems

Many questions about wild pigs’ ecological impacts have yet to be answered. For example, they may harm other wild species indirectly, rather than eating them or depleting their food supply.

Our work shows that wild pigs can alter the behavior of common native wildlife species, such as raccoons, squirrels and deer. Using trail cameras, we found that when wild pigs were present, other animals altered their activity patterns in various ways to avoid them. Such shifts may have additional cascading effects on ecosystems, because they change how and when species interact in the food web.


Another major concern is wild pigs’ potential to spread disease. They carry numerous pathogens, including brucellosis and tuberculosis. However, little ecological research has been done on this issue, and scientists have not yet demonstrated that an increasing abundance of wild pigs reduces the abundance of native wildlife via disease transmission.

Feral hogs can be seen rooting up the soil in this trail camera footage from Alabama.

Interestingly, in their native range in Europe and Asia, pigs do not cause as much ecological damage. In fact, some studies indicate that they may modify habitat in important ways for species that have evolved with them, such as frogs and salamanders.

So far, however, there is virtually no scientific evidence that feral pigs provide any benefits in North America. One review of wild pig impacts discussed the potential for private landowners plagued with pigs to generate revenue from selling pig meat or opportunities to hunt them. And it’s possible that wild pigs could serve as an alternative food source for imperiled large predators, or that their wallowing and foraging behavior in some cases could mimic that of locally eradicated or extinct species.

But the scientific consensus today is that in North America, wild pigs are a growing threat to both ecosystems and the economy. It is unclear how invading super pigs would contribute to the overall threat, but bigger pigs likely cause more damage and are generally better predators and competitors.

While efforts to control wild pigs are well underway in the U.S., incursions by Canadian super pigs may complicate the job. Invasive super pigs make for catchy headlines, but their potential effects are no joke.

This is an updated version of an article originally published on Aug. 26, 2019.

Marcus Lashley, Associate Professor of Wildlife Ecology, University of Florida


This article is republished from The Conversation under a Creative Commons license. Read the original article.

CANADIAN, EH

‘Incredibly intelligent, highly elusive’: US faces new threat from Canadian ‘super pig’
'EVIL COMES FROM THE NORTH ' - TWIN PEAKS
Adam Gabbatt
Mon, February 20, 2023 

Photograph: David Carson/AP

For decades, wild pigs have been antagonizing flora and fauna in the US: gobbling up crops, spreading disease and even killing deer and elk.

Now, as fears over the potential of the pig impact in the US grow, North America is also facing a new swine-related threat, as a Canadian “super pig”, a giant, “incredibly intelligent, highly elusive” beast capable of surviving cold climates by tunneling under snow, is poised to infiltrate the north of the country.

Related: Lynx facing extinction in France as population drops at most to 150 cats

The emergence of the so-called super pig, a result of cross-breeding domestic pigs with wild boars, only adds to the problems the US faces from the swine invasion.

Pigs are not native to the US, but have wrought havoc in recent decades: the government estimates the country’s approximately 6 million wild, or feral, pigs cause $1.5bn of damage each year.

In parts of the country, the pigs’ prevalence has sparked a whole hog hunting industry, where people pay thousands of dollars to mow down boar and sow with machine guns. But overall, the impact of the pigs, first introduced to the US in the 16th century, has very much been a negative, as the undiscerning swine has chomped its way across the country.

“We see direct competition for our native species for food,” said Michael Marlow, assistant program manager for the Department of Agriculture’s national feral swine damage management program.

“However, pigs are also accomplished predators. They’ll opportunistically come upon a hidden animal, and the males have long tusks, so they’re very capable of running and grabbing one with their mouth.

“They’ll kill young fawns, they’re known to be nest predators, so they impact turkeys and potentially quail.”

The wild pigs are also responsible for a laundry list of environmental damages, ranging from eating innocent farmers’ crops to destroying trees and polluting water. They also pose “a human health and safety risk”, Marlow said.

A pig is a “mixing vessel”, capable of carrying viruses, such as flu, which are transmittable to humans. National Geographic reported that pigs have the potential to “create a novel influenza virus”, which could spread to humankind.

The first record of pigs in the continental US was in 1539, when the Spanish explorer Hernando De Soto landed in Florida with an entourage which included 13 swine.

During the four-year expedition, which saw De Soto order the slaughter of thousands of Native Americans, declare himself “an immortal ‘Son of the Sun’”, and then die of a fever, the number of pigs grew to about 700, spread across what is now the south-eastern US.

But it is only relatively recently that the pigs have become a problem.

“They lived a benign existence up until, you know, probably three or four decades ago, where we started seeing these rapid excursions in areas we hadn’t seen before,” Marlow said.

“Primarily that was the cause of intentional releases of swine by people who wanted to develop hunting populations. They were drugged and moved around, not always legally, and dropped in areas to allow the populations to develop. And so that’s where we saw this rapid increase.”

The number of pigs in the US has since grown to more than 6 million, in some 34 states. The pigs weigh between 75 and 250lbs on average, but can weigh in twice as large as that, according to the USDA. At 3ft tall and 5ft long, they are a considerable foe.

Marlow said his team had managed to eradicate pigs in seven states over the past decade, but with little realistic hope of getting rid of the swine completely, there are also fears over the potential impact of pig-borne disease, particularly African swine fever.

The disease is always fatal to pigs, and in China, which is home to more than 400 million pigs – half of the world’s pig population – African swine fever wiped out more than 30% of the pig population in 2018 and 2019. African swine fever has presented in Europe, too, but Marlow said it has not yet been detected in the Americas.

That’s something that Ryan Brook, who leads the University of Saskatchewan’s Canadian wild pig research project, hopes to maintain.

In Canada, like in the US, wild pigs are a relatively recent problem. Up until 2002 there were barely any wild pigs in the country, but Brook said the population has exploded in the past eight years. The animals are now spread across 1m sq km of Canada, predominantly in Alberta, Manitoba and Saskatchewan.

“Wild pigs are easily the worst invasive large mammal on the planet,” said Ryan Brook.

“They’re incredibly intelligent. They’re highly elusive, and also when there’s any pressure on them, especially if people start hunting them, they become almost completely nocturnal, and they become very elusive – hiding in heavy forest cover, and they disappear into wetlands and they can be very hard to locate.”

Brook and others are particularly troubled by the emergence of a “super pig”, created by farmers cross-breeding wild boar and domestic pigs in the 1980s. The result was a larger swine, which produced more meat, and was easier for people to shoot in Canadian hunting reserves.

These pigs escaped captivity and swiftly spread across Canada, with the super pig proving to be an incredibly proficient breeder, Brook said, while its giant size – one pig has been clocked at more than 300kg (661lbs) – makes it able to survive the frigid western Canada winters, where the wind chill can be -50C.

“All the experts said at that time: ‘Well, no worries. If a wild pig or a wild boar ever escaped from a farm, there’s no way it would survive a western Canadian winter. It would just freeze to death.’

“Well, it turns out that being big is a huge advantage to surviving in the cold.”

The pigs survive extreme weather by tunneling up to 2 meters under snow, Brook said, creating a snow cave.

“They’ll use their razor-sharp tusks to cut down cattails [a native plant], and line the bottom of the cave with cattails as a nice warm insulating layer.

“And in fact, they’re so warm inside that one of the ways we use to find these pigs is to fly first thing in the morning when it’s really cold, colder than -30, and you will actually see steam just pouring out the top of the snow.”

Given the damage the pigs have wrought, a range of attempts have been made to get rid of them. Scientists and researchers in the US and Canada have had some success with catching whole sounders of pigs in big traps, while in the US attempts have been made – sometimes unsuccessfully – at poisoning wild pigs.

One method that has worked in the US, Brook said, is the use of a “Judas pig”. A lone pig is captured and fitted with a GPS collar, then released into the wild, where hopefully it will join a group of unsuspecting swine.

“The idea is that you go and find that collared animal, remove any pigs that are with it, and in ideal world then let it go again and it will just continue to find more and more pigs,” Brook said.

Brook said a variety of methods are required to tackle the pig problem. But the efforts are more about managing the damage caused by these non-native mammals, rather than getting rid of the pigs completely. In Canada, that chance has gone.

“Probably as late as maybe 2010 to 2012, there was probably a reasonable chance of finding and removing them. But now, they’re so widespread, and so abundant, that certainly as late as 2018 or 19 I stopped saying that eradication was possible. They’re just so established,” Brook said.

“They’ve definitely moved in, and they’re here to stay.”

Piggy in the middle: Pig aggression reduced when a bystander pig steps in

Peer-Reviewed Publication

SPRINGER

A small study suggests that when two pigs are fighting, a bystander pig can intervene to either reduce the number of attacks by the aggressor or to help reduce the anxiety of the victim. The study of 104 domestic pigs, published in the journal Animal Cognition, reveals the complex social groups that pigs form and how they may resolve conflict.

In social animals, conflict resolution involves either the reunion of former opponents — an aggressor and victim — after an aggressive event (known as reconciliation), or the introduction of a third-party bystander to reduce further aggression or anxiety (known as triadic contacts). These conflict-resolution strategies are important to maintain balance in social animal groups and reduce victim anxiety, but it is unclear how this applies to domestic pigs.

Giada Cordoni, Ivan Norscia and colleagues from the University of Torino (Turin, Italy) observed how a group of 104 pigs housed at the ethical farm Parva Domus (Turin, Italy) resolves conflict after fighting. The authors could identify most generations of pigs based on their breed, size and markings but also genetically tested 31 pigs across different generations to determine relatedness across the whole group. They observed and recorded interactions between the pigs from June to November 2018 and noted aggressive behaviours such as head-knocking, pushing, biting and lifting of the victim pig. The authors watched behaviour for three minutes after each aggressive conflict and noted gender, kinship, and age.

The authors observed that both the aggressor and victim showed reconciliation behaviour such as nose-to-nose contact, sitting in physical contact with one another and resting their head on the other. They found that both the aggressor and the victim initiated reconciliation behaviours equally after fighting. However, they found that the proportion of reconciliations was significantly higher in more distantly related pigs compared to closely related pigs.

The authors propose that pigs may value different relationships based on what they can provide, such as social support. The damage to social groups caused by fighting closely-related kin (half or full siblings) may be less because these could be considered as more secure relationships. However, distantly related pigs may be more likely to engage in reconciliation behaviour after fighting to ensure they still have social support and access to food within the group.

When observing conflict resolution involving a third party pig, the authors noted behavioural differences depending on who the bystander pig approached and engaged with after the fight. If the bystander approached and engaged with the victim, the number of aggressive behaviours did not change, but the mean hourly frequency of anxiety-related behaviours observed in the victim was significantly lowered. Anxiety-related behaviours included shaking, scratching, chewing with an empty mouth and yawning. However, if a bystander pig approached the aggressor, the number of aggressive behaviour attacks directed towards the victim was significantly reduced.

A higher proportion of bystander pigs intervened if the conflict involved either an aggressor or victim they were closely related to. The authors suggest this indicates that pigs value certain relationships and may support closely-related kin.

The victim pig attempting to approach and engage with a bystander after conflict had no effect on reducing post-conflict anxiety behaviour or the likelihood of being attacked again. This may be due to 95.2% (42 cases) of the bystander pigs not reciprocating the union when a victim approached them.

The authors caution that this study involves only one group of adult, domestic pigs, and therefore may not represent all pig groups. Future research could investigate if these conflict-resolution strategies are seen in other situations.

Pigs were found to engage in reconciliation and triadic contacts after conflict, which suggests pigs might possess some socio-emotional regulation abilities to change their own or others’ experience in group conflict, according to the authors.

###

Media Contact:

Tara Eadie
Press Officer
Springer Nature
T: +44 20 3426 3329 
E: tara.eadie@springernature.com

Notes to editor:

Domestic pigs (Sus scrofa) engage in non‑random post‑conflict affiliation with third parties: cognitive and functional implications

Animal Cognition 2022

DOI: 10.1007/s10071-022-01688-4

For an embargoed copy of the research article, related images and video please contact Tara Eadie at Springer Nature.

1. After the embargo ends, the full paper will be available at: https://link.springer.com/article/10.1007/s10071-022-01688-4

2. Please name the journal in any story you write. If you are writing for the web, please link to the article.

Animal Cognition is an interdisciplinary journal publishing current research from various backgrounds and disciplines (ethology, behavioral ecology, animal behaviour and learning, cognitive sciences, comparative psychology and evolutionary psychology) on all aspects of animal (and human) cognition in an evolutionary framework.

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JOURNAL

Animal Cognition

DOI

10.1007/s10071-022-01688-4 

Huge feral hogs invading Canada, building ‘pigloos’ as they go
Andrea Anderson NATIONAL GEOGRAPHIC 3/4/2020

© Photograph by Roland Seitre, Minden Pictures
Feral pigs are spreading through Canada. Here is a large 

boar in a park in Quebec, though the largest populations

 are found further west.
In the late 1980s and early 1990s, some Canadian farmers imported wild boars from Europe to raise for meat. But as wild boars are wont to do, some of them escaped, either digging under fences or barreling through them. Others were set free once the boar meat market cooled.

At first, it didn’t seem like a big problem; many thought they couldn’t survive Canada’s long winters. But the boars proved hardier than some researchers expected, and now they’re causing havoc across wide swaths of Canada.

The descendants of these wild boars have interbred with domestic pigs to varying degrees, and are now found throughout western and central Canada, from British Columbia to Manitoba and beyond. As they spread, they sow environmental destruction, plowing through crops and grasslands, causing erosion, displacing wildlife, harassing livestock, and eating just about anything.© Photograph by Neil Bowman, Minden Pictures

Feral pigs are better known in warm places like Florida, shown here. But they have shown the ability to survive in Canada's cold climate as well.

These feral fugitives can weigh up to 600 pounds or more, and sport sharp tusks and bristly coats over thick, warm fur. They are reproducing rapidly and their range is expanding. Their combination of wild traits and domestic ones—including their high tolerance for cold and ability to birth large litters—may have led to “super pigs,” says Ryan Brook, a wildlife researcher with the University of Saskatchewan. The creatures even have been known to build above-ground shelters that researchers have dubbed “pigloos.”

© Photograph by Ryan Brook
Feral hogs cut down cattails with their sharp teeth and use 

them to line the insides of their pigloos, or to make beds 

in which to rest in the summer.

“We should be worried, because we know the biology,” Brook says. “They're called an ecological train wreck for a reason.”

Got pigs?

The hog explosion is a new problem, and until recently, “no one even knew where they were,” says Ruth Aschim, a doctoral candidate at the University of Saskatchewan. She and her advisor Brook spent three years mapping their distribution using trail camera images, GPS collar data, and interviews with local landowners, farmers, and hunters.

For three months of the project, Aschim lived out of her tent and her car, meeting with local biologists and conservation officers across western Canada.

The results, published in a paper in Scientific Reports in May 2019

Porcine pests

Canadian feral hogs often eat crops such as wheat, barley, and canola as they range through prairies and farm lands and into the edges of forests and wetlands. They will make a meal out of most anything that fits into their mouths, including plants, small reptiles or mammals, ground-nesting birds, and eggs.

Beyond the damage they can do to field crops, grain bins and storage containers, the pigs can plow through large patches of farmland in search of invertebrates, roots, and other edibles.

“The rooting is really something to see. It's almost like a small backhoe has gone through some of these pastures,” says Perry Abramenko, an inspector and pest program specialist with Alberta Agriculture and Forestry.

Wild pigs also wallow in stream beds, causing erosion and water contamination, Abramenko says. And given their close relationship to domestic pigs, experts have raised concerns about potential infectious diseases that could be passed back and forth between the animals.

Canada’s pig problem is relatively new, however, and many impacts have yet to be fully felt. Crop insurance claims attributed to wild pigs in Saskatchewan, for example, are still far outpaced by damage from other wildlife, according to the Saskatchewan Crop Insurance Corporation.
Moreover, pigs are elusive; even though seen on trail cameras, residents might not know they’re around. Even so, economic and ecological problems associated with pigs—including risks posed to motorists—are expected to grow alongside the mushrooming pig population.

That has people like Brook concerned about the lack of a comprehensive plan to reduce their numbers in Canada, despite some initial efforts and meetings—lots of meetings. Without concrete action, time may be running out to turn back the wild pig tide.

“Meetings don't eradicate wild pigs,” he says.

Prior to such research, a Canadian feral pig scourge was hard to fathom. In the United States, the animals are best known in the south and warmer coastal areas, such as Florida, Texas, and California, where Spanish explorers introduced pigs as far back as the 1500s.

In western Canada, though, “we have the exact opposite,” Brook says. “The coldest spots—Manitoba, Saskatchewan, and Alberta, sort of north-central—is where we have, by far, the most pigs."

Why? The answer may lay partly in their history and heritage.

Swine on the move

Most taxonomists agree that domestic pigs and European wild boars are the same species, Sus scrofa, though different subspecies. They readily interbreed if given the chance. Wild boars are native to Eurasia, ranging from North Africa to Scandinavia and east to Siberia. They are not native to the Americas, though pig-like peccaries range throughout Latin America.

Humans have been raising domestic pigs, descendants of European wild boars, for around 10,000 years. The domestic variety has less hair and has been bred to be large and meaty, while reproducing quickly, particularly since the advent of commercial pig farming.

The descendants of escaped pigs can take on characteristics of their boar ancestors, including longer coats, though these “feral pigs” or “wild hogs” may harbor distinct color patterns and other remnants of domesticity.

Many feral pigs in the U.S. have strong domestic ancestry. A February 2020 study in Molecular Ecology of genetic data taken from 6,500 feral animals across the U.S. found that most descend from a mix of heritage breed domestic pigs—the kind raised as livestock prior to industrialized agriculture—and wild boar.
Their Canadian counterparts, however, are believed to be much more closely related to wild boars, but do have dashes of domestic pig ancestry. This is backed up by camera trap observations of hogs with pink coloration and polka-dot splotches, traits not seen in European wild pigs. They also have up to six piglets at a time twice per year, a larger litter size than that of Eurasian boars.

“If we had true Eurasian wild boar without any domestic pig, this whole issue would be a lot easier to handle… Reproductive rates would be lower,” Brook says.

The distinctive “pigloos” the animals build consist of mounds of cattails, which they cut down and burrow into, capturing enough heat to steam on cold days, Brook explains.

“The cattails do a good job of catching the snow and it's fairly thick and soft, so they can tunnel into that and have their little pigloos,” Brook says.
Why so big?

The animals are also notable for their smarts, toughness, and tremendous size.

While Eurasian wild boars tend to be smaller in the southern parts of their native range, they become bigger in the north, following a pattern common across many animal species. (Related: Wild boars make a home in bustling Hong Kong.)

A wild boar in Barcelona, for example, might be lucky to reach 220 pounds. That’s similar to North American wild pigs, which on average weigh between 150 and 220 pounds. Though Canadian pigs vary widely, Brook and his team captured at least one wild hog that was well over 600 pounds.

That apparent size increase may offer a selective advantage in the cold, Brook notes. Mixing between wild boar and commercial pig breeds likely contributes to that, since traits such as heft and large litter size have been under intense selection in farmed pigs as well.

These hybrid pigs and new and unfamiliar to many; it’s perhaps no wonder, then, that some folks don’t seem to think they present much of a threat, Brook says. But he disagrees. Pretty much everywhere else the pigs are found, they’ve created problems.

“Why would we expect anything except vast, dramatic ecological impacts?”

 

Large-scale mapping of pig genes could pave the way for new human medicines

Researchers from Aarhus University have carried out complex genetic analyses of hundreds of pigs and humans to identify differences and similarities.

Peer-Reviewed Publication

AARHUS UNIVERSITY

 

IMAGE: 

PIGS AND HUMANS ARE VERY SIMILAR. HUMAN AND PIG ORGANS ARE ALMOST THE SAME SIZE, AND MANY TISSUE TYPES ARE ALMOST IDENTICAL. THIS IS WHY PIGS ARE USEFUL WHEN DEVELOPING AND TESTING NEW DRUGS. THANKS TO THE NEW FINDINGS, WE KNOW HAVE EVEN BETTER KNOWLEDGE ABOUT THE SIMILARITIES BETWEEN PIGS AND HUMANS. 

view more 

CREDIT: JESPER RAIS, AU COMMUNICATION.

It may sound strange, but we can actually learn more about ourselves by studying pigs.

Pigs and humans are pretty similar. Our organs, our skin and the way many diseases develop are largely the same.

Pigs have therefore long been used to develop and test new medicines, even though pigs are larger, more expensive and more difficult to use in experiments than rats and mice.

And now pigs may become even more valuable as laboratory animals, because researchers from the Center for Quantitative Genetics and Genomics at Aarhus University have mapped the most important genetic similarities between pigs and humans.

The researchers have not only identified the genes that are the same in humans and pigs; they have also identified the so-called 'transcriptome' across a number of tissue types. Where the genome includes all the genes found in the DNA of our cells, whether active or inactive, the transcriptome includes the genes that are active in the different types of cells in our body, says Lingzhao Fang, one of the main researchers behind the new findings.

- We examined which genes are active and how they are regulated in 34 different types of tissue in pigs, and compared this with similar studies in humans. We looked at everything from testicular tissue to skin cells and various brain cells, he says and continues:

- No one has ever conducted a study at this scale and comprehensiveness, and we hope the new knowledge can make a difference in agriculture as well as in the pharmaceutical industry.

More useful knowledge from RNA

A little more than 20 years ago, a group of more than 1,000 researchers succeeded in mapping the entire human genome. After completing the project, the researchers hoped they could now develop treatments for nearly all diseases, because they now knew the code and could identify the errors.

But that is not how the story went.

The researchers soon discovered that there is a big difference between the genes in an individual’s recipe book and the recipes that are actually used and translated in the various cell types. 

This is what is also referred to as genotype and phenotype, with phenotype referring to the traits or symptoms that can be observed in an individual. Because of the greater role played by the transcriptome, a person can have the genetic disposition for a disease without actually suffering from the disease.

In other words, two people who, on paper, have the same disease mutation do not necessarily become ill to the same extent. With greater knowledge about the role of the transcriptome in various diseases, it is possible to develop better and more targeted medicines. 

And this is one area in which the results from Lingzhao Fang’s study can be useful when it comes to pigs as laboratory animals.

- Pigs become more suited as animals for testing new medicines. As the various tissue types in pigs and humans are very similar, in fact more similar than we thought, the pharmaceutical industry can test the safety of new medicines in pigs with much higher accuracy, he says. 

DNA, RNA and transcriptomes

In the centre of every human and pig cell, inside a small nucleus, are the long, two-stranded DNA molecules that make up the chromosomes. The strands consist of almost endless rows of four small molecules that we abbreviate to A, C, G and T. The sequence of the four molecules is what forms our genes. A gene is a sequence of the four molecules and it serves as a recipe for a protein. However, before the cell can produce one of the many different proteins for which it has recipes in its DNA, the sequence must be translated. This happens when the two strands of DNA unwind where the recipe is located and a so-called RNA strand binds to this place and copies the part of the code that makes up the gene. In simple terms, RNA is single-stranded DNA. RNA leaves the cell nucleus and transports the code to the cell's protein factories, the ribosomes, where the code is then translated into a protein. All cells in our body have the same DNA, but the parts of the DNA code that are translated and activated differ from cell to cell. Liver cells have other active genes than skin cells, for example. Not all RNA sequences transport code to the protein factories. Instead, some bits attach themselves to other RNA sequences to stop them from being translated into proteins, or to ensure that the body produces even more of the protein in question. The RNA sequences that are active in a specific type of cell are called the transcriptome. This is what the researchers have been studying in this research project.

Can also help agriculture become greener

The pharmaceutical industry is not the only industry to potentially benefit from the new results. Agriculture can also use the results in their efforts to breed pigs with a reduced climate impact, according to Lingzhao Fang.

- There’s never before been such a comprehensive mapping of the genes that are active in various tissue types. Our results make it possible to more precisely pinpoint the genetic mechanisms that lead to different desirable traits in pigs, he says and continues:

- For example, traits that make them more climate-friendly. Our mapping also paves the way for researchers to edit pig genes far more precisely and in this way develop entirely new properties in the future. Because we now know more about a wide range of traits in pigs, other researchers can more easily use gene-editing techniques such as CRISPR to change genes or insert new sequences with greener properties.

Mapping other animals as well

Pigs are actually not the first animal whose transcriptome Lingzhao Fang and his colleagues have mapped. They started with cows a few years ago, and they plan to map a number of other animals in the coming years.

- We already have a study on chickens in the pipeline. It’s currently being peer-reviewed, but we hope to publish it early next year, he says.

In addition to chickens, pigs and cows, the research team is studying goats, sheep, horses and ducks using the same method. He explains that the ultimate objective is not only to make agriculture greener but also to obtain a better understanding of fundamental animal and human biology. 

- Once we’ve completed the project, we’ll have gained a greater basic understanding of the biology and evolution of a number of animals. This knowledge can be useful in other areas,” he says and continues:

- For example, we have problems with disease transmission between humans and farm animals. Our mapping may provide us with the necessary knowledge to limit and prevent outbreaks in the future.

One of the reasons why Lingzhao Fang is studying farm animals and not wild animals is that it is easy to access tissue samples and large amounts of data. However, the knowledge obtained can also be used in relation to wild and even extinct animals.

- We will gain a fundamental understanding of the biology of several different animals, and these all have wild cousins who basically function in the same way, he concludes.

 

Pigs resemble humans more than mice and rats do. But because pigs are more expensive to use as a model organism in research into new medicines, the small rodents are used more often. However, better knowledge about what makes pigs and humans similar could make pigs even more valuable in developing new medicines for humans. The photo shows a pig that has been bred to study atherosclerosis.

CREDIT

Jesper Rais/AU Communication

The new knowledge makes it possible to breed more climate-friendly pigs in the future.

CREDIT

Lars Kruse, AU Photo

JOURNAL

Nature Genetics

DOI

10.1038/s41588-023-01585-7 

METHOD OF RESEARCH

Data/statistical analysis

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

A compendium of genetic regulatory effects across pig tissues

The climate impact of wild pigs greater than a million cars

UNIVERSITY OF QUEENSLAND

Research News

IMAGE:  "WILD PIGS ARE JUST LIKE TRACTORS PLOUGHING THROUGH FIELDS, TURNING OVER SOIL TO FIND FOOD, " DR O'BRYAN SAID. view more 

CREDIT: THE UNIVERSITY OF QUEENSLAND

By uprooting carbon trapped in soil, wild pigs are releasing around 4.9 million metric tonnes of carbon dioxide annually across the globe, the equivalent of 1.1 million cars.

An international team led by researchers from The University of Queensland and The University of Canterbury have used predictive population models, coupled with advanced mapping techniques to pinpoint the climate damage wild pigs are causing across five continents.

UQ's Dr Christopher O'Bryan said the globe's ever-expanding population of feral pigs could be a significant threat to the climate.

"Wild pigs are just like tractors ploughing through fields, turning over soil to find food," Dr O'Bryan said.

"When soils are disturbed from humans ploughing a field or, in this case, from wild animals uprooting, carbon is released into the atmosphere.

"Since soil contains nearly three times as much carbon than in the atmosphere, even a small fraction of carbon emitted from soil has the potential to accelerate climate change.

"Our models show a wide range of outcomes, but they indicate that wild pigs are most likely currently uprooting an area of around 36,000 to 124,000 square kilometres, in environments where they're not native.

"This is an enormous amount of land, and this not only affects soil health and carbon emissions, but it also threatens biodiversity and food security that are crucial for sustainable development."

Using existing models on wild pig numbers and locations, the team simulated 10,000 maps of potential global wild pig density.

They then modelled the amount of soil area disturbed from a long-term study of wild pig damage across a range of climatic conditions, vegetation types and elevations spanning lowland grasslands to sub-alpine woodlands.

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"Our models show a wide range of outcomes, but they indicate that wild pigs are most likely currently uprooting an area of around 36,000 to 124,000 square kilometres, in environments where they're not native," Dr O'Bryan said.

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The University of Queensland

The researchers then simulated the global carbon emissions from wild pig soil damage based on previous research in the Americas, Europe, and China.

University of Canterbury PhD candidate Nicholas Patton said the research would have ramifications for curbing the effects of climate change into the future.

"Invasive species are a human-caused problem, so we need to acknowledge and take responsibility for their environmental and ecological implications," Mr Patton said.

"If invasive pigs are allowed to expand into areas with abundant soil carbon, there may be an even greater risk of greenhouse gas emissions in the future.

"Because wild pigs are prolific and cause widespread damage, they're both costly and challenging to manage.

"Wild pig control will definitely require cooperation and collaboration across multiple jurisdictions, and our work is but one piece of the puzzle, helping managers better understand their impacts.

"It's clear that more work still needs to be done, but in the interim, we should continue to protect and monitor ecosystems and their soil which are susceptible to invasive species via loss of carbon."

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The research has been published in Global Change Biology (DOI: 10.1111/gcb.15769).

World’s feral pigs produce as much CO2 as 1.1m cars each year, study finds

Researchers estimate the invasive species releases 4.9m metric tonnes of greenhouse gas annually by uprooting soil

Feral Vietnamese pot-bellied pigs roam in Puerto Rico, where they reproduced at such a rate the government declared a health emergency. Photograph: Carlos Giusti/AP

Donna Lu
@donnadlu
Mon 19 Jul 2021 

The climate impact of wild pigs around the world is equivalent to the greenhouse gas emissions of 1.1m cars annually, according to new research.

Modelling by an international team of researchers estimates that feral pigs release 4.9m metric tonnes of carbon dioxide each year globally by uprooting soil.

Researcher Dr Christopher O’Bryan of the University of Queensland said feral pigs were one of the most widespread vertebrate invasive species on the planet.


Florida's feral hogs: a pervasive pest – but a profitable one for some

“Pigs are native to Europe and parts of Asia, but they’ve been introduced to every continent except Antarctica,” he said.

“When we think of climate change, we tend to think of the classic fossil fuel problem. This is one of the additional threats to carbon, and to climate change potentially, that hasn’t really been explored in any global sense.”

Feral hogs uproot soil while searching for food, in a process O’Bryan likens to “mini tractors that are ploughing soil”. Doing so exposes microbes in the soil to oxygen. The microbes “reproduce at a rapid rate and then that can produce carbon emissions [in the form of] CO2.”

“Any form of land-use change can have an effect on carbon emissions from the soil,” O’Bryan said. “The same thing happens when you put a tractor through a field or you deforest land.”

The researchers estimate that wild pigs are uprooting an area upwards of 36,000 sq km (14,000 sq miles) in regions where they are not native.

Oceania had the largest area of land disturbed by wild pigs – roughly 22,000 sq km – followed by North America. The pigs in Oceania accounted for more than 60% of the animal’s estimated yearly emissions, emitting nearly 3m metric tonnes of CO2, equivalent to about 643,000 cars.

The findings of the study, published in the journal Global Change Biology, were drawn from three models. One model predicted wild pig density globally across 10,000 simulations, based on existing information about wild pig populations and locations.

A second model converted pig density into an area of disturbed land, and a third estimated the amount of CO2 emitted when soil is disturbed.

Nicholas Patton, a PhD student at the University of Canterbury, said there was some uncertainty in the modelling as a result of the variability of the carbon content in soils and the densities of wild pigs in different areas.

“Areas that are peat bogs or black soils … especially ones that have a lot of moisture, they’re a sink for carbon,” said Patton. “When pigs get in there and root around, they have a lot more potential for that carbon to be released [than from other soils].”

In addition to their climate impacts, the destructive impact of wild hogs has been well documented. O’Bryan said managing the animals was a challenge that would involve prioritising whichever of their impacts was deemed most significant.

“If all we care about is agriculture, then the cost and the benefits of managing pigs will be different than if all we cared about was carbon emissions, than if all we cared about was biodiversity.

“At the end of the day, feral pigs are a human problem. We’ve spread them around the world. This is another human-mediated climate impact.”

Province unveils new wild pig strategy


WATERLOO REGION — The province is rooting out the wild pig problem before they get a hoof-hold in the province.

The Ministry of Natural Resources and Forestry is asking for public input into a new strategy to deal with wild pigs, and accompanying updates to the Invasive Species Act.

Ontario’s strategy to address the threat of invasive wild pigs is meant to proactively address the threat before wild pigs establish stable populations in the province.

“Based on experiences from other jurisdictions, it is clear that the least costly and most effective approach for managing wild pigs is to act early,” the province writes in the strategy.

The United States Department of Agriculture estimates more than $1.5 billion is lost each year to wild pigs either through damage or lost farming produce. Pigs love to eat agricultural crops and trample the plants and dig up the ground in the process. They also cause significant environmental and water quality damage by rooting up landscapes. They also prey on and compete with native species.

The province’s strategy has four main objectives:

prevent the introduction of pigs into the natural environment

address the risk posed by Eurasian wild boar in Ontario

use a co-ordinated approach to remove wild pigs from the natural environment

leverage expertise and resources by collaborating across ministries, with federal agencies, other jurisdictions, and industry stakeholders, and partners

Much of the strategy is focused on the first objective: preventing the introduction of pigs into the natural environment.

A key centrepiece is to add wild pigs to the Invasive Species Act. This will make intentionally introducing pigs to the environment illegal and give owners clear actions if a pig is accidentally released. It will also give enforcement officers the authority to address any issues of illegal pig releases.

Other activities include developing and distributing guidelines for the best management practices for keeping pigs outdoors. The province says keeping pigs outdoors poses a much higher risk of pigs escaping.

The strategy also proposes outreach about the dangers of keeping pigs as pets, and also letting pig keepers and producers know their legal responsibilities if a pig escapes.

The province says that in other jurisdictions, there is evidence that humans have intentionally released pigs into the wild. For example, in the United States, “wild pig populations increased in 2008 and 2009 when the hog market crashed.”

According to the strategy, hunting wild pigs will become illegal, and the province will phase out possession of Eurasian wild boar species.

The full draft strategy can be seen on the Environmental Registry of Ontario listing #019-3468 and comments will be accepted until June 7 2021.

Leah Gerber’s reporting is funded by the Canadian government through its Local Journalism Initiative. The funding allows her to report on stories about the Grand River Watershed. Email lgerber@therecord.com

Leah Gerber, Local Journalism Initiative Reporter, Waterloo Region Record

Family pigs prefer their owner's company as dogs do, but they might not like strangers

Both dogs and pigs stay close to their owner if no other person is present; but if a stranger is also there, only dogs stay near humans, pigs prefer to stay away

EÖTVÖS LORÁND UNIVERSITY (ELTE), FACULTY OF SCIENCE

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IMAGE: RESEARCHERS AT ELTE DEPARTMENT OF ETHOLOGY IN BUDAPEST COMPARED HOW YOUNG COMPANION DOGS AND COMPANION PIGS SEEK HUMAN PROXIMITY IN A NOVEL ENVIRONMENT. view more 

CREDIT: PHOTO: TÜNDE SZALAI

Researchers at ELTE Department of Ethology in Budapest compared how young companion dogs and companion pigs seek human proximity in a novel environment. It turned out that both dogs and pigs stay close to their owner if no other person is present; but if a stranger is also there, only dogs stay near humans, pigs prefer to stay away. The study reveals that living in a human family is not enough for early developing a general human preference in companion animals, species differences weigh in.

Dogs are known for being especially social with humans from a very early age. Even those with limited contact to humans readily approach and seek human proximity and dogs can also recognize familiar over unfamiliar humans. This special sociability of dogs has been assumed to be the result of both their domestication and socialization with humans during early development. "We were curious if being kept as a family member from a very early age, like dogs, would induce similar proximity-seeking behaviours towards their owner in another social domestic species, the pig"-explains PhD student Paula Pérez Fraga.

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Researchers at ELTE Department of Ethology in Budapest compared how young companion dogs and companion pigs seek human proximity in a novel environment.

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Photo: Balázs Somorjai

Nowadays, the domestic pig, especially the miniature variant, is a popular companion animal that occupies a similar social niche in the human family as the family dog. This new role of the pig creates the need to better understand the pig-human relationship in the household environment, and especially the relationship of the pigs with their owners. "The miniature pigs that are part of our Family Pig Project are raised in human families since their 6-8 weeks of age. This does not only provide a unique opportunity to investigate the pig-human relationship, but it also allows us to directly compare their human-oriented behaviour to those of dogs"- says Attila Andics, principal investigator of the MTA-ELTE 'Lendület' Neuroethology of Communication Research Group.

"In this study, the animals were led into a novel room, where their owner was paired with a familiar object or with an unfamiliar person, on two separate occasions. The subjects could freely choose to be anywhere in the room, e.g. staying near or further away from any of the humans or the object"-says Linda Gerencsér, research fellow at the Research Group. "We found that both pigs and dogs preferred to stay near their owner over the familiar object. However, neither species preferred their owner over the stranger, but for seemingly different reasons. Dogs preferred to stay near both humans over being elsewhere, whereas pigs rather stayed away from the social partners, which might reflect slight fear towards the unfamiliar human." Interestingly, the research also revealed a difference in how the two species behaved near their owner. "Pigs needed more physical contact" - adds Pérez Fraga. "They touched the owner with the snout, in a similar manner as they do with conspecifics, and they climbed to the owner's lap."

Watch our study's video abstract: https://www.youtube.com/watch?v=-srppJ6UupY.

This is the first study to investigate the proximity seeking behaviours of miniature pigs towards their owner. "The similar previous experience of both pigs and dogs might lead to a similar role of the owner for the two species" - adds Gerencsér. "However, being kept as a family member might not be enough for developing a general preference for human company in pigs. Species predispositions, including that dogs, have a longer socialization period and humans are more salient as a social stimulus for them, might play an important role."

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The study reveals that living in a human family is not enough for early developing a general human preference in companion animals, species differences weigh in.

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This study was published on the 30th of November in Scientific Reports titled "Human proximity seeking in family pigs and dogs", written by Paula Pérez Fraga, Linda Gerencsér, and Attila Andics. The research was funded by the National Research, Development and Innovation Office, the Hungarian Academy of Sciences (Lendület Program) and the Eötvös Loránd University (ELTE).