Ben C. West

Andrea L. Cooper

James B. Armstrong

MANAGING WILD PIGS

A TECHNICAL GUIDE

HUMAN-WILDLIFE INTERACTIONS MONOGRAPH

NUMBER 1 
ACKNOWLEDGMENTS

As with any such endeavor, we are indebted to a large number of people and organizations for their support of 

this publication and their assistance in bringing it to fruition. We thank the Berryman Institute, Mississippi State 

University, Utah State University, Auburn University, USDA/APHIS/Wildlife Services, the Alabama Wildlife 

Federation, the Wildlife Damage Working Group of The Wildlife Society, the Renewable Resources Extension 

Act (RREA), and the Association of Fish and Wildlife Agencies for their financial and moral support of this 

publication. Frank Boyd was instrumental to the original concept for this publication and continued to provide 

valuable advice and guidance during its development. Michael Conover was key to this guide being published 

as part of the new Monograph series of the journal Human-Wildlife Interactions. We could not have possibly 

produced this document without the able assistance of our designer, Kathy Jacobs, and our editor, Tom Knecht; 

the quality of this publication is due in large part to their efforts. Many people generously provided photographs and 

illustrations, including Carol Bannerman, Tyler Campbell, Steve Gulledge, Billy Higginbotham, Chris Jaworowski, 

Dana Johnson, Dan McMurtry, Eddie Parham, Rod Pinkston, and the Southeastern Cooperative Wildlife Disease 

Study. Finally, we benefitted greatly from comments and suggestions on drafts provided by Carol Bannerman, Jerry 

Belant, Tyler Campbell, Joe Corn, Rob Denkhaus, Stephen Ditchkoff, John Dunlap, Kris Godwin, Bill Hamrick, 

Ed Hartin, Billy Higginbotham, Skip Jack, Chris Jaworowski, Dana Johnson, Steven Lapidge, Jack Mayer, Dan 

McMurtry, Gary Moody, Jim Miller, Rod Pinkston, and Ron Regan. Their generous sharing of time and expertise 

added immeasurably to the accuracy and completeness of this publication.

The mention of commercial products in this publication is for the reader’s convenience and is not intended as an 

endorsement of those products nor discrimination against similar products not mentioned. 

This publication should be cited as:

West, B. C., A. L. Cooper, and J. B. Armstrong. 2009. Managing wild pigs: A technical guide. Human-Wildlife 

Interactions Monograph 1:1–55.

To obtain additional copies of this publication, please visit www.berrymaninstitute.org/publications, where an 

electronic copy may be downloaded at no charge. Printed copies may also be ordered at that website for a nominal 

shipping and handling fee. 

ISBN# 0-9742415-1-2

Published by The Berryman Institute

Starkville, MS and Logan, UT

Several cover photos provided by Steve Gulledge and Chris Jarowowski 

Editing by Tom Knecht, Words by Tom

Design and Layout by Kathy Jacobs Design & Marketing
CONTENTS

Preface 1

Wild Pigs in North America 3

Biology and Natural History 5

Range ......................................................................................................................................................................5

Physical Characteristics .........................................................................................................................................6

Breeding and Reproduction....................................................................................................................................8

Dispersal .................................................................................................................................................................9

Home Range ...........................................................................................................................................................12

Mortality and Survival............................................................................................................................................13

Feeding Habits ........................................................................................................................................................13

Wild Pig Damage 15

Ecological Damage..................................................................................................................................................15

Agricultural Crops.................................................................................................................................................16

Livestock.................................................................................................................................................................17

Damage to Forest Restoration................................................................................................................................18

Disease Threats to Humans and Livestock............................................................................................................18

Swine Brucellosis.............................................................................................................................................19

Pseudorabies ....................................................................................................................................................20 

Classical Swine Fever ......................................................................................................................................20

Trichinosis........................................................................................................................................................21

Damage Management Techniques 22

Legal Considerations..............................................................................................................................................23

Population Dynamics and Management Strategies................................................................................................23

Lethal Techniques...................................................................................................................................................24

Trapping ...........................................................................................................................................................24

 Bait.............................................................................................................................................................25

 Cage Traps.................................................................................................................................................26

 Door Designs.............................................................................................................................................27

 Trigger Designs..........................................................................................................................................29

 Putting It All Together: Three Trap Designs ...........................................................................................29

Snares .............................................................................................................................................................32 

Shooting and Hunting......................................................................................................................................33

 Aerial Shooting .........................................................................................................................................33

 Night Shooting ..........................................................................................................................................34

 Judas Pig....................................................................................................................................................35 
 Hunting With Dogs...................................................................................................................................36

Toxicants ..........................................................................................................................................................37

Nonlethal Techniques.............................................................................................................................................38

Fencing .............................................................................................................................................................38

Harassment.......................................................................................................................................................39

Vaccination.......................................................................................................................................................39

Contraception..................................................................................................................................................39

Summary 41

Literature Cited 43

Appendix 51

Authors 54
1

This manual was written to help people, especially natural resource 

professionals, who are interested in managing wild pigs (Sus scrofa). 

However, we expect that it will be read by a wide variety of people, 

including wildlife biologists, land managers, farmers, hunters, policymakers, 

academicians, and others. Given this diversity of readership, developing 

this guide was a balancing act between offering detailed information 

supported by the scientific literature on the one hand and summarizing as 

simply as possible what is known about wild pigs and their management 

on the other. In the end, we are hopeful that the publication is detailed 

enough to be useful to those with a deep interest in wild pigs but 

also succinct enough for those simply interested in a comprehensive 

management resource.

Since their introduction to North America, wild pigs have become 

one of the more serious wildlife problems in the United States. Conover 

(2002) opines that the vast majority of wildlife in North America have 

many positive values that ultimately outweigh the costs of the problems 

they may cause and thus provide a net benefit to society. From that 

perspective, wildlife damage management is the strategy of alleviating 

problems sometimes caused by wildlife while retaining or enhancing 

their positive benefits. Conover (2002) further explains, however, that 

a few wildlife species cause problems that outweigh their positive values 

and should be considered pests. Although we recognize that wild pigs 

provide recreational benefits to some hunters and landowners (see Rollins 

PREFACE

Since their introduction 

to North America, wild 

pigs have become one of 

the more serious wildlife 

problems in the United 

States. 

Chris Jaworowski
2

et al. 2007), one could argue that the scope and 

severity of problems caused by pigs outweigh their 

benefits in many areas. In these cases, managers 

may decide that population reduction or eradication 

is the preferred management objective, and we 

created this manual to support such efforts. 

While there is a technical distinction between 

Eurasian wild boars, feral pigs, and their hybrids, all 

have similar impacts on ecosystems, native wildlife, 

agricultural commodities, and other resources. Thus 

for the sake of practicality we use the term “wild pigs” 

to refer collectively to feral pigs, Eurasian wild boars, 

and hybrids. Please note, however, the information 

herein is not intended for management of the collared 

peccary (javelina; Tayassu tajacu), a native inhabitant 

of the American Southwest, Mexico, and Central and 

South America. 

The body of scientific work regarding wild pigs 

is impressive, particularly in the arenas of natural 

history, biology, ecology, and environmental impact. 

Wolf and Conover (2003) and, more recently, 

Mayer and Shedrow (2007) have compiled excellent 

bibliographies for individuals wanting an exhaustive 

review of all the scientific literature pertaining 

to wild pigs. Despite this abundance of scientific 

literature, many questions remain about the effective 

management of wild pigs, and managers must often 

invent techniques and strategies on the fly. 

Because we intend this as a technical guide for 

management, we have included both references to the 

scientific literature and anecdotal information from 

the field. Many of the management options we discuss 

have been largely untested by the rigors of scientific 

investigation, and we expect researchers to continue 

testing and refining those and other techniques. In the 

meantime, we recognize that management is both art 

and science, and both are equally valid and important 

to individuals interested in managing wild pigs.
3

WILD PIGS IN NORTH AMERICA

Wild pigs are not native to the Americas (Mayer and Brisbin 1991). 

Pigs are thought to have been first domesticated from the Eurasian wild 

boar about 8,000 to 10,000 years ago (Barrett 1978, Larson et al. 2005, 

Minagawa et al. 2005). In addition, new genetic data have revealed a 

history of widespread multiple centers of independent pig domestications 

across Eurasia (Giuffra et al. 2000, Larsen et al. 2005). Given their 

adaptability and ability to survive in the wild, they were a popular livestock 

for American settlers colonizing new areas and were probably first 

introduced into the New World by Christopher Columbus in 1493 in 

the West Indies. In the ensuing centuries, pigs were released throughout 

the United States, particularly in the southeastern states (Hanson and 

Karstad 1959, Wood and Lynn 1977, Mayer and Brisbin 1991). Following 

the initial flurry of releases throughout the 1500s, settlers, farmers, and 

Native Americans promoted the spread of pigs by open range practices that 

persisted in some states as recently as the 1960s. By the early 1980s, wild 

pigs ranged from the Coastal Plain of Virginia south to Florida, and west 

to Texas and California (Sweeney and Sweeney 1982). Today, though the 

range of wild pigs appears to be continually expanding, the South remains 

the epicenter of wild pig populations.

The establishment of Eurasian wild boar populations occurred 

mostly after the release of domestic pigs into the wild. The establishment 

of a boar population in the wild likely first occurred when some were 

brought to North Carolina from Germany in 1912 for hunting purposes 

Today, wild pigs are 

both numerous and 

widespread throughout 

North America.

Chris Jaworowski
4

(Jones 1959); descendants from this population 

were later introduced into California in 1925 or 

1926 (Bruce 1941, Seymour 1970; Pine and Gerdes 

1973). More recently, Eurasian wild boars were 

introduced into other areas of the United States, 

and many hybrid populations occur throughout 

the range of wild pigs as a result of cross-breeding. 

Pure strains of Eurasian boar reportedly are rare; 

nevertheless, at least a few small localized populations 

of pure animals exist in the United States (e.g., 

Michigan), having originated from farm-raised wild 

boar brought down from Canada (Mayer 2009). 

Today, wild pigs are both numerous and 

widespread throughout North America. It is 

exceedingly difficult to conduct population censuses 

of any species of wildlife, including wild pigs. This 

difficulty, coupled with ongoing population growth 

and range expansion of wild pigs, makes it nearly 

impossible to estimate the number of wild pigs in 

the United States and to definitively state where 

they do and do not occur. Regardless, evidence is 

compelling that wild pigs are abundant in many areas 

and are expanding their range into areas heretofore 

not occupied. As early as the 1950s, concentrations 

of wild pigs in the Southeast were high, though the 

reported density of 75 to 100 animals per square mile 

(Hanson and Karstad 1959) was probably unrealistic 

and a result of poor population estimation techniques. 

Nevertheless, pigs are numerous, so much so that 

several decades ago Decker (1978) reported wild pigs 

to be the most abundant, free-ranging, introduced 

ungulate in the United States. Mayer and Brisbin 

(1991) suggested a United States population between 

1 and 2 million wild pigs in 1991, but that number 

quickly became obsolete and the current population 

is likely much greater; for example, Taylor (2003) 

speculated that the wild pig population in Texas alone 

numbered 1.5 million animals. 
5

BIOLOGY & NATURAL HISTORY

Wild pigs are remarkable in the diversity of their physical appearance and 

behavior. The purpose of this publication is not to provide an exhaustive 

review of the substantial body of literature on the natural history and 

biology of wild pigs but to provide sufficient information to understand the 

basic character of the animal. Readers interested in greater detail about 

wild pig biology, natural history, and behavior should turn to the excellent 

summaries by Mayer and Brisbin (1991), Sweeney et al. (2003), and Mayer 

and Brisbin (2009).

RANGE 

Because wild pigs are highly adaptable, suitable habitat occurs throughout 

much of North America. Since their introduction in the southeastern 

United States, wild pigs have expanded their range to many other regions 

of the country, particularly in the past few decades. The Southeastern 

Cooperative Wildlife Disease Study (SCWDS) has monitored wild pig 

populations since 1982 and has documented a steady advance into new 

regions (www.uga.edu/scwds/dist_maps.htm); currently, pigs exist in at 

least 39 states (Fogarty 2007, Gipson et al. 1998). Although many have 

presumed that pigs were a southern species and that harsh winters would 

limit their expansion northward, pig populations now exist in the northerly 

climates of Michigan and North Dakota. 

Wild pigs are remarkable 

in the diversity of their 

physical appearance and 

behavior. 
6

Wild pigs are numerous and widespread across the country. The Southeastern Cooperative Wildlife Disease Study (SCWDS) has monitored 

wild pig populations since 1982 and has documented a steady advance into new regions. Recently, SCWDS has created a dynamic mapping 

system to monitor the expansion of pig populations continuously. For more information, visit www.feralswinemap.org.

Southeastern Cooperative 

Wildlife Disease Study

The SCWDS has created a dynamic 

online database to monitor wild pig 

distribution in the United States (www.

feralswinemap.org). Wildlife professionals 

with state and federal agencies continually 

provide data for the online database, and 

it thus represents a potentially valuable 

tool for monitoring the distribution and 

expansion of wild pigs in North America. 

However, the ultimate accuracy and hence 

value of this tool is dependent upon the 

participation and input of natural resource 

professionals nationwide, so they are 

encouraged to contribute data about pig 

distribution in their state and region.

PHYSICAL CHARACTERISTICS

Wild pigs come in all colors, shapes, and 

sizes. Because of their varied ancestry, 

Once thought to be primarily a southern species, pigs have been expanding their 

range and now exist in many northern climates.

individual wild pigs vary widely in physical appearance and 

morphometrics. Although some differences exist among Eurasian 

wild boars, wild pigs of domestic ancestry, and hybrids (Mayer and 

Brisbin 1991), these differences are mostly unimportant from a 
7

management perspective and will not be 

discussed in detail here. Readers interested 

in more information about the differences 

in the Eurasian wild boar and other wild 

pigs should examine Mayer and Brisbin 

(1991), Mayer and Brisbin (1993), and 

Sweeney et al. (2003).

Wild pigs most frequently are blackish 

in color, but individuals may be nearly any 

color or combination of colors. Eurasian 

wild boars typically have a coat of brown 

to black hairs with white or tan distal tips 

(i.e., grizzled coloration), whereas wild pigs 

from domestic ancestry are characterized by 

uniformly colored hair (Mayer and Brisbin 

1991). Furthermore, pelage color can be 

variable throughout the life of an individual. 

For example, some young wild boars 

have a striped juvenile coat coloration 

that disappears with age and changes to 

the aforementioned adult grizzled coat 

coloration pattern. In contrast, other wild 

piglets can have a coat similar in color to 

that of adults from the same population 

(Mayer and Brisbin 1991, 1993). 

Pigs have 44 permanent teeth, and 

the development of the upper and lower 

canines of males are of particular interest 

(Sweeney et al. 2003). These teeth grow 

continually and, because of friction between 

the upper and lower canines, can become 

quite sharp, particularly the lower canines. 

These canines, or tusks, can grow to 4 

inches or more in length out of the socket 

(Mayer and Brisbin 1988) and are at the 

heart of much of the lore about wild pigs. 

Fighting among rival mature males for 

breeding opportunities is the apparent 

evolutionary cause of the size difference 

seen between the sexes in wild pig tusks 

(Herring 1972). Such male-male fights can 

be fierce, and tusk scars are common on the 

bodies of adult boars.

Wild pigs come in a variety of colors and patterns, ranging from black to 

multicolored. 

The lower canines or tusks of male wild pigs can grow quite long and sharp. These 

tusks are used in bouts with rival males and are at the heart of much of the lore 

about wild pigs.

Chris Jaworowski

Eddie Parham

Chris Jaworowski
8

Piglets often have striped coats; the striping typically disappears 

as they age.

Individual wild pigs vary widely in their physical 

dimensions and weight, depending on their ancestry 

and local environment. As a general rule, males are 

larger and weigh more than females, but much overlap 

exists. Average total lengths (measured from the tip 

of the nose to the end of the fleshy part of the tail) 

for adult wild pigs range from about 50 to 75 inches, 

and average weights from about 75 to 250 pounds 

(Sweeney 1970, Mayer and Brisbin 1991). 

Individual wild pigs can grow quite large, 

depending on available food resources. For example, 

one pig killed in South Carolina tipped the scale at 

893 pounds (Rutledge 1965). Records are challenged 

quite often, most famously by “Hogzilla,” a supposedly 

gigantic wild pig shot in southern Georgia. The 

original Hogzilla was claimed to weigh in excess of 

1,000 pounds and be 12 feet in length, but the pig 

was buried before these assertions could be verified. 

National Geographic, curious about the outrageous 

claims, assembled a research team to exhume the 

carcass and estimate its live size and weight. They 

concluded that Hogzilla was real, but researchers 

estimated the live weight to be about 800 pounds and 

the total length to be between 7.5 and 8 feet (Minor 

2005). When such gigantic pigs are reported, it is 

almost always the result of people feeding captive pigs, 

growing them to enormous sizes, and then releasing 

them into the wild.

BREEDING AND REPRODUCTION

Wild pigs are perhaps the most prolific large mammal 

on Earth. Pig populations can grow rapidly in good 

habitat, and this population growth and subsequent 

dispersal can result in pigs quickly colonizing and 

populating new areas (Waithman et al. 1999). Such 

impressive growth capability is possible because pigs 

possess traits that yield high recruitment rates. To 

a large extent, these traits are an artifact of their 

domestic heritage, namely that, (1) pigs reach sexual 

maturity at a young age, (2) females can farrow 

multiple times a year, (3) females can have large litters, 

and (4) natural mortality rates often are relatively 

low. Good habitat conditions can enhance all of these 

characteristics and result in irruptive population 

growth (Bieber and Ruf 2005).

Wild pigs are perhaps the most 

prolific large mammal on earth. 

Puberty occurs early in wild pigs, particularly 

under good habitat conditions. In general, puberty 

occurs between 6 and 10 months of age (Barrett 

1978), although Giles (1980) reported puberty in wild 

females as young as 3 months. Although females begin 

breeding as soon as puberty occurs, sexually mature 

males are often prohibited from breeding by older, 

more dominant individuals (Barrett 1978). 

Wild pigs are physiologically capable of 

reproducing twice each year, although individuals 

in most populations produce only a single litter 

annually (Springer 1977, Taylor et al. 1998). Wild 

pigs can breed year-round, and farrowing has been 

observed throughout the year. Nevertheless, most 

Chris Jaworowski
9

Wild pig populations have incredible potential for growth. In good conditions, 

adult females can farrow multiple times a year and produce large litters, and 

juvenile females can breed at an early age. As a result, pig populations can 

quickly grow and expand their range.

USDA/APHIS/Wildlife Services, Carol Bannerman

populations exhibit breeding patterns in 

which farrowing peaks during winter and 

early spring and occurs again in a secondary 

period in midsummer (Barrett 1978, 

Sweeney et al. 1979, Taylor et al. 1998), 

although this timing may vary with locale 

(Sweeney et al. 2003). 

Domestic pigs have been selectively 

bred for large litters, and this trait 

remains in feral populations. Although 

individual sows may sometimes have 

litters of ≥10 piglets, litter sizes in the 

wild typically range from 3 to 8. Litter size 

may increase in association with greater 

female body size, condition, and habitat 

quality (Sweeney et al. 2003, Bieber 

and Ruf 2005). Wild pigs with Eurasian 

wild boar ancestry tend to have slightly 

smaller litters than pigs from domestic 

ancestry, with most wild boar females 

farrowing litters of 4 to 5 piglets (Sweeney 

et al. 2003). Like other reproductive 

traits, litter sizes, and thus reproductive 

potential, increase with improved 

habitat quality (Bieber and Ruf 2005).

DISPERSAL

Social structures in wild pig populations 

are characterized by lone males and groups 

(often called “sounders”) of females and 

piglets. These sounders consist of up to 3 

related generations and typically number 

8 or fewer individuals with 1 to 3 adults. 

Piglets normally are weaned around 3 

months of age, at which time individual 

yearling females either remain with the 

group or begin the process of dispersal. 

Kaminski et al. (2005) reported that most 

yearling females (79%) remained with their 

family group, and this arrangement appears 

to be an all-or-nothing proposition; female 

yearlings in a group either all dispersed 

Wild pigs generally travel in large family groups, often called “sounders,” 

consisting of several adult females and multiple juveniles.

USDA/APHIS/Wildlife Services, Dana Johnson
10

Wild female pigs in southern swamps construct nests or beds 

by cutting and piling palmetto fronds to protect their young from 

weather and predation. In other areas leaves, grasses, and twigs 

may be used and placed over a small depression in the ground.

Chris Jaworowski

Wild pigs leave field signs that are unique and identifiable, thus making it relatively 

easy to determine whether wild pigs inhabit an area.

Rooting is the most common and recognizable field sign created 

by wild pigs.

Pigs create wallows to cool their body temperature and rid 

themselves of biting insects.

Chris Jaworowski

Chris Jaworowski

Wild pigs deposit characteristic scat that is a reliable sign of their 

presence in an area.

Chris Jaworowski
11

As part of their scent marking behavior, male wild pigs use their 

tusks to remove the bark and expose the wood of small trees.

Mud rubs on trees are a good indicator of the presence of wild 

pigs. They rub on trees to remove excess mud from their coats 

after wallowing. Mud rubs on trees can give you an idea as to the 

relative size of pigs in your area. Mud rubs that are 3 to 4 feet off 

the ground indicate the presence of mature pigs.

Eddie Parham Eddie Parham

USDA/APHIS/Wildlife Services, Dan McMurtry and Chris Jaworowski

Tracks left by wild pigs and white-tailed deer often are easily 

identified. Pig tracks are generally more rounded at the tips of the 

hooves, and they often display more widely spread dew claws.

Sometimes, though, it can be difficult to distinguish between 

them. This track, left by a wild pig, could easily be mistaken for 

that of a white-tailed deer. 

USDA/APHIS/Wildlife Services, Dan McMurtry Chris Jaworowski
12

or all remained with the family group. Females that 

disperse usually do so with their sisters and create 

another family group together. Males essentially 

always disperse from the family group, usually around 

16 months of age (Gabor et al. 1999).

HOME RANGE

Wild pigs are opportunistic generalists with regard 

to diet and habitat; consequently, their home range 

size may depend on a number of factors, including 

habitat quality, food availability, and population 

density. The average home range size for wild pigs in 

North America varies from a few hundred to several 

thousand acres (Kurz and Marchinton 1972, Singer 

et al. 1981, Baber and Coblentz 1986; Boitani et al. 

1994, Hayes 2007, Gaston 2008). Poor habitat quality, 

limited food availability, and low population density 

lead to larger home ranges. Human activity can greatly 

impact home ranges, as pigs reduce movements and 

home ranges in situations where human activity is high 

(Wood and Brenneman 1980, Hayes 2007, Gaston 

2008). 

Within their annual home range, wild pigs are 

almost nomadic and have seasonal home ranges 

that may or may not overlap. Gender and age seem 

to have little impact on the size of wild pig home 

ranges, although Saunders and McLeod (1999) did 

report that body mass was positively correlated to 

home range size in these animals. Although many 

factors influence the seasonal movements of pigs, 

food availability is of primary importance, followed by 

thermoregulation needs. Pigs have no functional sweat 

glands, so they are sensitive to high temperatures 

and rely on behavioral adaptations to cope with hot 

weather. The impact of temperature on seasonal 

movements is not clear, though some have reported 

that pigs shift summer home ranges to areas with 

cooler ambient temperatures and with greater 

availability of water (Hughes 1985). The impact of 

temperature on daily movements is much clearer, as 

thermoregulation greatly influences daily movements 

and can lead to nocturnal behavior during summer 

months (Sweeney et al. 2003). 

Geist (1977) reasoned that Suids should exhibit 

territorial behavior, but evidence for such in wild pig 

populations has been mixed. Some studies have found 

that female home ranges overlapped, and some have 

thus concluded that female wild pigs are not territorial 

(Barret 1978, Graves 1984, Baber and Coblentz 1986, 

Boitani et al. 1994). More recent studies, though, have 

hypothesized that while females within a particular 

sounder are not territorial, sounders as a group do 

indeed establish and defend territories. Biotani et al. 

(1994) reported that sounders did not hold territories 

and instead had overlapping home ranges, whereas 

Ilse and Hellgren (1995) and Gabor et al. (1999) did 

document exclusive home ranges and thus evidence 

for territoriality. Sparklin et al. (2009) specifically 

studied the territoriality of sounders, and concluded 

that wild pigs are territorial on the level of sounders 

but not individuals. Questions yet remain about the 

Although many have debated the role of territoriality in the 

ecology of wild pigs, recent research has shown that while 

wild pigs may not be territorial on the individual level, they do 

appear to be so on the sounder level. 

Chris Jaworowski
13

impact of resource availability on pigs’ tendencies 

toward territorial behavior.

MORTALITY AND SURVIVAL

In most areas and populations, the most significant 

cause of mortality in wild pigs is hunting. However, 

because of their prolificacy, wild pig populations in 

good habitats can endure extremely high rates of 

hunting harvest (Barrett and Pine 1980), and in 

most cases hunting alone cannot control populations. 

Bieber and Ruf (2005) estimated that, in good habitat 

conditions, adult survival would have to be reduced to 

<10% to counter population growth. In some cases, 

hunting has had a significant impact on pig populations 

(Belden and Frankenberger 1989, Belden 1997), but 

it is unclear how the impact of hunting mortality 

interacts with and is influenced by habitat quality. 

In addition to direct mortality, the effects of high 

pressure from humans (either hunting pigs or hunting 

other game) may indirectly reduce survival of pigs, 

regardless of gender or age (Gaston 2008). 

Wild pig populations in good 

habitats can endure extremely 

high rates of hunting harvest.

Predation has little impact on most pig 

populations, although researchers have documented 

predation by alligators, black bears, and mountain 

lions (Sweeney et al. 2003). Indeed, in some specific 

situations, wild pigs can represent a significant prey 

item, as Maehr et al. (1990) documented in Florida 

panthers. The impact of disease and parasites on 

wild pig populations is poorly understood, though 

it probably can be substantive in specific situations. 

Disease seems to pose the greatest risk to both young 

(<6 months) and older (>2 years) individuals, though 

this, too, is largely speculative (Sweeney et al. 2003). 

FEEDING HABITS

Wild pigs are opportunistic omnivores that feed 

primarily by rooting and grazing, which contributes 

to their role as a problematic species. Their rooting 

behavior, in particular, is a principal reason they 

are considered a pest. Schley and Roper (2003) 

summarized diet analyses in 21 different articles based 

on research conducted across 8 European countries 

and noted that wild pigs will eat almost any organic 

substance, depending on availability. Sweeney et al. 

(2003) likewise provided an overview of wild pig 

feeding studies, all of which reported an incredibly 

varied diet. Even so, some generalizations can be 

made. Vegetation certainly dominates pig diets — 

in volume, ≥85% of wild pigs’ diet is composed of 

vegetable matter — but animals, both vertebrate 

and invertebrate, also constitute a regular food item 

(Schley and Roper 2003). Invertebrates represent 

prominent food items for wild pigs; insects and 

earthworms commonly show up in stomach contents. 

Researchers sometimes find larger mammals in wild pig 

stomachs, presumably as a result of scavenging. More 

When available, mast is a common food item for wild pigs. 

In some cases, pigs may outcompete native wildlife for these 

food resources.
14

commonly, though, pigs consume small mammals and 

herptiles, sometimes from scavenging, sometimes from 

direct predation (Schley and Roper 2003, Wilcox and 

Van Vuren 2009). 

Evidence suggests that wild pigs are largely 

indiscriminate in their food selection. Some 

researchers have suggested that pigs prefer mast when 

available, particularly acorns, although others argue 

this interannual variation is only reflective of forage 

availability, not diet preference (Barrett 1978, Belden 

and Frankenberger 1990, Schley and Roper 2003). 

Whatever the case, it is clear that mast constitutes 

a very common food item when available and that 

its annual availability has a significant impact on the 

body condition, reproductive potential, and movement 

patterns of wild pigs (Wood and Brenneman 1980, 

Baber and Coblentz 1987, Jedrzejewska et al. 1997). 

Some have suggested that wild pigs compete with 

other, more desirable wildlife species for mast, but 

such competition has not been fully documented 

(Sweeney et al. 2003). 

Finally, wildlife researchers and managers have 

long speculated about the impact of wild pigs on 

ground-nesting birds, particularly as it relates to nest 

predation. Without question, wild pigs do sometimes 

consume eggs and chicks (Thompson 1977, Tolleson 

et al. 1993); still, little conclusive evidence exists to 

suggest that pigs prefer these or any other food item. 

Most likely, pigs consume eggs and chicks at a rate 

proportional to incidental encounter, and in areas with 

dense pig populations, this incidental consumption 

could be problematic. Be that as it may, researchers 

are undecided about the impact of wild pigs on 

populations of ground-nesting birds. Future research 

may bring clarity to this issue. 
15

WILD PIG DAMAGE

ECOLOGICAL DAMAGE

Wild pigs cause problems in North American ecosystems in a variety of 

ways, largely because these systems did not evolve with pigs and are not 

adapted for their rooting behavior (Baber and Coblentz 1986). Impacts 

to ecosystems can take the form of decreased water quality, increased 

propagation of exotic plant species, increased soil erosion, modification of 

nutrient cycles, and damage to native plant species (Patten 1974, Singer 

et al. 1984, Stone and Keith 1987, Cushman et al. 2004, Kaller and Kelso 

2006) 

Wild pigs are perhaps the greatest vertebrate modifiers of natural 

plant communities (Bratton 1977, Wood and Barrett 1979, Stone 

and Keith 1987). Rooting, trampling, and compaction influence plant 

regeneration, community structure, soil properties, nutrient cycling, and 

water infiltration (Seward et al. 2004). Wild pigs may induce the spread 

of invasive plant species because invasive exotics typically favor disturbed 

areas and colonize more quickly than many native plants (Hone and 

Pederson 1980, Coblentz and Baber 1987, Stone and Keith 1987). Habitat 

damage is particularly important in wet areas where plant communities 

and soils tend to be more sensitive to disturbance. In Florida, wild pigs 

contributed to the decline of at least 22 plant species and 4 amphibian 

species listed as rare, threatened, endangered, or of special concern 

(USDA 2002). Impacts are particularly significant to endangered species 

Wild pigs are perhaps 

the greatest vertebrate 

modifiers of natural 

plant communities.

Chris Jaworowski
16

on islands such as Hawaii where a high number of 

plant and wildlife species are endemic (Mungall 2001). 

Recovery of plant communities is sometimes possible 

after pig populations have been reduced or eliminated, 

but the species composition of plant communities may 

be permanently altered. 

Pigs can cause problems for native wildlife by 

competition for resources, direct predation, and 

the spread of disease and parasites (Hanson and 

Karstad 1959, Sweeney et al. 2003). Wild pigs may 

compete with native wildlife for hard and soft mast 

and many other important food items (Belden and 

Frankenberger 1989, Yarrow and Kroll 1989). As 

noted earlier, wild pigs can be significant predators of 

ground-nesting bird nests (Thompson 1977, Tolleson 

et al. 1993), although the impact of this predation on 

the populations of ground-nesting birds is yet unclear. 

In addition, pigs also prey upon small mammals, 

salamanders, frogs, fish, crabs, snakes, turtles, and 

white-tailed deer fawns (Lucas 1977, Hellgren 1993, 

Jolley 2007, Jolley et al. 2010). In the southeastern 

United States, wild pigs have become significant 

Wild pig rooting along streams can decrease water quality, 

increase erosion, and damage sensitive plant communities.

Chris Jaworowski

predators of sea turtle eggs on mainland and island 

beaches along the Atlantic coast (Lewis et al. 1996). 

Specifically, pigs have threatened the nesting success 

of several endangered turtles including the loggerhead, 

green, leatherback, hawksbill, and the Kemp’s 

ridley by destroying up to 80% of nests in some 

regions of Florida (USDA 2002). Although little 

scientific literature exists to document the problem, 

reports from the field indicate that wild pigs have a 

significant impact on gopher tortoises through habitat 

degradation and direct predation. This, in turn, may 

negatively impact Mississippi gopher frogs, eastern 

indigo snakes, and other species that have a symbiotic 

relationship with tortoises. 

Wild pigs also cause problems in aquatic systems 

via increased soil erosion and bacterial contamination 

(Kaller et al. 2007). Wild pig activity in streams has 

impacted a variety of aquatic flora and fauna, most 

notably freshwater mussels and insects (Kaller and 

Kelso 2006, Kaller et al. 2007). Moreover, wild pigs 

have caused the level of fecal coliforms in some streams 

to exceed human health standards (Kaller 2005).

AGRICULTURAL CROPS

In addition to impacting ecosystems, wild pigs can 

damage timber, pastures, and, especially, agricultural 

crops (Bratton 1977, Lucas 1977, Thompson 1977, 

Schley and Roper 2003). A conservative estimate 

of wild pig damage to agricultural crops and the 

environment in the United States is $1.5 billion 

annually (Pimentel et al. 2002, Pimentel 2007). 

Wild pigs cause damage by directly consuming 

crops, damaging fields by rooting and digging, and 

trampling crops (Whitehouse 1999). Pigs will travel 

long distances to consume attractive foods; one 

study reported that pigs traveled 6 miles to forage on 

sorghum (Mungall 2001). In a survey of extension 

agents in Texas, Rollins (1993) found the most 

common complaint was damage to crops, including 

hay, small grains, corn, and peanuts. Crops such as 

vegetables, watermelons, soybeans, cotton, tree fruits, 

and conifer seedlings were also affected by wild pigs. 
17

In addition to directly damaging crops, 

pigs can damage infrastructure such as 

fences, irrigation ditches, roads, dikes, and 

other structures. Rooting and wallowing 

in agricultural fields creates holes that, if 

unnoticed, can damage farming equipment 

and pose potential hazards to equipment 

operators (Nunley 1999).

A conservative estimate 

of wild pig damage to 

agricultural crops and 

the environment in the 

United States is $1.5 

billion annually. 

LIVESTOCK

Wild pigs sometimes prey on livestock, 

including lambs, goats, newborn cattle, 

and exotic game. Predation on young 

livestock animals usually occurs on calving 

or lambing grounds where wild pigs may 

be attracted by afterbirth (Beach 1993). 

Though predation is usually concentrated 

on young animals, livestock giving birth are 

sometimes killed and consumed (Wade and 

Bowns 1985). 

Wild pig predation on livestock can be 

difficult to verify because the entire carcass 

is usually consumed, leaving little evidence. 

In addition, pigs will scavenge carcasses 

killed by other animals. If the whole carcass 

is not consumed, however, wild pigs usually 

follow a characteristic feeding pattern 

that can be used to identify the source of 

the damage. They typically kill their prey 

by biting and crushing the skull or neck 

(Frederick 1998). The carcass typically 

The aggressive rooting tendencies of wild pigs cause damage to roadsides, 

dikes, and other earthen structures.

Chris Jaworowski

Chris JaworowskI

Wildlife openings planted in small grains are favored rooting areas for wild pigs in 

the fall. Rooting damage can lead to equipment damage and costly repairs for land 

managers.

will be skinned and the rumen or stomach contents consumed 

(Wade and Bowns 1985). Obviously, wild pig tracks and scat in the 

immediate vicinity can help identify incidents of predation.

In addition to directly preying on livestock, wild pigs can cause 

damage to livestock fencing. Because of their size and strength, wild 

pigs can damage even robust fences, thus compromising the fence’s 

ability to contain livestock and exclude predators. Although no one 

has estimated the economic impact of this damage, it has potential 

to be significant in terms of fence repair costs and escaped livestock 

(Beach 1993).
18

DAMAGE TO FOREST RESTORATION

Hard mast (e.g., acorns and hickory nuts) is an important food 

source for wild pigs; thus attempting to regenerate hardwoods from 

seed may be difficult if pigs are present. In areas where mast or fruit 

have already germinated, rooting activities may dislodge and damage 

young seedlings. In some areas, rooting significantly reduces oak 

regeneration (Huff 1977, Sweitzer and VanVuren 2002). Rooting 

also accelerates decomposition of leaf litter, resulting in a loss of 

nutrients from the forest floor and upper soil horizons (Singer et al. 

1984), which may make it more difficult for 

seedlings to grow and survive.

Seedlings of both hardwoods and 

pines, especially longleaf pines, are very 

susceptible to pig damage through direct 

consumption, rooting, and trampling 

(Whitehouse 1999, Mayer et al. 2000, 

Campbell and Long, 2009). This is 

problematic in all forests where it occurs, 

but particularly in longleaf pine forests, an 

ecosystem already in peril. Longleaf pines 

dominated about 92 million acres in the 

United States before European settlement 

but now occupy less than 3 million acres, 

mostly in the southeastern region of 

the country (Landers et al. 1995). The 

abundant populations of wild pigs across 

the region have made the restoration and 

management of longleaf pine forests even 

more difficult and tenuous. 

For some time, wildlife managers 

questioned whether pigs consumed tree 

seedlings, given that woody material 

is seldom found in stomach analyses. 

However, researchers suspected that pigs 

chew the roots of seedlings, swallow the sap 

and starches, and then spit out the woody 

tissue. To support this idea, researchers have 

found and documented balls of masticated 

roots where wild pigs have been rooting 

among woody plants (Adams et al. 2006). 

DISEASE THREATS TO HUMANS 

AND LIVESTOCK

Wild pigs are capable of carrying numerous 

parasites and diseases that potentially 

threaten the health of humans, livestock, 

and wildlife (Forrester 1991, Williams 

and Barker 2001, Sweeney et al. 2003,). 

Humans can be infected by several of these, 

including diseases such as brucellosis, 

leptospirosis, salmonellosis, toxoplasmosis, 

Wild pigs can cause significant damage to forests. Perhaps most important, they 

can impair regeneration through consumption of mast and the destruction of 

seedlings, particularly those of longleaf pines.

Steve Gulledge

Wild pigs can quickly damage pasturelands while rooting for earthworms, grubs, 

roots, and tubers. Their rooting can reduce the production of forage, as well as 

make the harvest of hay difficult or impossible. Rooting damage can also lead to 

damage of hay cutters and bailing equipment.

USDA/APHIS/Wildlife Services, Carol Bannerman
19

Wild pigs can harbor many diseases that are dangerous to 

humans, livestock, or other wildlife. The presence of wild 

pigs in an area can make it difficult or impossible to eradicate 

certain diseases from livestock, and their contamination of the 

environment with disease agents can have serious consequences. 

In 2006, after hundreds of people nationwide were infected with 

E. coli following the consumption of bagged spinach, investigators 

identified wild pigs as a likely source of the contamination 

(California Food Emergency Response Team 2007).

sarcoptic mange, E. coli, and trichinosis. Diseases of 

significance to livestock and other animals include 

pseudorabies, swine brucellosis, tuberculosis, vesicular 

stomatis, and classical swine fever (Nettles et al. 1989, 

Davidson and Nettles 1997, Williams and Barker 2001, 

Davidson 2006). 

Many of the disease management strategies used 

in the livestock industry, such as vaccinations and 

animal husbandry, are not an option for wild pigs. 

Thus wild pigs can serve as a reservoir and amplifier 

for many diseases, making it difficult or impossible to 

eradicate disease in livestock and humans in areas with 

wild pigs (Hone et al. 1992, Corn et al. 2005, Hutton 

et al. 2006, Wyckoff et al 2009). The role that wild 

pigs could play in spreading and perpetuating exotic 

diseases that may emerge in the future is particularly 

troublesome. For example, foot-and-mouth disease, 

which was eradicated in the United States in 1929, 

would be essentially impossible to eradicate again if it 

reemerges in areas with wild pigs. If foot-and-mouth 

disease were to reemerge in the United States, it 

would result in a reduction of $14 to 21 billion in 

United States farm income (Paarlberg et al. 2002).

Because of the myriad of viruses, bacteria, and 

parasites that wild pigs carry and can infect humans, 

individuals should take precautions to protect 

themselves from infection when handling them, 

including either live animals or carcasses. Surgical 

gloves should always be worn and probably offer 

sufficient protection for the hunter who handles a pig 

or two every year. However, the wildlife professional 

who handles a large number of pigs may opt for more 

substantive protection, including perhaps a surgical 

mask, gown or coveralls, and eye protection. At 

the very least, agencies and organizations involved 

with the management of wild pigs should educate 

their employees about the risks of zoonotic diseases, 

establish protocols for handling these animals, and 

determine minimum requirements for personal 

protective equipment when doing so.

A comprehensive discussion of important diseases 

relative to wild pigs is beyond the scope of this 

publication. Nevertheless, the following paragraphs 

provide basic information about a few diseases that 

hunters, landowners, and farmers commonly inquire 

about or should be aware of. Those interested in 

a more detailed and technical summary of disease 

implications of wild pigs should reference the articles 

by Davis (1993), Corn et al. (2005), Hutton et al. 

(2006), and Stallknecht and Little (2009), or the 

myriad of articles available in the Journal of Wildlife 

Diseases. In addition, the field guides by Davidson and 

Nettles (1997) and Davidson (2006) provide a broad 

overview of the causative agents, field signs, and other 

important aspects of many diseases in wild pigs. 

Swine Brucellosis

Swine brucellosis is caused by the bacterium 

Brucella suis and should not be confused with 

bovine brucellosis, or the diseases found in goats 
20

and dogs caused by other Brucella spp. bacteria. 

This is primarily a reproductive tract disease that 

causes abortion, stillborn or weak piglets, infertility, 

inflammation of the testicles, and lameness. Infected 

animals are long-term carriers. Chronic infection 

can produce shrunken testicles. Sows can develop 

small abscesses in the uterine lining that can lead to 

puss exudate in the uterus. Aborted fetuses often 

look normal, but the afterbirth may show blood clots 

and hemorrhages. Transmission of swine brucellosis 

occurs through ingestion of recently discharged bacteria 

in aborted fetuses, urine, and semen or via sexual 

contact (Davidson and Nettles 1997, Davidson 2006).

Swine brucellosis has been found in multiple 

populations in Arkansas, Alabama, California, Florida, 

Georgia, Hawaii, Louisiana, Mississippi, South 

Carolina, and Texas but is likely not limited to these 

states. The domestic swine industry has endeavored to 

eradicate brucellosis within domestic populations, but 

this endeavor is hindered by contact with infected wild 

pigs (Davidson and Nettles 1997, Davidson 2006). 

Human infection by Brucella bacteria is possible 

and not uncommon. Health officials in Florida, for 

example, documented that 8 of 10 human cases of 

brucellosis in 2007 were linked to wild pig hunting 

activities (Florida Department of Health 2008). 

Humans with the disease typically have flu-like 

symptoms including intermittent fever, headaches, 

muscle and joint soreness, and weakness. Though 

few humans die of infection, the disease is often 

chronic and debilitating. Hunters should wear rubber 

gloves and wash with soap as soon as possible after 

handling a carcass and also ensure the meat is cooked 

thoroughly before consumption (Davidson and Nettles 

1997, Davidson 2006).

Pseudorabies

Infection of pseudorabies, a disease caused by a herpes 

virus, in wild pigs is common throughout their range 

in the United States (Stallknecht and Little 2009). 

In domestic pigs, this disease produces clinical signs 

that vary from unnoticeable to fatal infections; in wild 

pigs, though, pseudorabies rarely results in disease or 

mortality (Stallknecht and Little 2009). When disease 

develops, young pigs are most severely affected and 

often display fever, vomiting, tremors, incoordination, 

convulsions, and death in most piglets less than 4 

weeks old. Adult pigs usually survive but can have 

fever and upper respiratory tract inflammation. Of 

particular importance to domestic swine producers, 

infection in pregnant sows results in abortion or 

mummified fetuses. In domestic and wild mammals 

other than swine, the virus produces an acute 

infection of the central nervous system that produces 

a loss of appetite, depression, staggering, spasms, and 

a death rate of nearly 100%. Also known as “mad 

itch,” pseudorabies infections can cause self-mutilation 

through persistent scratching, biting, or rubbing 

(Davidson and Nettles 1997, Davidson 2006). 

The virus is spread through nasal or oral 

secretions, particularly in stressed animals, and 

through the genitalia. In wild pigs, transmission seems 

to occur mostly through sexual contact (Romero et al. 

2001). Ingestion of infected carcasses can also result 

in transmission. Other animals that become infected 

usually die from the disease, which can include cattle, 

sheep, horses, dogs, cats, foxes, raccoons, skunks, rats, 

and mice (Davidson and Nettles 1997, Davidson 2006). 

Millions of dollars are spent annually to detect 

and prevent pseudorabies in domestic swine. Because 

many individuals in wild populations are latent 

carriers, relocation of wild pigs without appropriate 

testing threatens to spread the disease and is thus, in 

most states, illegal. Even in domestic herds, control of 

pseudorabies is difficult; in wild populations, control 

of the virus is essentially impossible. Thus the most 

rational strategy to manage the impact of pseudorabies 

is to eliminate the transport of live wild pigs and to 

reduce or eradicate their populations.

Classical Swine Fever

Also commonly known as hog cholera, classical swine 

fever is a viral disease once prevalent among domestic 

swine in the United States; however, it was eradicated 

in the 1970s (Nettles et al. 1989). Affected animals 

become lethargic, feverish, and lose their appetite. 
21

Vomiting and diarrhea cause animals to become 

weaker and weaker. This disease generally progresses 

rapidly, and infected animals usually die 10 to 20 days 

after exposure. Convulsions may occur in the terminal 

stage. Chronic infections with milder symptoms can 

occur, with recovered pigs becoming virus carriers 

(Davidson and Nettles 1997, Davidson 2006).

Because of its eradication in the United States, 

classical swine fever is considered a foreign animal 

disease and must therefore be reported to state 

or federal animal health authorities for diagnostic 

investigation. This virus is easily transmitted from 

pig to pig by direct contact and can also be spread by 

exposure to contaminated pens, trucks, or feeders 

(Davidson and Nettles 1997, Davidson 2006). 

Trichinosis

Trichinosis is caused by a nematode, or round worm, 

parasite. Infected wild pigs and other animals rarely 

show definitive signs of infection. A variety of animals 

are susceptible to trichinosis, including wild pigs, 

bears, wolves, wolverines, raccoons, foxes, rats, and 

birds. Hosts become infected by eating larvae in the 

muscle of infected animals. Adult worms live in the 

intestinal tract, and the larvae form cysts in muscle 

tissue. More larvae can be found in the most active 

muscles of the body, including the tongue, diaphragm, 

jaw, and intercostal muscles. The larvae remain viable 

for years within muscle tissue until ingested and 

passed on to the next animal. While trichinosis does 

not produce illness in wild pigs and other infected 

animals, it is an important disease because of human 

infections that cause severe flu-like symptoms and 

potentially lead to death (Davidson and Nettles 1997, 

Davidson 2006).

In the past, most cases of trichinosis in humans 

were caused by consumption of undercooked domestic 

pork products. However, the incidence of trichinosis 

in domestic stock has been greatly reduced in recent 

years due to improved husbandry practices. In wild 

pigs, though, trichinosis still occurs commonly. As 

a result, all meat should be handled with gloves and 

cooked to an internal temperature of 170° Fahrenheit 

to prevent human infection.
22

DAMAGE MANAGEMENT 

TECHNIQUES

Although several methods can be used to control wild pig populations, 

individuals with experience in wildlife damage management recognize that 

many options within the standard suite of management techniques are 

either unsuitable or ineffective for pigs. Nevertheless, several effective 

lethal and nonlethal methods exist. Managers must consider their 

management objectives when deciding which strategies to pursue and 

which techniques to employ. 

Nonlethal methods include exclusion devices such as fences, guard 

animals to protect livestock, and vaccinations to prevent disease spread. 

However, guard animals are generally not practical for use against wild pigs 

in large, brushy pasture situations like the sheep and goat country of Texas 

(Littauer 1993), and vaccinations are not yet ready for widespread use. 

Frightening devices are ineffective, and there are no chemical repellents or 

toxicants registered for wild pig management in the United States (Barrett 

and Birmingham 1994), although many researchers are trying to develop 

such options. Habitat manipulation is impractical given the adaptability of 

the species.

Most strategies to manage damage caused by wild pigs involve lethal 

control. Lethal methods include trapping, shooting, and hunting with dogs. 

The efficacy and feasibility of each of these methods is dependent upon 

the terrain, available labor and funding, and the management objectives. 

Most strategies to 

manage damage caused 

by wild pigs involve 

tactics to reduce pig 

populations.

Chris Jaworowski
23

Certainly, the vast majority of successful efforts 

to control wild pigs in the United States involve 

shooting, trapping, or some combination of these 

methods, and thus these techniques will be described 

in greatest detail.

LEGAL CONSIDERATIONS

Obviously, individuals interested in managing wild 

pigs should understand the laws and regulations 

relevant to their locale. The wild pig problem has 

evolved rapidly over the past decade or two, both in 

terms of the pigs’ distribution and abundance and in 

our understanding of the issues. This rapid evolution 

and increasing complexity, coupled with the fact that 

wild pig management falls within the jurisdiction 

of individual state governments, have resulted in a 

plethora of laws unique to each state, and those laws 

are rapidly evolving. From a national perspective, the 

laws and regulations governing the management of 

wild pigs are complicated and dynamic. As a result, 

it is not possible in this publication to outline what 

can and cannot legally be done to control wild pigs. 

Indeed, any attempt at such an accounting would 

quickly be rendered obsolete as states continue 

to form new laws and regulations in an attempt to 

manage wild pigs and the problems they cause.

Still, some generalizations about the management 

of wild pigs can be drawn. Typically, state wildlife 

agencies have jurisdiction over wild pigs, although 

such authority is held by the agricultural commission 

in some states. In either case, these agencies generally 

recognize wild pigs as problematic and in need of 

intensive management. As a result, state regulations 

generally make it relatively easy for individuals to 

conduct pig control activities, especially on private 

property. Nevertheless, readers should contact the 

appropriate state wildlife and fisheries agency or 

agricultural commission with questions about wild 

pig management in their state. It is also important to 

monitor changes in regulations throughout the year, as 

many states are continuing to experiment with rules to 

encourage and promote pig control.

POPULATION DYNAMICS AND 

MANAGEMENT STRATEGIES

It can be helpful to understand population dynamics 

of wild pigs while designing and implementing control 

strategies. Using population modeling, Bieber and 

Ruf (2005) illustrated the influence of habitat quality 

on the population growth of wild pigs and thus the 

likelihood of population control. As mentioned earlier, 

environmental conditions such as food availability and 

climatic conditions greatly influence the reproductive 

capacity of wild pigs, particularly the reproductive 

capacity of juvenile females. As such, habitat quality 

has great influence on the potential for population 

reduction and should be considered when developing 

and implementing management programs.

In areas with poor habitat and limited food 

availability, juvenile females generally do not breed. 

Thus, adult mortality strongly influences the size and 

growth of wild pig populations in these situations. 

Hunting for wild pigs is a popular sport, particularly in the 

South. Although it may be an effective tactic as part of a larger 

management strategy, recreational hunting alone is unlikely to 

control wild pig populations. Nevertheless, the stress created 

by hunting can cause pigs to move away from or restrict their 

movement within sensitive areas, reducing the likelihood of 

damage to such areas. 

Billy Higginbotham
24

In such poor habitat, management programs such as 

recreational hunting that remove mostly adults have 

the potential of successfully reducing the population. 

This may explain why, in some situations, recreational 

hunting alone has resulted in low pig populations 

(Belden and Frankenberger 1989, Belden 1997).

The greatest challenge for managers interested in 

controlling wild pigs occurs in areas with good habitat 

conditions and abundant food. In these areas and 

during periods of particularly abundant food (such 

as during good mast years), juvenile breeding can 

contribute more to population growth than that of 

adults (Bieber and Ruf 2005). Under these conditions, 

even a mortality rate of 90 to 100% of adult females 

may not cause a population decline, as reproduction 

in juvenile females would be sufficient to sustain 

the population. As a result, recreational hunting, 

which normally removes mostly adult pigs, is usually 

ineffective as a population control method in good 

habitat (Hanson et al. 2009). Under such good habitat 

conditions, managers will have to focus on removing 

both adults and juveniles, as this is likely the only way 

to affect a population reduction. 

Another implication of the population dynamics of 

wild pigs is that supplemental food sources can affect 

management efforts. In areas where supplemental food 

is consistently available year to year — either in the 

form of agricultural crops or feed meant for livestock 

or other wildlife — it can be exceedingly difficult 

to remove enough animals from an established pig 

population to induce a population decline. In these 

situations, land managers may have to couple pig 

removal with long-term changes in land use or feeding 

practices to achieve success in reducing populations of 

wild pigs.

Although population eradication often is a bestcase scenario, it is challenging to accomplish in most 

situations because of pigs’ reproductive capacity, 

immigration from surrounding areas, and difficulty 

of finding and removing the last few remaining 

individuals (Hone 1983, Saunders and Bryant 1988, 

Choquenot et al. 1993). Nevertheless, eradication of 

wild pig populations has been accomplished in some 

areas by using a combination of removal strategies 

(Schuyler et al. 2002, Cruz et al. 2005, McCann and 

Garcelon 2008). Eradication efforts probably have 

greatest opportunity for success in areas where pig 

populations are just beginning to become established 

or on islands (Schuyler et al. 2002, Cruz et al. 2005). 

Even in the absence of eradication, aggressive control 

programs can result in significant depopulation, 

which would solve many problems caused by wild 

pigs (Hone 1983). In Texas, for example, efforts to 

reduce the population sizes of wild pigs over 2 years 

resulted in a 66% decline in damage to agricultural 

crops and pastures (Higginbotham et al. 2008). In 

any depopulation program, it is important to conduct 

ongoing population surveys to assess the success of 

the program and the degree of population reduction 

(Richardson et al. 1997).

LETHAL TECHNIQUES

Trapping

Trapping is the most popular method for removing 

wild pigs from a population, and trapping programs 

— followed by euthanasia, not relocation — can 

reduce population density. Choquenot et al. (1993) 

found that an intense trapping program can reduce 

populations by 80 to 90%, but that some individuals 

are resistant to trapping; thus, trapping alone is 

unlikely to be successful in entirely eradicating 

populations. Unfortunately, little scientific literature 

exists to document which trap types and designs are 

most effective. Without a doubt, like most trapping, 

pig trapping is more art than science, and managers 

initiating a pig control program will quickly develop 

their own preferences and opinions. To that end, this 

section provides an overview of trapping strategies 

and techniques that managers can draw upon and 

apply in their own unique situations.

In general, cage traps, including both large corral 

traps and portable drop-gate traps, are most popular 

and effective, but success varies seasonally with 

the availability of natural food sources (Barrett and 
25

Birmingham 1994). Cage or pen traps are based on 

a holding container with some type of a gate or door 

(Mapston 1999). Snares can also be effective but 

should be used cautiously in areas where livestock, 

deer, or other nontarget animals are present. Access 

points such as fence underpasses or pen entrances not 

used by nontarget animals are ideal locations for snares. 

Pig trapping is more art than 

science.

Though traps can be effective and are probably 

the most common and preferred tactic for pig 

removal, managers should understand some potential 

problems associated with using them. Traps can 

be heavy and cumbersome, may entrap a variety of 

nontarget animals, and may elicit trap shyness among 

wild pigs. In addition, when several animals are 

caught, some may climb on top of others and escape 

over the side if the trap has no roof or other design 

Placement of traps is important to success. Note that this trap 

was placed against an opening the pigs had pushed through 

this fence.

Chris Jaworowski

feature to minimize this occurrence (Mapston 1999). 

Furthermore, pigs may not be attracted to bait when 

natural sources of food are abundant, and trapping 

during these times can be ineffective. For example, 

Barrett and Birmingham (1994) documented that 

capture success is low during periods of heavy acorn 

production. Despite these problems and limitations, 

trapping is probably the most important tool in 

managers’ arsenals for controlling wild pigs, and 

proper design can minimize many of these problems.

Bait

Many food items can be used for attracting wild pigs to 

traps or shooting sites. Shelled corn is likely the most 

popular choice, as it is effective and widely available, 

but reports from the field suggest that nontarget 

animals often find and consume the corn before pigs 

do. Since pigs are such generalist feeders, other food 

items that are perhaps less attractive to nontarget 

species can be used as bait. Carrion and sour grain are 

common selections; fermented corn or soybeans, in 

particular, are a favorite among many field biologists. 

Although these items are messier to work with than 

corn, they can reduce the attraction of nontarget 

animals to bait sites. In addition, some managers have 

developed mechanical feeding devices to reduce the 

consumption of corn by smaller nontarget animals like 

raccoons and wild turkeys. 

A popular baiting device is a roll barrel, which is 

simply a large barrel (typically a 55-gallon drum) or 

section of large (8 inch or greater diameter) capped 

PVC pipe with multiple small holes (commonly 1 

inch in diameter) distributed throughout and filled 

with corn or other pellet-type bait. Pigs are large and 

strong enough to move the barrel and thus extract 

corn from the barrel, while smaller animals are unable 

to do so.

Prebaiting can significantly increase the 

effectiveness of both trapping and shooting programs 

and should usually be considered standard practice 

when initiating a trapping program. Locking open 

the door of a trap and feeding bait for a period before 
26

setting the trigger increases visitation to the trap and 

the likelihood of multiple captures (Mapston 1999). 

Placement of the bait within the trap relative 

to the location of the trigger mechanism can be 

important, too. Some trappers advocate placing 

small amounts of bait in and around the door 

area, leading to larger quantities of bait around 

the trigger mechanism and as far from the door as 

possible. However, other trappers prefer just the 

opposite strategy: placing relatively large amounts 

of bait near the door with small amounts around 

the trigger mechanism. The rationale of this latter 

strategy is to maximize the opportunity for capturing 

larger numbers of pigs in a single trapping event. 

Theoretically, the larger amounts of bait near the door 

will attract the first few individuals without triggering 

the door, while following individuals will go to the 

remaining areas with feed around the trigger, thus 

making it possible to capture the entire group. 

Cage Traps 

Cage traps are by far the most common type of trap 

used to capture wild pigs. Stationary corral-type 

traps and more portable box traps have long been 

used for wild pig control with good success. Many, 

many different trap designs have been invented and 

promoted, and each trap inventor is likely convinced 

his or her design is superior to all others. In reality, 

however, several designs have been effective, and 

the exact design specifications are probably not as 

important as a few key principles. 

First, when possible, traps should be large enough 

to trap and hold multiple pigs. The construction 

and maintenance of these stationary traps requires 

a significant investment in time and resources, and 

the ability to remove multiple pigs with each trap 

armament makes that investment more cost effective. 

Although mobility is sometimes important and may 

require smaller traps that are easy to move from site 

to site, the general rule for pig traps is that bigger is 

better. 

Second, the trap must be sturdy enough to 

contain pigs once capture occurs. Adult pigs are large 

and powerful, and trap materials and construction 

techniques must be able to withstand the forces 

exerted by captive animals. At a minimum, side panels 

should be constructed of 4-gauge welded fencing or 

its equivalent (typically sold at farm suppliers as cattle 

or hog panels). The trap should be anchored, at a 

minimum, with steel fence posts, and the framework 

should be made of material equivalent in strength to 

2x4-inch or, better still, 4x4-inch dimensional lumber. 

Doors should be constructed of material equivalent 

in strength to 3⁄4-inch plywood or greater. In areas 

with particularly large pigs, even heavier materials 

should be used for gates and frames (Barrett and 

Birmingham 1994). Though wood certainly has been 

used successfully as a construction material for traps, 

steel is the better alternative for both strength and 

long-term durability.

Third, in most cases, delayed triggers should be 

used so multiple pigs can enter before the door trigger 

is engaged, thus increasing the probability of capturing 

multiple pigs each time. Two trigger designs that allow 

this are typically used — root sticks and trip wires — 

and they are described in greater detail later in 

this section.

Finally, traps should be designed so that pigs 

cannot escape by jumping or climbing. One method to 

prevent escape is the installation of a wire top (Barrett 

and Birmingham 1994), but this can cause unwanted 

mortality when deer, bears, or other nontarget animals 

are captured. In areas where capture of deer is a 

concern, the sides of the trap should be constructed 

of fence panels about 6 feet in height, which will 

enable most deer to escape while containing most 

pigs. In rectangular traps, pigs often congregate in the 

corners, thus providing an opportunity for individuals 

to climb on the backs of other pigs and escape over 

the top, even when using 6-foot or higher walls. To 

combat this problem, many managers advocate the 

construction of circular traps because pigs are less 

likely to congregate and thus escape by climbing out. 

A final option is the installation of “jump bars,” which 

are simply 4 bars installed parallel with the top edge 

of each trap panel. The bars are placed approximately 
27

USDA/APHIS/Wildlife Services, Dana Johnson 

USDA/APHIS/Wildlife Services, Chris Jaworowski

Adult pigs are large and powerful. Trap materials and construction techniques 

must be able to withstand the forces exerted by captive animals.

Jump bars are an effective tool to prevent pigs from escaping from rectangular 

cage traps. Four bars are installed a few inches away from the 4 top edges of the 

trap, and the intersections above each corner prevent animals from escaping 

from the backs of their fellow captives.

USDA/APHIS/Wildlife Services, John Dunlap

6 inches inside the trap edge and serve as a 

barrier to pigs attempting to climb out the 

top of the trap. In order to keep the bars 

secured in place, they are connected to 

each other at the four intersecting points 

by a pin or wire. Jump bars have proven 

quite effective at preventing escape from 

rectangular traps (personal communication, 

J. Dunlap, USDA/APHIS/Wildlife 

Services biologist, Florida).

In addition to large, stationary, corraltype traps, portable traps have been used 

effectively and can be moved from one area 

to another. These traps can be useful where 

wild pig occurrence is intermittent, when 

managers want to transport live pigs to 

another location, or when the terrain makes 

the installation of corral traps difficult (as in 

rocky soils where it is hard to install t-posts). 

Often, the activities involved with 

setting up traps will push wild pigs into 

less disturbed areas. Adequate time should 

be given for them to return to the area 

before giving up and moving the traps to 

new locations. The best placement for all 

traps is in areas of high use, with signs like 

well-worn trails and wallows. When in 

operation, traps should be checked daily 

to be reset and rebaited when necessary. 

Loose barbed wire fencing around the 

outside of traps can help prevent livestock 

from entering and will protect bait material 

from some nontarget animals. When 

trapping is not occurring, trap doors should 

be locked open to prevent the accidental 

entrapment of nontarget animals and to 

perhaps allow resident pigs to become 

accustomed to an open trap.

Door Designs

An essential element of all cage traps is a 

door that allows pigs to enter the trap and, 

upon activation of the trigger, prevents 
28

Wooden sliding doors like this one are easy to construct and work very well as 

part of any corral-style trap. 

The design of lift or rooter gates allow pigs to lift the door and enter the trap 

while preventing captured pigs from escaping.

Chris Jaworowski

Chris Jaworowski

Swing doors pivot toward the inside of the trap, are held open with a trigger 

mechanism, and close with the aid of a spring mechanism. This door style is 

commonly used on portable cage traps.

Chris Jaworowski

pigs from leaving. The most important 

characteristic of trap doors is that they 

be large enough to allow individual pigs 

to enter without inadvertently triggering 

the door. As a general rule, door openings 

should be 32 inches wide or greater and at 

least 34 inches tall. 

Although a plethora of door designs 

have been created, most fall within 3 broad 

categories: swing doors, fall doors, or lift 

doors. 

Swing doors pivot toward the inside 

of the trap, are held open with a trigger 

mechanism, and close with the aid of a 

spring mechanism. Once closed, the spring 

mechanism and design keep the door closed 

and prevent pigs from exiting the trap.

Fall doors are initially suspended via a 

trigger line. Once triggered, gravity causes 

the door to slide or swing, thus entrapping 

individual pigs. 

Lift or rooter doors exploit pigs’ rooting 

tendency to create 1-way entries into traps. 

These doors are hinged at the top and 

tilted inward to the interior of the trap to 

allow pigs to root underneath the door and 

enter the trap, but not exit. Often, these 

doors are engineered to operate as a hybrid 

and incorporate the action of both fall and 

lift doors. Initially, the door is held open 

and suspended by the trigger line. Once 

the door is triggered and falls, however, 

it operates as a lift door and continues to 

allow pigs to enter the trap but prevents 

pigs from leaving.

As noted above, adult wild pigs can 

be large and strong. All components of 

the trap must be able to withstand the 

forces exerted by these animals, and this 

is especially true of the door mechanism. 

Doors can be easily built with dimensional 

lumber, but the most robust mechanisms 

are custom fabricated from steel to the 
29

Chris Jaworowski

Using simple materials and construction, the root stick is a 

reliable and time-tested triggering device. 

specifications of the trapper. For those managers 

not able or willing to pursue the construction of 

custom trap door mechanisms, commercial products 

are available from a variety of sources, mostly from 

small welding or machine shops scattered across the 

country. An example is the “hog slammer” swing door 

offered by Southern Outdoor Technologies, LLC 

(www.sportsmanscondo.com). Another company, 

Younger Bros. (www.younger-bros.com), offers 

a variety of commercial doors and traps. Readers 

interested in finding a local source for premade trap 

doors should contact others in the local area already 

involved with a pig trapping program; a local fabricator 

may already be making and selling doors or other trap 

components. If not, most welding or machine shops 

could construct such doors with simple plans and 

instructions.

Trigger Designs

Managers typically use 1 of 2 primary trigger designs 

when constructing traps: the root stick and the trip 

wire. In both cases, the trigger causes a line to be 

pulled, which causes the door to fall or swing closed. 

The root stick trigger design uses a stick wedged 

underneath holding stakes in or around the bait. The 

root stick is triggered as pigs in the act of feeding and 

rooting (hence the name “root stick”) push the root 

stick out from underneath the holding stakes and 

allow the door to fall. 

The trip wire is the more sensitive of the 2 

designs and can be triggered with relatively little 

pressure. Many derivations of the trip wire exist, but 

it is essentially a line or wire suspended just above 

the ground with a triggering device that releases and 

allows the door to close when pressure is exerted on 

the line.

Deciding which triggering device to use is largely 

a matter of personal preference and trial-and-error 

experimentation. Some trappers swear that the root 

stick is the better approach, as it takes some time for 

pigs to trip the device and presumably allows more 

individuals to enter the trap and be captured. Others, 

however, have cited evidence that root sticks have 

a low capture rate and thus prefer trip wires as a 

triggering device (personal communication, C. Betsill, 

USDA/APHIS/Wildlife Services biologist, North 

Carolina). In either case, the triggering device should 

be placed on the opposite side of the trap from the 

door, which should provide some delay in tripping the 

trigger and allow as many individuals as possible to 

enter the trap and be captured. 

Putting It All Together: Three Trap Designs

Within the scope of this publication, it is impossible 

to describe all the various trap designs for wild 

pigs; there are likely as many designs as there are 

individuals involved with trapping. Readers interested 

in exploring these possibilities need only search the 

Internet for “feral hog traps” or “wild pig traps” to 

find pictures and diagrams of traps with a wide range 

of sizes, configurations, and construction techniques. 

Instead of attempting to reflect that diversity here, 

we highlight 3 designs that should satisfy the needs of 

anyone interested in trapping pigs by showcasing one 

that is quick, easy, and cheap to construct; one that is 
30

STAKE WITH 

EYELET

GATE

FENCE LINE

PULLEY

STAKE WITH 

HOOK

BAIT BAIT

BAIT

A trip wire in conjunction with a sliding trap door is a relatively simple mechanism that can be constructed from few materials. Every trapper 

has a different approach to constructing the trip wire, and many different configurations can work. 

Also notice in this diagram the baiting strategy employed, which can be used for both trip wires and root sticks. By scattering bait heavily just 

inside the entrance and more lightly around the trip wire, the trapper increases the likelihood of having multiple pigs enter the trap before 

tripping the door. If bait were placed only around the trip wire or root stick, the first individual in would go directly to the bait and trip the 

door, thus leaving less time for other pigs to enter.

Kathy Jacobs
31

Chris Jaworowski

USDA/APHIS/Wildlife Services, Dana Johnson

Using a wooden sliding door and root stick trigger, the poor man’s trap can 

capture multiple pigs in one setting.

The poor man’s trap is relatively simple and cheap to construct, yet it is fully 

capable of capturing many wild pigs. Using 3 cattle panels and a wooden sliding 

door, this trap can be constructed for little money, built by those with limited 

construction or fabrication skills, and moved relatively easily from site to site. For 

a bit more time and money, additional panels can be added to both make the trap 

larger and create a circular shape, thus lessening the tendency to crowd at the 

corners and potentially escape.

portable; and one that is large, complex, and 

expensive but very effective. 

Design 1: The so-called poor-man’s 

special is the essence of a simple and cheap 

pig trap. It is a 3-sided wire trap rigged 

with a wooden drop door. This trap can be 

constructed for little money, built by those 

with limited construction or fabrication 

skills, and moved relatively easily from site 

to site. The trap can be constructed using 

only 3 heavy-duty wire cattle panels, a 

dozen or so t-posts for reinforcement, and 

a homemade wooden drop door outfitted 

with either a root stick or trip wire 

triggering device. Although cheap and easy 

to build, this trap can capture several pigs 

at a time and does a reasonably good job 

of holding them securely, although some 

animals may escape at the corners by piling 

on their fellow captives and hopping out 

from their backs. With just a bit more time 

and effort, this trap can be constructed in 

a circular shape instead of a triangle and 

thus reduce the likelihood of crowding into 

corners and subsequent escape. All in all, 

this trap is a good choice for the landowner 

or managers just embarking upon the 

practice of wild pig trapping and is easily 

modified as needs and conditions change.

Design 2: The portable cage trap is a 

significant step up from the poor-man’s 

special in terms of construction cost and 

complexity. Typically consisting of a welded 

steel frame and heavy wire panels, its 

construction is beyond the reach of those 

without significant fabrication skills. Those 

in need of such a trap may have to contact 

a local welding or fabrication shop about 

constructing one or buy one of the several 

commercially available units; again, a quick 

search on the Internet will yield many 

buying options. One of the traps displayed 

here features a spring-operated swing door, 

while the other incorporates a rooter door. These smaller box traps 

will not allow capture of as many individuals as a larger corral-type 

trap, but they are highly portable and can easily be moved around 

from site to site, a vital characteristic for some managers. In Texas, 

traps like this are used to transport live pigs from the trapping 

location to various collection points, where the pigs are butchered 

and the meat sold to niche restaurants and markets.
32

On this portable cage trap, the designer used a spring-loaded swinging door, 

which can be very effective. 

The portable cage trap can be easily moved from site to site, a vital capability for 

some managers. This particular trap is outfitted with a rooter door.

Chris Jaworowski

Chris Jaworowski

Design 3: The large corral trap outfitted with a robust door 

mechanism, such as the Kerrville Rooter Gate with Missouri 

Trigger, represents a top-of-the-line trap design. It is big enough 

to capture a large group of pigs, has a dual-function door that 

serves as both a fall door and, once triggered, as a lift door, and is 

robust enough to withstand any forces exerted on it. The unique 

door design functions first as a fall door that enables the capture 

of many pigs simultaneously. Once tripped, the door allows other 

pigs to root underneath and enter the trap but prevents captured 

pigs from leaving. In addition, the unique door is composed of 3 

pieces so that smaller pigs, which would otherwise be unable to lift 

such a large door, can also root into the trap. 

Construction of such a door requires fairly 

complicated fabrication, however, so some 

managers may opt for a simpler design or 

choose to purchase one of the many offerings 

on the market. The rest of the trap, however, 

could be assembled by most individuals in a 

few hours. See the appendix for complete 

construction details for this trap.

Snares

Although probably not as widely used as 

some other tools, snares can be useful 

in specific situations, such as in rough 

terrain, where cage traps are impractical, 

or in scenarios where pigs grow wary of 

other trapping techniques. Furthermore, 

snares have distinct advantages over cage 

traps in the arenas of cost and portability. 

For these reasons, leg or, more typically, 

neck snares are often the tool of choice for 

wildlife managers. In Texas, for example, 

neck snares are the second-most-popular 

removal tool used by USDA/APHIS/

Wildlife Services, ranking only behind aerial 

shooting. 

Managers interested in using snares 

to remove wild pigs should note that 

snares set on land are not legal in many 

states. Individuals should check with local 

conservation officers to ascertain the 

specific legality of snares in their states 

as well as to inquire about the necessity 

of permits or licenses. Even when legally 

permissible, snares should be used with 

caution in areas where livestock, deer, and 

other nontarget species are present. 

An ideal application for neck snares 

occurs under fences where wild pigs are 

accessing areas or on trails that pigs are 

traveling extensively. These areas can be 

identified by tracks and drag marks on the 

ground, hair on the fences, or arched-up 
33

USDA/APHIS/Wildlife Services, Dan McMurtry

USDA/APHIS/Wildlife Services, Dan McMurtry

The Kerrville Rooter Gate with Missouri Trigger represents the top-of-the-line door 

mechanism for corral-type traps. This unique design allows the door to function 

first as a fall door with a trip-wire trigger and then, after it is triggered, to continue 

acting as a rooter door. What’s more, the door is partitioned into 3 sections so that 

both very large adults and smaller juveniles can open the door and enter the trap. 

For details on construction, see the appendix.

Corral traps, when constructed properly, allow managers to capture large numbers 

of pigs efficiently. A trap like this one, outfitted with a Kerrville Rooter Gate with 

Missouri Trigger, is an outstanding tool for those interested in controlling pig 

populations. 

spots along the fences. Snares generally 

consist of a loop of galvanized aircraft cable 

3/32 inch or 1/8 inch in diameter. The loop 

closes easily but will not open because of a 

sliding lock device. For minimum twisting 

and breakage, a heavy swivel should be used 

on the tie end of the snare to connect it to 

an anchor or drag (Mapston 1999). If a drag 

is to be used, the snare should be fastened 

to something fairly heavy, such as an oak 

limb 6 to 12 feet or more in length. The 

larger the pigs in the area, the larger the 

drag and heavier the cable needed (Barrett 

and Birmingham 1994).

Shooting and Hunting

Aside from trapping, shooting is likely the 

most common technique used to control 

wild pig populations. Shooting may occur 

within the context of recreational hunting, 

or it may be conducted by professionals 

as part of an intentional control program. 

In either case, shooting programs must 

be intense and consistent to reduce wild 

pig populations and associated damage 

effectively. Even then, shooting programs 

usually are most effective when combined 

with other efforts such as trapping.

Sport hunting can be used as a source 

of revenue for landowners and recreation 

for hunters and it may even appear to be an 

attractive control option to some wildlife 

managers. Nevertheless, sport hunting 

usually has little effect on the size of wild 

pig populations (Barret and Stone 1993). 

Sport hunting typically results in the 

removal of mostly adults, and this alone may 

not be enough to reduce the population 

(Bieber and Ruf 2005). In addition, 

hunting pressure can cause pigs to shift 

movements to cover and to develop more 

nocturnal feeding habits, thus resulting 

in a low hunter success rate (Barrett 

and Birmingham 1994). Moreover, sport hunting may actually be 

detrimental in areas where trapping occurs, as the hunting pressure 

may cause pigs to shift away from the area, become more wary, and 

become less susceptible to trapping (Richardson et al. 1997). 

Aerial Shooting

Aerial shooting is another option that can be extremely effective 

in some areas (Hone 1983). In fact, aerial shooting is perhaps 
34

the preferred control technique in landscapes such 

as those in Texas, which features low-growing 

vegetation, gentle topography, and a mild climate. 

In such areas, aerial shooting is so effective that, 

despite the high costs associated with aircraft, it can 

be the most cost-effective option, particularly when 

pig populations are high. As pig populations decline, 

however, aerial shooting produces diminishing returns 

and probably is not cost-effective at low population 

densities (Choquenot et al. 1999). In other areas, 

weather, heavy cover, and rough terrain limit the 

applicability of aerial shooting. 

Sport hunting usually has little 

effect on the size of wild pig 

populations.

Night Shooting

When shooting over bait, the most effective approach 

is to conduct removal operations after dark with night 

vision technology and sound-suppressed weapons; 

before initiating this type of effort, though, be certain 

to check local and state regulations. In many states, 

agencies responsible for wild pig regulations will allow 

night shooting, and sound-suppressed weapons can 

be acquired under special permit. For shooting over 

bait, several days to a few weeks of prebaiting before 

shooting can greatly enhance the success of the 

removal operation. 

Night shooting operations exploit the tendency 

of pigs to become nocturnal in response to human 

pressure and high temperatures, and they allow 

managers to use the cover of darkness. However, 

traditional night shooting approaches — shooting with 

a spotlight and conventional weaponry out of vehicles 

— offer many challenges and simply do not work well 

for wild pigs in most situations. 

Fortunately, though, new technological 

developments have resulted in night vision equipment 

that greatly enhances the success of night shooting 

operations. Technical advances in night vision 

equipment derived from military training are now 

being applied to wild pig control in the United States. 

Two types of equipment are available: systems that 

use near-infrared light and systems that use thermal 

imaging (Pinkston, unpublished report). 

Systems that use near-infrared light have existed 

longer, and many people will recognize them by the 

characteristic greenish images they produce. Early 

versions of this equipment produced images with poor 

resolution, but newer equipment is remarkably clear. 

These devices work by collecting and amplifying visible 

light, including a portion of the infrared light spectrum 

otherwise undetectable to our eyes (Pinkston, 

unpublished report).

Thermal imaging works by capturing the portion 

of the infrared light spectrum that is emitted as heat by 

objects. Hot objects, such as warm-blooded animals, 

emit more light and show up as white when viewed 

in gray scale. Since this equipment works solely by 

capturing infrared energy from an object, no light 

at all is required for the device to function. Warm 

objects stand out against cooler backgrounds and 

become visible. Since the average body temperature 

of wild pigs is 102 ̊F, they are easily detected while 

feeding in surroundings that have cooled to nighttime 

temperatures. Currently, the best thermal devices 

on the commercial market can detect these heat 

sources from more than 0.5 mile away (Pinkston, 

unpublished report). As these technologies improve, 

the devices are becoming smaller and more practical 

for commercial use. However, the price of night vision 

equipment, particularly of the thermal imaging type, is 

currently prohibitive for most landowners. 

Using such equipment for night shooting, it 

may be possible to eliminate entire sounder groups 

feeding at night in open terrain. By using the cover 

of darkness, shooters can approach quite closely to 

groups of wild pigs. Shooters should target adults 

for initial shots and removal as juveniles offer easier 

follow-up shots once shooting commences. When the 

team consists of experienced shooters equipped with 

semi-automatic rifles, such operations can remove all 
35

Using thermal imaging at night, hunters can approach pig groups closely and 

optimize shooting opportunities. 

Rod Pinkston

Rod Pinkston

Thermal imaging equipment enables managers to find wild pigs easily at night.

or most of the individual pigs in the field. 

Although the number of animals that can be 

removed with this technique is impressive, 

research has yet to assess the cost efficacy 

of this approach or its ability to reduce 

pig populations within a larger area. 

Increasingly, though, this is a preferred 

tool for biologists conducting disease 

surveillance, as it allows the sampling of pigs 

across a broad geographic area without the 

investment of time that would be required 

to set up traps in multiple locations.

Judas Pig

The “Judas pig” concept was adapted for 

use in wild pigs from a strategy of using 

radiotelemetry to find and control feral 

goats (Taylor and Katahira 1988). More 

recently, some managers in the United 

States have had success with the Judas 

technique with pigs (Wilcox et al. 2004, 

McCann and Garcelon 2008). In essence, 

the technique relies on tracking radiotagged pigs to locate larger social groups, 

which can then be removed using a variety 

of methods. This technique has been used 

with some success in Australia (McIlroy 

and Gifford 1997, Australasian Wildlife 

Management Society 2006) and here in the 

United States (Wilcox et al. 2004, McCann 

and Garcelon 2008). 

Managers have used a variety of 

techniques to capture individuals for radio 

tagging, including capture from helicopters 

and the use of dogs (Australasian Wildlife 

Management Society 2006), but cage traps 

are far and away the most common capture 

tool employed. Indeed, the cost efficiency 

of the Judas pig strategy is greatest when it 

can be integrated into an existing trapping 

program. Once captured, individuals are 

equipped with radio transmitting equipment 

(Braun 2005), visibly marked with paint 

or ear tags, and released. Subsequently, the tagged individuals will 

reintegrate with social groups and enable managers to locate large 

pig congregations. 

Uncertainty remains about which individuals make the best 

subjects to serve as the Judas pig. Theoretically, because of their 

role as a social matron, adult females should be the best choice. 

However, ongoing research has failed to conclusively confirm this 

prediction, and others have actually suggested that adult males may 

be better suited to serve as the betraying individual (Australasian 

Wildlife Management Society 2006). In reality, the research 

conducted thus far was not large or comprehensive enough to 
36

The Judas pig. Some have speculated that radio-tagging a captured pig and 

releasing it can be a useful tool in tracking larger groups to target for control. 

However, this is a relatively new strategy, and more information is needed to 

understand when and where the Judas Pig technique would be effective.

Chris Jaworowski

Chris Jaworowski

address this issue fully; more research is needed to help identify 

which type of pig (adult versus juvenile, male versus female) is most 

effective to radio tag and betray its cohorts. 

Managers can use the knowledge of pig group locations in 

many ways to facilitate control. Although little research has been 

conducted in the United States regarding the Judas pig concept, 

Australian researchers have demonstrated its effectiveness in 

many ways. Managers in other countries have used knowledge 

of pig group locations to refine the placement of toxicant baits, 

thereby increasing effectiveness and decreasing cost (McIlroy and 

Gifford 1997). In addition, aerial shooting can be substantially more 

effective using the Judas pig technique 

(Australasian Wildlife Management Society 

2006), and anecdotal reports indicate 

similar increases in effectiveness for night 

shooting programs. 

On the other hand, McCann and 

Garcelon (2008) evaluated the Judas 

pig technique to reduce pig populations 

on Pinnacle National Monument and 

concluded by being skeptical about 

the value of the technique. In any 

case, McCann and Garcelon (2008) 

recommended strongly that managers 

employing the Judas pig technique sterilize 

animals before releasing them back into 

the population, as they spent significant 

time removing offspring of their Judas pig 

subjects from the population. 

Hunting with Dogs

Hunting with dogs can be effective at 

reducing wild pig populations in local areas 

and has been successfully used as part of 

larger control programs (Choquenot et al. 

1996). In some cases, though, hunting with 

dogs simply causes pigs to move into adjacent 

areas. This shift in location can protect 

small, isolated, sensitive areas but may simply 

relocate the problem rather than alleviate 

it (Barrett and Birmingham 1994). On the 

other hand, some have speculated that 

harassment, such as that created by hunting 

with dogs, can cause home range shifts away 

from particular areas of concern and thus is 

a viable management technique (Engeman et 

al. 2006, Hayes 2007, Gaston 2008). 

Many factors must be considered if 

hunting with dogs is to be successful. The 

experience of the dogs and hunters are 

integral elements in the success of this 

method. Poorly trained dogs, unseasoned 

hunters, hot weather, injuries, and the cost 

of good dogs, their training, and their care 
37

can all be impediments to the success of this method 

(Mapston 1999). In many areas of the South, hunters 

often do not actually kill pigs during the hunt, but 

rather use dogs to help capture individual pigs, which 

are transported to a holding pen or another area. 

These practices are particularly troublesome as such 

transport can spread diseases and compromise broader 

control efforts. Those interested in using dog-assisted 

hunting as part of a management strategy should 

review the detailed account by Mayer et al. (2009). 

Toxicants

No chemical toxicant is registered for use on wild pigs 

in the United States. However, the motivation to 

identify and register a toxicant for wild pigs is strong 

because it can be a powerful and cost-effective tool 

for controlling or eliminating animal populations. For 

example, Coblentz and Baber (1987) reported that 

poisoning was 11 times cheaper than shooting and 80 

times cheaper than trapping during a pig eradication 

program in Ecuador. Thus, researchers are working 

to identify a toxicant that can humanely kill wild pigs 

while having a benign effect on nontarget animals and 

the larger environment. 

No chemical toxicant is registered 

for use on wild pigs in the United 

States.

Toxicants are an effective and important tool for 

pig control in some countries, Australia and New 

Zealand in particular. Warfarin, an anticoagulant 

widely used as a rodent toxicant, has been used to 

control and nearly eliminate wild pig populations in 

Australia (Saunders et al. 1990). However, because 

of secondary poisoning and other environmental 

concerns, warfarin is not currently an option in the 

United States. 

More recently, researchers in Australia have 

developed the product PIGOUT®, a bait containing 

the compound 1080, to achieve population reduction 

of at least 73% (Cowled et al. 2006a). PIGOUT 

is designed to attract wild pigs and not other 

native wildlife species in Australia. During trials in 

Australia, which has no native midsized generalist 

mammals and thus is an environment where speciesspecific baits are viable, the product has shown 

great promise (Cowled et al. 2006b). Unfortunately, 

research in Texas demonstrated that many nontarget 

species (mostly midsized generalist mammals) would 

be adversely impacted by toxicant-laced PIGOUT 

baits in North American ecosystems, and thus it is 

currently not a viable alternative in the United States 

(Campbell et al. 2006). 

Although PIGOUT has been shown to be effective 

in controlling pig populations in Australia without 

adversely affecting nontarget animals, some problems 

do exist with its use. Most notably, pigs are relatively 

insensitive to 1080, some perceive the toxin to cause 

an inhumane death, it can remain toxic in the carcass 

and environment, and there is no antidote if humans 

are accidentally exposed to the toxin. In search for 

answers to these problems with 1080, an Australian, 

research team has identified another toxin, sodium 

nitrite, that reportedly causes a quick and humane 

death, is palatable yet toxic to wild pigs, is cheap and 

accessible, is degradable in the environment, and 

reduces risk to the operator as it has an effective 

antidote (Invasive Animals CRC 2008). Sodium nitrite 

already has undergone some preliminary pen trials, 

which are promising, and field trials are now under way 

in the form of a commercial formulation named HOGGONE® (Cowled et al. 2008). 

For any toxicant to become a viable technique in 

the United States, researchers must develop either 

toxicants or delivery systems that are species specific. 

Of these, development of a species-specific delivery 

system is most likely. Researchers are currently 

working to evaluate 2 delivery systems that were 

designed to deliver baits (that could be laced with 

either toxicants or contraceptive agents) to wild pigs 

while restricting access of other species. Researchers 

in the United Kingdom have developed the Boar 

Operated System (BOS), which consists of a bait 
38

platform and sliding cover (Personal Communication, 

Giovanna Massei, United Kingdom Central Science 

Laboratory). Australian researchers have likewise 

developed a device to distribute baits to wild pigs but 

not to other species, the Boar Buffet® (Lapidge et al. 

2009). Both of these systems exploit pigs’ behavioral 

tendencies (feeding behavior) and physical traits (size 

and strength) to provide adult pigs access to bait, 

while limiting access to most other species. Some 

species like black bears, though, presumably could 

defeat the device. Although these devices show 

promise as a management tool, researchers have much 

work yet to do in evaluating their effectiveness and 

species specificity in various ecosystems.

NONLETHAL TECHNIQUES

Fencing

Excluding wild pigs with wire mesh fencing, electric 

fencing, or a combination of both can be an effective 

control measure. While few fence designs completely 

exclude pigs from an area, many fences can restrict 

pig movements. Though fences may restrict pig 

movements, they can be expensive to install and 

managers must ultimately consider the value of the 

commodity and cost of the fence before committing 

to this avenue of control (Conover 2002). Sturdy 

wire mesh fencing, particularly with the addition of 

an electrified wire about 6 to 8 inches off the ground, 

seems to be the most effective fence design to exclude 

wild pigs (Hone and Atkinson 1983). 

Nonelectric fences should be of net wire or 

diamond mesh construction with a maximum of 6-inch 

spacing (Littauer 1993). To be effective in sheep- or 

goat-rearing areas, spacing should be no more than 

4 inches to prevent livestock from sticking their 

heads through the fence. Fences should be at least 

36 inches high, and the bottom wire should be tightly 

stretched on the ground surface or buried (Mapston 

1999). While fencing can be an effective management 

technique, installing poorly designed or improperly 

constructed fences around areas in hopes of reducing 

Research has demonstrated that electric fences can restrict the 

movement of wild pigs and thus have the potential to reduce 

damage. More extensive field testing is yet needed, though, 

to fully evaluate the practicality and cost effectiveness of this 

management tool.

USDA/APHIS/Wildlife Services, Tyler Campbell

pig damage can simply add the expense of frequent 

fence repair to the cost of damage (Beach 1993). 

The addition of one or more electrified wires 

into existing net wire or other fences is possible and 

will reduce the likelihood of wild pigs penetrating 

the fence (Hone and Atkinson 1983, Littauer 1993). 

If installing new fences, though, simple electric 

fences with just a few electrified wires represent an 

attractive option because they are cheaper and easier 

to install than traditional net wire fencing. Reidy 

et al. (2008) reported that portable electric fences 

can significantly restrict, although not completely 

eliminate, the movement of pigs into a protected area. 

They found that simple electric fences consisting of 

only 2 electrified wires, one at 8 inches and one at 18 

inches above the ground, were as effective as 3-wire 

designs and reduced daily intrusions of pigs into an 

area by 50%. Though initially cheap and easy to install, 

electric fences with low wires can require substantial 
39

maintenance to prevent growing vegetation from 

contacting and grounding the electric wires.

Harassment

Human activity can have a substantive impact on 

pig behavior, movement, and survival. Although 

probably not an effective strategy on a large scale, 

harassment of pigs through hunting and pursuit 

may be a very effective technique for reducing pig 

populations and damage on small areas and for discrete 

resources. Engeman et al. (2003, 2006) reported 

that recreational hunting, even when few animals 

are actually harvested, reduced damage to sensitive 

wetland sites in Florida. Many have reported that pigs 

reduce or shift home ranges in response to hunting, 

trapping, and other harassment, and even that juvenile 

survival is reduced in the face of such pressure (Hayes 

2007, Gaston 2008). On the other hand, Sodeikat and 

Pohlmeyer (2003) found that pigs may temporarily flee 

an area in the face of intense hunting, but they often 

return to their original home range.

Human activity can have a 

substantive impact on pig 

behavior, movement, and 

survival.

Harassment, particularly through aggressive 

hunting, may be a viable technique for some managers, 

particularly those interested in protecting specific 

resources for a defined time period. On a larger 

scale, though, harassment has limited value and likely 

just shifts pig problems from one area to another. 

Some have even speculated that harassment leads 

to a greater risk of disease transmission (Sodeikat 

and Pohlmeyer 2003) within the larger wild pig 

population.

Vaccination

Some studies have been conducted on the feasibility 

of vaccinating wild pig populations as a means of 

protecting domestic stock and other wildlife. One 

study into the possibility of a brucellosis vaccination 

in the southeastern United States had positive results 

(Elzer 1999). By delivering a brucellosis vaccine orally 

in a mixture of corn syrup and pecan shells poured 

over corn, the researchers managed to vaccinate 

wild pigs. This method relies on the use of a viscous 

solution (corn syrup) to contain the vaccine combined 

with an oral scarification agent (pecan shells) to 

allow the vaccine direct access to tissues (Elzer 

1999). Vaccination may become a nonlethal method 

to control disease spread in wild pig populations as 

further research improves upon economic feasibility 

and refines delivery techniques. However, this method 

is not currently viable for widespread use, nor does it 

alleviate myriad other problems associated with wild 

pig presence.

Contraception

Interest is strong in developing contraceptives 

capable of limiting wild pig populations over 

time. Some studies have shown injections of 

gonadotropin-releasing hormone (GnRH) to be 

effective in captive wild pigs (Killian et al. 2003). 

Results of GnRH injections included reduced ovary 

and testis weight, reduced levels of testosterone 

and progesterone, and reduced pregnancy rates in 

treated pigs when compared to controls (Killian et 

al. 2003). Unfortunately, these compounds are still 

under investigation and are currently available only 

in injection form, an unrealistic method for field 

application. Questions remain as to the duration of 

infertility, the reversibility of the effects, and whether 

an oral form of the vaccine—more conducive to wild 

pig management—can be developed. 

One contraceptive vaccine being examined for 

approval and registration is GonaConTM. GonaCon is 

a single-shot, multiyear, GnRH immunocontraceptive 

vaccine that decreases sexual activity and prevents 

animals from entering a reproductive state through 

manipulation of hormones. Studies have shown that 

GonaCon Immunocontraceptive Vaccine suppresses 

reproduction in treated animals of both sexes and 
40

keeps females infertile without boosting. However, 

this infertility is not permanent (lasting 1 to 4 years) 

and reverses on its own over time. Multiple injections 

increase the longevity of the vaccine (Miller et al. 

2004). The GnRH vaccine has been shown to induce 

contraception in several mammalian species, including 

ground squirrels, domestic cats, domestic and feral 

pigs, and deer (Fagerstone et al. 2008). GonaCon 

is currently under review for possible approval as 

a restricted-use vaccine. For now, there are no 

contraceptives available for wild pigs. 
41

SUMMARY

Wild pigs are and will continue to be a challenging problem for wildlife 

managers, landowners, farmers, conservationists, and others. Despite 

ongoing control programs, wild pigs have increased both their range and 

population size. Because of this growth, wildlife managers will increasingly 

be involved in dealing with problems caused by wild pigs traditionally, 

as well as emerging problems such as landscaping damage in suburban 

areas. Certainly, wild pigs promise to be one of the more significant and 

challenging vertebrate wildlife pests for the foreseeable future. In response, 

wildlife professionals have dedicated significant effort to better manage 

problems caused by wild pigs, as more and more research, conferences, 

symposia, and articles in the profession are focused on pig-related issues 

(Ditchkoff and West 2007).

As Conover (2002) notes, human-wildlife conflicts are complex, and 

a myriad of ecological, biological, social, legal, and economic factors are 

involved. As a result, few wildlife problems have single or simple solutions. 

Instead, the most successful wildlife damage management strategies employ 

a diversity of tactics in a comprehensive, integrated approach. Without 

doubt, this principle is applicable to wild pigs. An integrated approach 

to wild pig management — where managers use a variety of techniques 

to remove pigs and prevent damage — is most effective (Choquenot et 

al. 1996, Mapston 1999). Wild pigs may quickly learn to avoid single 

control techniques but often have difficulty avoiding multiple techniques 

implemented in combination (Richardson et al. 1997). Nevertheless, it is 

The most successful 

wildlife damage 

management 

strategies employ a 

diversity of tactics 

in a comprehensive, 

integrated approach.

Eddie Parham
42

unlikely that individual landowners will be able to 

reduce pig populations, regardless of the intensity 

of control efforts on their individual properties. If a 

population reduction is desired, it almost certainly 

will require efforts across a geographic area larger 

than that of the average private landholding. In such 

cases, landowners may need to create partnerships 

among neighbors to jointly pursue the reduction of 

pig populations. 

Successful management strategies will certainly 

depend upon persistent, adaptive, and integrated 

management programs that incorporate sound 

biological and ecological information (Campbell 

and Long 2009). These strategies alone, though, 

are insufficient. Because wild pigs reside principally 

on private lands over much of their range, astute 

wildlife managers will understand that stakeholder 

involvement and education are paramount to managing 

wild pig problems. As West (2009) articulates, the 

problems associated with wild pigs can be defined only 

within the context of human perceptions, experiences, 

and values. As such, an integrated management 

approach, in addition to addressing the biological and 

ecological aspects of wild pigs, will seek to engage 

stakeholders via comprehensive education and 

communication programs. We hope this guide can be 

a valuable tool in that crucial task.

Wild pigs can cause damage in a variety of areas, not just in 

agricultural fields. Here, pigs have caused significant damage 

to residential lawns in Texas. As the range and abundance of 

wild pigs increase, these kinds of problems will become more 

common. 

Billy Higginbotham
43

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APPENDIX

Detailed construction plans for a cage trap employing a Kerrville Rooter Gate with Missouri Trigger
52
53
54

AUTHORS

BEN C. WEST 

Ben earned degrees in natural resources and wildlife biology from the University of Tennessee-Martin (B.S.), 

Virginia Tech (M.S.), and Utah State University (Ph.D.). Since joining the faculty at Mississippi State University, 

Ben has been involved in a number of extension/outreach projects involving wildlife damage management. Now, as 

outreach coordinator for the Berryman Institute, Ben coordinates training and produces educational products for 

wildlife damage professionals nationwide.

ANDREA “ANDI” L. COOPER 

Andi is a native Mississippian who attended Mississippi State University where she majored in Wildlife and 

Fisheries Science, Wildlife Science option. She received her Bachelor’s in 2004 and master’s degree in 2007. 

She currently holds a position with Ducks Unlimited’s Southern Regional Office in Ridgeland, MS as their 

Communications Biologist and is responsible for the communications needs of the 15 states in the Southern Region.

JAMES “JIM” B. ARMSTRONG 

Jim is a professor and coordinator for the Extension Forestry, Wildlife and Natural Resources Program for the 

Alabama Cooperative Extension System and Auburn University, School of Forestry and Wildlife Sciences. He 

has served as chair-elect/chair/past-chair of the Wildlife Damage Working Group of The Wildlife Society and has 

been a TWS-certified wildlife biologist since 1987. Jim’s professional interests revolve around all aspects of wildlife 

damage management and human dimensions of wildlife management. 
55

Support for this project was provided by
Human-Wildlife 

Interactions Monograph 1