Animal and Plant Health Inspection Service

Program Aid No. 2174

FERAL SWINE:

Impacts to 

Native Wildlife

What Can I Do?

Feral swine cause problems by damaging native 

ecosystems, preying on or competing with native 

wildlife, and spreading diseases.

• If you live in a State with no or low 

populations of feral swine, report any 

sightings, sign, or damage to the wildlife or 

agriculture officials in your State.

• Do not relocate feral swine to new areas or 

transport them to other States.

• Share the knowledge, spread the word, and 

discourage the transportation and spread of 

feral swine. 

What Is Being Done? 

The U.S. Department of Agriculture’s (USDA) 

Animal and Plant Health Inspection Service 

(APHIS) has coordinated and begun a national 

effort to manage the extensive damage caused 

by expanding invasive feral swine populations by 

working closely with partners at the Federal, State, 

and local levels. 

Want To Learn More?

Call the APHIS Wildlife Services program in your 

State at 1-866-4-USDA-WS or go to www.aphis.

usda.gov/wildlife-damage/stopferalswine to 

learn more about the problems caused by this 

invasive animal, as well as to seek advice and 

assistance in dealing with feral swine.

Photo credits: Images courtesy of USDA-APHIS Wildlife Services and 

U.S. Fish and Wildlife Service. 

USDA is an equal opportunity provider, employer, and lender.

Program Aid No. 2195d Issued October 2016

Animal and Plant Health Inspection Service

Large sounder wallowing, damaging habitat
What Are Feral Swine 

and Where Are They 

Found? 

Feral swine were first introduced to the United 

States by Spanish explorers in the 1500s. Since then, 

natural breeding, new introductions, and relocation 

by humans have caused populations to rapidly 

expand. Feral swine can thrive in almost any habitat, 

mature at 6 to 8 months of age, and a single sow can 

have up to 2 litters of 4 to 12 piglets a year, making 

them a prime example of an invasive species. Growing 

feral swine populations are encroaching on many 

important wildlife habitats, causing significant damages 

to these ecosystems. Feral swine also damage the 

quality of lands for ranching, recreation, and other 

uses. Feral swine populations impact important 

habitats and ecosystems, which further jeopardizes 

threatened, endangered, and already vulnerable 

species. Feral swine also live in habitats of importance 

to deer, turkeys, upland birds, and other valuable game 

species; they pose economic risks to businesses that 

depend on these game species to succeed. 

How Do Feral Swine 

Impact Native Wildlife 

and Plants? 

Feral swine are one of the world’s worst invasive 

species. It has been estimated that feral swine have 

played a role in the decline of nearly 300 native plants 

and animals in the United States alone. Over 250 of 

these species are threatened or endangered, while 

others are valuable game animals or important native 

forage plants. Feral swine impact native species and 

ecosystems in a 

variety of ways—

from direct predation 

or competition to 

altering ecosystems 

and destroying 

habitats through 

their destructive 

foraging, trampling, 

and wallowing 

behaviors.

DIRECT IMPACTS

Feral swine are opportunistic omnivores that prey on 

the nests, eggs, and young of native wildlife such as 

sea turtles, prairie chickens, wild turkeys, alligators, 

and upland game birds. They also prey on both the 

young and adults of small vertebrate species such as 

rodents, amphibians, and reptiles like the endangered 

dunes sagebrush lizard. They root out and eat 

amphibians and invertebrates from ground cover, 

threatening species such as the flatwoods salamander. 

They tear up grasses, shrubs, and seedlings, killing 

sensitive plants such as Mead’s milkweed. Feral 

swine compete with native wildlife for many key 

resources. Their keen sense of smell, tenacious 

feeding behaviors, and ability to digest a variety of 

foods makes them serious competitors for nutritional 

resources. They consume the fruits, nuts, and seeds 

of trees, thereby competing with deer, turkeys, black 

bears, and small mammals such as squirrels. Feral 

swine are aggressive animals and will actively chase 

off other species. Their generally disruptive behavior, 

particularly around feeding or wallowing areas, will 

disturb and scatter other animals. For example, the 

endangered Houston toad will avoid breeding in 

ponds the feral swine use for wallowing. 

INDIRECT 

IMPACTS

Feral swine 

are ecosystem 

engineers, which 

means they can 

change their 

environment by 

impacting the 

vegetation and 

soils throughout 

their range, 

changing plant 

distribution in 

Feral Swine 

Populations by County, 2015

grasslands and forests, and destroying habitats 

for rare species such as Hine’s emerald dragonfly. 

Consuming nuts and seeds, along with rooting 

and rubbing behaviors, can impact forest growth, 

particularly in oak forests. Feral swine aid in 

spreading invasive plant species, such as strawberry 

guava, by disturbing the native plants and 

transporting invasive weed seeds. They alter runoff 

and water quality in wetland environments, through 

rooting and wallowing, which impacts fish species 

such as the Oskaloosa darter. Feral swine carry over 

30 pathogens and 40 parasites, many of which can 

infect wildlife. 

FAR-REACHING IMPACTS

Feral swine 

eat mostly 

vegetation, but 

recent research 

shows they will 

prey on native 

wildlife as well. 

Feral swine have 

been known to 

consume the 

eggs of groundnesting birds, 

reptiles, or 

amphibians; the 

young of large 

mammals such 

as deer; and both the young and adults of small 

mammals, reptiles, and amphibians.

Habitat change, through their wallowing, rooting, 

and feeding, is the most widespread and harmful 

impact of feral swine to native wildlife. Feral swine 

alter wetland and riparian habitats, pollute water, 

change vegetation composition and distribution, 

and displace native wildlife across the United States. 

Feral swine rooting protected sea turtle nest to eat eggs 

The feral swine distribution map was prepared from data 

independently compiled by State, Federal, and Territorial fish 

and wildlife management agencies, agriculture agencies, 

and universities of the United States in cooperation with the 

Southeastern Cooperative Wildlife Disease Study, College of 

Veterinary Medicine, University of Georgia. Support for this project 

was through Cooperative Agreement Number 15-9100-1407, 

Veterinary Services, Animal and Plant Health Inspection Service, 

U.S. Department of Agriculture.

Feral swine preying on ground-nesting bird eggs