Sus scrofa
Domestic Pig
Geographic Range
Pioneering pigs, which emigrated from Europe to the Western Hemisphere in the
fifteenth and sixteenth centuries quickly, made themselves at home. The woodlands,
hills, swamps, marshes, lowlands, and forests. Confined to the sty, ranged the woods and
grazing lands, or escaped to lead a feral existence Sus scrofa can survive in all conditions
Found Palearctic, Oceanic Islands, Nearctic, Oriental, Ethiopian, Neotropical, Australian;
making Sus scrofa the largest ranging Suidae. (Towe 1950, Martin 2001, Hruby 2003)
Physical Description
The Suidae has 5 genera and 16 species. Sus scrofa, ordinal name Artiodactyla
meaning, and “even-digited ones”. The fact that artiodactylas are even toed ungulates
distinguishes them from the perissodactyls, which are odd-toed ungulates. There are
generally two or four digits and the limbs are paraxonic, with the plane of symmetry
passing between the third and fourth digits of each foot. Sus scrofa has a four pedal
digits. Most living artiodactyla are herbivorous, but some of the more generalized forms
(hogs) are omnivorous. Suids have short legs; heavyset bodies; thick skin with short,
coarse pelage; small eyes; a relatively large head; and a prominent snout truncated at the
end with a round, cartilaginous disk. Several layers of muscles are associated with the
snout, which is used in rooting for food. Several species have large facial warts, most
prominent males. The sense of smell is its biggest advantage. Lacking in good eyesight
due to eyes being located on the sides of the head. Ears are varying from small and erect
to erect and low and flapping. The maximum body mass range is approximately 200 kg
in the wild boar. Upper incisors present; seven upper cheek teeth on each side; cheek
teeth with many rounded cusps; orbit not surrounded by complete, circular, bony ring.
Dental formula 3/3 1/1 4/4 3/3 = 44; 1/3 1/1 3/2 3/3 =34; 2/3 1/1 2/2 3/3 = 34; upper
canines curve either outward, upward, or both. (Swine, hogs, pigs) With simple
stomachs, bunodont cheekteeth, and large, ever-growing canines—the upper pair curving
up and outward to form tusks. (Sus scrofa).
Food Habits
The large head and mobile snout are used to root for food. Sus scrofa is omnivorous and
sometimes indiscriminant diet. Diet includes shrubs, roots, acorns, nuts, bulbs, tubers,
weeds, bird eggs, frogs, snakes, insects, mice, roots, tubers, small weakened or vulnerable
animals, carrion, and even manure. Occasionally cannibalism occurs. Diet tends to vary
with season, climate and availability. Foraging occurs both during the day and night, but
is most intense at night, especially during the summer. Wild hogs have one stomach and
do not chew cud. Suids are gregarious and often forage in-groups. The wide array of
food sources has allowed Sus scrofa be survive in a wide array of environments from
deserts to mountainous terrain.
Reproduction
Suids are sexually mature by 18 months of age; although male may not have
access to females until they are 4 years old. Females have an estrous of about 21 days and
are receptive for 3 days. Gestation is 115 days for domestic pigs. The litter size ranges
from 1to12(peak litter size at 2-3years). Mating occurs year round in tropical climates
and in the spring in temperate climates. On average only half of litter will survive to
maturity in the wild many fall to disease or predators. The piglets are weaned in three to
four months, and may leave the mother prior to the birth of the next litter. The most
aggressive of the males will secure as many as eight sows during one mating season.
~ Predation
Humans are the major predators of this species. Carnivores such as black bears
and mountain lions are capable of taking down young adults. Piglets may be preyed
upon my bobcats, foxes, and coyotes.
~ Behavior
Foraging occurs both during the day and night, but is most intense at night,
especially during the summer. Near-term females leave the group to give birth and rejoin
shortly after as mothers that are extremely protective of their young. Mating season
brings about violent times for males in search of the prize sow. Sharp tusks are used to
fend off other males and a thick tissue is developed around the front of the belly in
defense. Wild hogs are sometimes found in large herds of up to 100. Typical herds
number 20 individuals composed of two families of females and their litters. Males leave
the group at sexual maturity and live on their own.
Pigs are ideal for domestication because of their diverse feeding habits.
Pigs scavenged on discarded food remains in association with early human settlements,
before they were eventually confined. And the piglets are easily tamed and acclimated to
humans.
~ Habitat
Biomes: temperate forest and rainforest, temperate grassland
Due to domestication feral invasive Sus scrofa have adapted to a wide variety of
habitats. Typically, wild hogs are found in moist forests and shrublands, especially oak
forests and areas where reeds are abundant. Snowfall levels limit the range of the pigs by
making travel and finding food relatively difficult. Severe temperature changes cause
difficulties in adaptation. Wallowing in mud or water help maintain a comfortable
temperature while also protecting against sunburn and insect bites.
~ Economic Importance for Humans
Positive
Pigs play the most important role serving as breakfast, lunch or dinner for
humans. In France, pigs have been used to find truffles(underground fungi) used in
French cuisine. In England the sense of smell was used for hunting. In ancient Egypt
they were used for the planting of seeds in the hoof prints. Pigs are an important game
species in the Gulf states as well as throughout the United States. Management of the
hogs is performed by moving nuisance animals to public hunting areas. In George on
private lands wild pigs are hunted year round for food and sport. The promise of
xenotransplantation is now a reality female pigs have been cloned to have an enzyme that
allows for pig to human organ transplantation. Pigs have served as food and as sacrificial
animals in many cultures. Pigs have also contributed to the entertainment business such
as starring roles in movies such as Babe and Babe in the Big City, and the world famous
Charlotte's Web.
Negative
Wild pigs have a negative impact on the environment by disturbing the soil and
natural vegetation by rooting which leads to the shift in plant community structures. Pigs
also compete with local native animals for food. Sus scrofa carries transmissible parasitic
infections to humans such as trichinosis, cysticercosis, and brudellosis caused by eating
undercooked meat. Wild hogs are also reservoirs for several serious diseases. They carry
pseudorabies, which is fatal in panthers, swine brucellosis, which can be fatal in people,
African swine fever, cysticercosis, and trichinosis.
~ Conservation
Sus scrofa has no special status as far as IUCN, U.S. ESA, or CITES. Overall
pigs are not threatened by extinction, though some domesticated breeds have disappeared
in recent years. Pigs are ever increasingly becoming more popular as indoor house pets.
~History
Along with the sheep, goats, cattle, and horses introduce by Columbus came eight
porters, who crossed the Atlantic with the Admiral on his second voyage in 1493, and
became the reputed progenitors of all the hogs that populated the Spanish Indies. In
Espanola, Jamaica, and Cuba, they soon ran wild through the jungles and canebrakes.
Soldiers hunting rebellious Indian neophytes and escaped Negro slaves were often
attacked by these belligerent pigs, especially when the animals were cornered. By 1850,
the Middle West contained 3.7 times as many swine as the Eastern states. The
Napoleonic wars in Europe made the price of corn along the Atlantic seaboard so high
that much of it was shipped abroad, causing a meat shortage so high that much of it was
shipped abroad, causing a meat shortage that could be relieved only by the cattle, sheep,
and swine of the Midwestern drover.
They may have been domesticated first in the Middle East and western Asia, about 7000
to 8000 years ago. Historically, groups of domesticated pigs were allowed to roam loose,
watched by a swineherd, or were housed in a “pigsty” or pen. Numerous breeds of pigs
are now recognized. More than 100 breeds of domestic pigs are recognized throughout
the world today.
~Swine Industry Developments
There are many similarities of the swine and the poultry industry, although the
swine industry has provided the market’s demand for pork with independent producers
some forty years longer than producers in poultry have have. However, we can
distinguish clear parallels between historical phases in the two industries. Prior to the last
decade, essentially all pork was owned and produced independently by farmers who took
their pigs to auction. Corporate swine farms are operating in a number of states now, and
the small independent farmer is finding it increasingly difficult to find a market. The
tremendous production by mega-farms also drives the price of pork down over time,
contributing to the demise of many independent farms. The poultry industry development
in which the processors have complete control over all aspects of the production process
from embryo to the market shelf. The swine industry has not yet entered this phase, as
processors have not established absolute control over producers. As more independent
producers are eliminated from the business and the majority of production is done under
contractors, difficulties in production will multiply. Pork producers will be situated
similarly to poultry growers both economically and socially. Sustainable agriculture may
offer smaller, independent hog farmers hope for finding an alternative to large-scale
industrial production.
Hogs constitute an important sector of the Midwestern agricultural economy.
What is more important, hogs are the economic backbone of many diversified family
farms. Hogs provide a value-added market for crops, stabilized farm income, recycled
nutrients, and scavenged wastes. Hogs and other livestock provide year-round
employment for farm family members who are otherwise underemployment in
specialized cropping systems. Hogs on farms provide a classic example of synergistic
productivity. They are capable of adding far more to farming systems than in apparent
from superficial economic examinations of hog enterprises such as the one descried
below.
The production environment in large-scale operations is controlled through
utilization of buildings and equipment that require large capital investments but greatly
reduce labor requirements. Production technologies associated with large-scale, contract
production also change the nature of management. Mass production technologies that
standardize genetic selection, breeding, feeding, herd health, and marketing functions
transfer most of the management function from on-site hog producers to corporate
production supervisors who travel among production units and to production mangers at
corporate
Headquarters. Large-scale, specialized hog production replaces people with capital
intensive, mass-production technologies and centralized management.
For family farms, total returns over direct production costs are available for local retail
spending. For most corporate operations, only those costs paid in local wages and
salaries are available for retail spending. Using average income figures tends to
underestimates their impacts on employment in manufacturing and wholesaling.
Successful owner-operated family farms tend to be smaller and, in general, employ more
people per acre or per dollar of output than do corporate enterprises. More people in the
local community tend to generate more local retail spending.
~References
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(November/December 2002).
Feldhamer, George A.; Lee C. Drickamer, Stephen H. Vessey, and Joseph F. Merritt,
Mammalogy: Adaptation, Diversity, and Ecology Second Edition, McGraw-Hill
2004, 1999 P.319-454.
Georgia Wildlife Web. "The Georgia Museum of Natural History and Georgia
Department of Natural Resources".
http://museum.nhm.uga.edu/gawildlife/mammals/artiodactyla/suidae/sscrofa.html.
June 1 2000.
Hruby, Jennifer. “Species Account for Sus Scrofa”.
http://animaldiversity.ummz.umich.edu/accounts/sus/s._scrofa$narrative.html.
November, 16, 2003.
Kaebnick, Gregory E. The Hastings Center Report "The Cloned Pigs and the "Reality"
of Xenotransplantation." v. 32 no. 2 (March/April 2002).
Kurta, Allen , Mammals of the Great Lakes Region, The University of Michigan Press,
1995 P. 320.
Martin, Robert E.; Ronald H. Pine, Anthony F. DeBlase, A Manual of Mammalogy,
Mcgraw-Hill, New York, NY 2001 P. 172-175.
Stuart, Poss G. Non-Indigenous Species in the Gulf of Mexico Ecosystem. "Sus scrofa".
www.gsmfc.org/nis/nis/sus_scrofa.html . August 30, 1999.
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Published by State University of New York Press, Albany 1998 P. 6-165.
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Reference written by Margaret Haas, Biol 378: Edited by Chris Yahnke.
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