European Wild Hog
Don Linzey & Christy Brecht
Wytheville Community College
Wytheville, Virginia 24382
Species Description
- Adult total length:
4 1/2 - 6 ft. (132 - 182 cm)
- Tail:
6 - 12 in. (15 - 30 cm)
- Hind foot:
2 1/2 - 3 ft. (75 - 90 cm)
- Weight:
77 - 440 lbs. (35 - 200 kg)
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Physical Characteristics:
The body of the European wild hog, a non-native (exotic) member
of the park's fauna, is built somewhat like that of a bison,
being higher and heavier in the shoulder region. It is covered
with thin, coarse hair. Hogs are usually black, but the tips of
the guard hairs are silvery-gray or brown. A mane of long bristles
may develop down the back. The upper tusks are distinctive in that
they curve upward as they grow. The average weight of 181 adult
males taken in the park was 197 pounds (90 kg), while the average
weight of 12 adult females was 147 pounds (67 kg) (
Duncan, 1974).
Phylogeny
Geographic distribution
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Range Maps
Great Smokies |
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Great Smoky Mountains National Park:
It is not known exactly how or when the European wild hog came to the
park. Thirteen young boars, weighing 60 to 75 lbs. apiece, first
arrived in Murphy, North Carolina (approximately 40 mi. south of the
park), in April 1912, destined for a game preserve on Hooper Bald, where
they were released (Stegeman, 1938). It is believed
that the animals had been purchased through an agent in Berlin, who
said they came from Russia. About 1920, an estimated 100 boars escaped
from the preserve. As they dispersed, they hybridized freely with feral
domestic pigs. Kellogg (1939) stated: "So far as
known to Arthur Stupka, park naturalist, no wild boars have come into
the Great Smoky Mountains National Park. He believes that the Little
Tennessee River, which separates the park from the Cherokee National
Forest, may constitute a real barrier against the northward spread of
this introduced species."
Unfortunately, the hogs managed to cross the river and made their way
into the park. According to Jones (1957), it is
believed that they entered the southwestern quadrant of the park near
Calderwood in the late 1940s. However, the park mammal collection
contains a specimen taken along Hesse Creek north of Cades Cove on
January 15, 1945. Since the 1940s, the invasion has steadily spread
from west to east (Fox and Pelton, 1977), averaging
approximately 2.75 km per year (Singer, 1981).
Hog depredations were first noted on Gregory Bald and along the state
line in 1958. In 1959, it was found that these animals were concentrated
in the area between Cades Cove and Fontana Lake. Trapping began during
August 1959, when an estimated 500 hogs were in the park. The estimated
population increased to approximately 1500 in 1980 (
Singer and Ackerman, 1981). Hog densities in 1979 in the northern
hardwood forests in the western half of the park were estimated to be
79 animals per square kilometer from April to July (
Singer, 1981). During the period 1959-December, 2001, 9,720 hogs
were removed from the park (Stiver, pers. comm.. Oct. 2001).
Hogs range throughout the park.
Habitat
Wild hogs inhabit a variety of habitats in the park including forests and grass balds.
They are found at low densities at all elevations throughout the park.
Natural History
- Reproduction
Mature males are physiologically capable of breeding year-round. Females are
capable of farrowing during any month but exhibited peaks in breeding and
farrowing. Farrowing in the park occurs year-round with peaks in late fall-
early winter and late spring-early summer. Most females farrow once a year,
but when food is abundant, some sows may give birth to two litters within a
12 month period. Duncan (1974) recorded an average litter
size of 3.2 (range 1 - 5). Singer et al. (1978) recorded
an average pre-natal litter size of 4.75 (range 3 - 7) and an average post-natal
litter size of 3.03 (range 1 - 5). Up until six months of age, young hogs
possess dark longitudinal stripes on their bodies. Permanent tusks begin to
grow at about one year, and sexual maturity is attained within the first
year of life.
- Longevity
Nowak (1991) noted that average longevity in feral pigs
is about 10 years, but some have lived as long as 27 years.
- Terrestrial Ecology
Wild hogs may be active at any time during the day or night. During the
warmer months, they tend to be nocturnal in order to avoid the daytime heat.
Movements are generally nomadic and are brought about by food availability.
Hogs have keen senses of smell and hearing.
Most hog observations are of single individuals or small groups usually
consisting of a sow and her young. Average group size was 1.87 in a 1977 park
study (Singer et al., 1978).
Wild hogs are omnivores and are seasonal in their feeding habits (Ackerman et al., 1977). In March and April, they move into the
higher elevation northern hardwood forests near the state line. They move back
to lower elevations in August and feed primarily on mast, invertebrates, and
small vertebrates. During the spring and early summer in the northern hardwood
forest, the diet consists of springbeauty corms (Claytonia virginica)
(58%), leaves and stems from mesic herbs (28%), other roots (11%),
macroinvertebrates (2%), and leaves of shrubs (1%). Approximately 70% of the
diet is subterranean in origin (Singer, 1981).
Invertebrates such as walking-sticks, hellgrammites, beetles, caterpillars,
fly larvae, millipedes, centipedes, snails, earthworms, and crayfish are
present in almost every stomach, but their volume is low. Likewise, the
frequency of vertebrates is high, but the percent volume is low. Salamanders,
particularly the endemic red-cheeked salamamder (Plethodon jordani),
are common at the higher elevations. An average of 1.75 salamanders per stomach
were recorded. Hard mast (Quercus spp., Carya spp.) normally
comprises 60 to 85% by volume of the wild hog diet (Scott and
Pelton, 1975), in late summer.
Huff (1977) reported that rooting by hogs stimulates
vegetative reproduction of American beech (Fagus grandifolia), with root
suckers being 4 to 44 times greater than in undisturbed plots. Studies of high
elevation beech gaps in the park show that beech also respond to rooting by wild
hogs with increased height growth. The shoots of beech trees in moderately and
severely rooted sites were significantly longer than those for trees in lightly
rooted sites (Lacki and Lancia, 1986). Bratton (1974) reported that herbaceous cover is drastically reduced in
hog-disturbed sites when compared to undisturbed sites.
The enterococci Streptococcus faecalis and Streptococcus faecium
have been recorded from fecal specimens by Mundt (1963).
- Predators and Defense
The wild hog has few predators. Bobcats prey on young pigs, and both young
and adult hogs may be preyed upon by black bears and coyotes.
- Parasites
None recorded from the park.
Conservation Biology
- Special Protection Status
- Rangewide:
None.
- In Park:
All plants and animals are protected within
Great Smoky Mountains National Park.
Collection requires a permit which is usually
granted only for research or educational purposes.
Links to Other Sites
Acknowledgements
- Text
- Photographs
- Map development
- Web page design & coding
- Denise Lim, University of Georgia, Athens
- John Pickering, University of Georgia, Athens
References
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Ackerman, B. B., M. E. Harmon, and F. J. Singer. 1978 (1977).
Studies of European wild boar in the Great Smoky Mountains National
Park. Part II. Seasonal food habits of European wild boar. Report for
the Superintendent, Great Smoky Mountains National Park. In Great
Smoky Mountains National Park library.
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Duncan, R. W. 1974.
Reproductive biology of the European wild hog (Sus scrofa) in
the Great Smoky Mountains National Park. Master's thesis, University of
Tennessee, Knoxville.
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Fox, J. R. and M. R. Pelton. 1977.
An evaluation of control techniques for the European wild hog in the
Great Smoky Mountains National Park. Pages 53-66. In: Wood, G. (editor).
Research and management of wild hog populations. Baruch Forest Science
Institute, Clemson University, Clemson, South Carolina.
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Jones, P. 1957.
The European wild boar in North Carolina. Game Division, Raleigh: North
Carolina Wildlife Resources Division.
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Kellogg, R. 1939. Annotated list of Tennessee mammals. Proceedings of the
U.S. National Museum 86 (3051): 245-303.
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Lacki, M. J., and R. A. Lancia. 1986. Effects of wild pigs on beech
growth in Great Smoky Mountains National Park. Journal of Wildlife
Management 50 (4): 655-659.
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Linzey, D. W. 1995a.
Mammals of Great Smoky Mountains National Park. Blacksburg,
Virginia: The McDonald & Woodward Publishing Company, Inc.
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Linzey, D. W. 1995b.
Mammals of Great Smoky Mountains National Park-1995 Update.
Journal of the Elisha Mitchell Scientific Society 111(1):1-81.
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Mundt, J.O. 1963. Occurrence of enterococci in animals in a wild
environment. Applied Microbiology 11: 136-140.
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Nowak, R. M. 1991.
Walker's Mammals of the World. 5th edition.
2 volumes. Baltimore: The Johns Hopkins University Press.
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Scott, C. D., and M. R. Pelton. 1975. Seasonal food habits of the
European wild hog in the Great Smoky Mountains National Park.
Proceedings of the Southeastern Association of Game and Fish
Commissioners 29: 585-593.
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Singer, F. J. 1981.
Wild pig populations in the national parks. Environmental
Management 5 (3): 263-270.
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Singer, F. J. and B. B Ackerman. 1981.
Food availability, reproduction, and condition of European wild boar
in Great Smoky Mountains National Park. National Park Service
Research/Resources Management Report 43.
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Singer, F. J., B. B Ackerman, M. E. Harmon, and A. R. Tipton. 1978.
Studies of European wild boar in the Great Smoky Mountains National Park;
Part I. Census, trapping and population biology of European wild boar-1977.
National Park Service Southeast Regional Office Report for the Superintendent.
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Stegeman, L. C. 1938.
The European wild boar in the Cherokee National Forest, Tennessee.
Journal of Mammalogy 19 (3): 279-290.
Last modified: 10 April, 2002