Domestic swine (Sus scrofa) were introduced to the United States as a food source in the 1500s, and Eurasian wild boars were introduced as an animal for sport hunting in the 1800s. Individuals from both of these stocks escaped and formed feral populations, ultimately resulting in the wild pig. With an estimated 8-10 million wild pigs in the US, this invasive, non-native species poses a threat to native wildlife and agriculture. Wild pigs are opportunistic omnivores, feeding on vegetation, invertebrates, and vertebrates such as birds, mammals, and reptiles and amphibians. In fact, reptiles and amphibians are often the vertebrate group that are most threatened by wild pigs (Taylor and Hellgren 1997).
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| Wild pigs are predators of reptiles and amphibians. |
Wild pigs primarily eat vegetation, but animal
matter can annually make up about 10% of their dietary consumption (Ditchkoff
and Mayer 2009). Reptiles and amphibians
are likely consumed incidentally because there are typically not large numbers
of herpetofauna in stomach content analyses. However, there is evidence of wild pigs
actively seeking out reptiles and amphibians to consume. In a food habit study conducted by Jolley et
al. (2010), one wild pig had 49 eastern spadefoot toads (Scaphiopus holbrookii) in its stomach. This high number suggests that wild pigs can
and do actively hunt. Explosive-breeding
amphibians such as the eastern spadefoot toad are at greater risk of being
actively depredated because they gather in large concentrations to breed. Reptiles that nest on the ground are also
likely to lose their eggs to wild pigs (Taylor and Hellgren 1997); wild pigs
are major nest predators of threatened and endangered sea turtles such as
loggerhead (Caretta caretta) and
leatherback (Dermochelys coriacea)
sea turtles (Lewis et al. 1996). Even
species that are more concealed are not out of harm’s way. The northern snake-necked turtle (Chelodina rugosa) in Australia
half-burrows itself in mud and aestivates in dry years. Wild pigs locate and dig up them up, which not
only drastically lowers survivorship of the turtles, but it also takes away a
food resource from indigenous peoples (Fordham et al. 2006).
Local herpetofauna is not only at risk from predation, however. Wild pigs are ecosystem engineers, which are animals that have a large, and in the case of pigs, negative effect on the landscape. Wild pig activities such as rooting alter habitat characteristics like reducing plant cover (Barrios-Garcia and Ballari 2012), which can affect the microclimates needed by some reptiles. Wild pigs also wallow in water to keep cool, which increases sedimentation in the water and damages the surrounding banks (Timmons et al. 2011). These areas are important habitat for salamander larvae and the Texas-threatened Rio Grande lesser siren (Siren intermedia), and wild pig activity may lead to declines in both populations (Enge 2005, Taylor and Hellgren 1997).
There are multiple ways that landowners can reduce wild pigs on their property in order to avoid substantial economic and ecological damage by wild pigs. Videos about trapping and other management techniques can be found at the Texas A&M Wildlife and Fisheries Extension YouTube page. Publications and other written documents about wild pig management can be found on the Texas A&M AgriLife Bookstore. Additional resources are available at feralhogs.tamu.edu.
The hyper-linked resource document below will provide you with quick access to many of our online feral hog resources including publications, fact sheets and videos.
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| Explosive breeders such as this southern leopard frog (Lithobates sphenocephalus) are at greater risk from wild pig predation. |
Local herpetofauna is not only at risk from predation, however. Wild pigs are ecosystem engineers, which are animals that have a large, and in the case of pigs, negative effect on the landscape. Wild pig activities such as rooting alter habitat characteristics like reducing plant cover (Barrios-Garcia and Ballari 2012), which can affect the microclimates needed by some reptiles. Wild pigs also wallow in water to keep cool, which increases sedimentation in the water and damages the surrounding banks (Timmons et al. 2011). These areas are important habitat for salamander larvae and the Texas-threatened Rio Grande lesser siren (Siren intermedia), and wild pig activity may lead to declines in both populations (Enge 2005, Taylor and Hellgren 1997).
 |
| Wild pig wallows along stream and river banks damage amphibian habitat. |
Already
threatened or endangered species are at increased risk for population loss due
to wild pigs. According to a study by
Jolley et al. (2010), a little over 3,000 wild pigs consumed an estimated 3.16
million reptiles and amphibians—in one year.
This illustrates the substantial effect wild pigs can have on local
populations, especially species that pulse-breed, ground-nest, or rely on
water; traits such as these make them more vulnerable to both predation and harmful
habitat modification.
 |
| Wild pigs may negatively impact Texas horned lizards (Phrynosoma cornutum) by direct predation or habitat conversion (Taylor and Hellgren 1997). |
There are multiple ways that landowners can reduce wild pigs on their property in order to avoid substantial economic and ecological damage by wild pigs. Videos about trapping and other management techniques can be found at the Texas A&M Wildlife and Fisheries Extension YouTube page. Publications and other written documents about wild pig management can be found on the Texas A&M AgriLife Bookstore. Additional resources are available at feralhogs.tamu.edu.
The hyper-linked resource document below will provide you with quick access to many of our online feral hog resources including publications, fact sheets and videos.
Literature cited
Barrios-Garcia,
M. N. and S. A. Ballari. 2012. Impact of wild boar (Sus scrofa) in its introduced and native range: a review.
Biological Invasions 14: 2283-2300.
Enge,
K. M. 2005. Herpetofaunal drift-fence surveys of steephead ravines in the
Florida Panhandle. The Southeastern Naturalist 4: 657-678.
Fordham,
D., A. Georges, B. Corey, and B. W. Brook. 2006. Feral pig predation threatens
the indigenous harvest and local persistence of snake-necked turtles in
northern Australia. Biological Conservation 133: 379-388.
Jolley,
D. B., S. S. Ditchkoff, B. D. Sparklin, L. B. Hanson, M. S. Mitchell, and J. B.
Grand. 2010. Estimate of herpetofauna depredation by a population of wild pigs.
Journal of Mammalogy 91: 519-524.
Lewis,
T. E., D. Atencio, R. Butgereit, S. M. Shea, and K. Watson. 1996. Sea turtle
nesting and management in northwest Florida. Pages 162-166 in J. A. Keinath, D. E. Barnard, J. A. Musick, and
B. A. Bell, editors.
Proceedings of the fifteenth annual workshop on sea turtle biology and
conservation. NOAA Tech. Memor. NMFS-SEFSC-387.
Taylor,
R. B. and E. C. Hellgren. 1997. Diet of feral hogs in the Western South Texas
Plains. The Southwestern Naturalist 42: 33-39.
Timmons,
J., J. C. Cathey, N. Dictson, M. McFarland.2011. Feral hogs and water quality
in Plum Creek. Texas AgriLife Extension Service, Texas A&M University
System.