Feral hogs (also called wild hog; Sus scrofa) are preyed on by several natural (that is, nonhuman) species of carnivores and omnivores in the United States. However, man is still unquestionably the primary and most significant predator of non-native feral hogs. For the most part, predation by natural species is thought to represent only a minor role in the mortality of feral hogs throughout their range. Further, most of this predation is directed toward the younger age classes within a feral hog population. The following are species accounts of what is known about the various native and non-native natural predators in the United States that have been either documented or are thought to have the potential to prey on feral hogs.
American Alligator – The predation of feral hogs by alligators has been well documented in both the scientific and popular literature. However, alligator predation on this invasive species has been described as being either opportunistic or limited. Alligators have been known to take a variety of sizes of feral hogs, even being able to catch and kill very large hogs that are swimming across open water. In fact, the open water capture and drowning of feral hogs is probably the most common manner in which this type of predation occurs. In other instances, alligator have been observed to rush, catch, and then drown feral hogs that were standing near the water's edge. The overall impact of alligator predation on a feral hog population would be minimal.
Turkey Vulture – Primarily a scavenger, this vulture species is also opportunistic in its foraging habits. In one reported account in an open rangeland area of south Florida, three adult turkey vultures were observed to fly in, surround, and stop a feral piglet's escape with their outstretched wings. Using stabbing strikes with their beaks, the trio was then able to kill their victim, which they then consumed. The piglet was small and, by its lethargic behavior, did not appear to be completely healthy. Given the circumstances, predation of feral hogs by this avian scavenger would be a possible but extremely rare event.
Red-tailed Hawk – Although typically a predator of small birds and mammals, the red-tailed hawk will prey on small feral piglets given the right circumstances. Observations of this hawk species preying on feral piglets on Ossabaw Island off of the Georgia coast have been reported on three occasions. The more open habitat found on Ossabaw Island may have enabled the success of these predatory attempts. In addition, the small size and high percentage of solitary piglets within that feral hog population may account for these multiple observations of this type of predation.
Golden Eagle – Typically a predator of small mammals taken on the ground, the golden eagle has been documented to opportunistically prey on feral piglets. This is also true within the Eurasian portion of this raptors' species range. In general, this type of predation is neither common nor widespread. However, the presence of a large prey base in the form of feral piglets has been theorized to have caused the establishment of nesting golden eagles on the California Channel Islands. When the islands’ various feral hog populations were either eradicated or reduced, the then resident golden eagles began to prey on the indigenous island foxes, almost driving this already threatened species to extinction.
Owls – Owls have been anecdotally reported as predators of small feral hogs and piglets; however, no further details on the species of owl or the associated circumstances were provided in these accounts. Given its potential to prey on other animals of comparable size, the great horned owl would represent a potential predator of feral piglets in this country. The Eurasian eagle owl, an Old World species that is closely related the great horned owl, has been documented as a predator of wild piglets.
Feral Dog – Present in most states, feral dogs represent a known predator of feral hogs in this country. The predatory impact of feral dog packs would be mostly realized toward piglets and shoats within a feral hog population.
Coyote – A common native canid that has expanded its range throughout most of the continental United States, the coyote has been documented as preying on feral hogs in a number of locations. Most coyote predation of feral hogs is directed at younger or smaller animals. Overall, the predatory impact of coyotes on feral hogs is unknown. The presence of feral hog remains in coyote stomachs and scats could be the result of either direct predation or carrion scavenging. Because of an increased presence of these remains during hunting seasons, two studies have suggested that scavenging of carcasses was the primary source of feral hogs in coyote diets.
Red Wolf – Effectively extinct in the wild, the red wolf has been reintroduced onto Bull's Island, South Carolina, into the Alligator River National Wildlife Refuge (ARNWR), North Carolina, and into the Great Smoky National Park (GSMNP), North Carolina and Tennessee. Prior to their removal from the wild in the GSMNP, the red wolves there were documented to prey on hogs in the southern portion of the park. Feral hogs have also recently been found on the ARNWR; however, there have been to date no reports of red wolf predation on these hogs.
Red Fox – The red fox was reported as a potential predator of very young piglets in eastern Tennessee; however, no specific accounts exist reporting the predation of feral piglets by this fox species in the United States. However, there are several reported accounts of predation on wild piglets by red fox in both Europe and Asia.
Gray Fox – Like the red fox, this species has been identified as having the potential to prey on very young feral piglets on occasion. One study, which looked at gray fox diet in areas with hogs, found the presence of only a small amount of feral hog remains, and that was reportedly the result of scavenging by this small canid.
Black Bear – The black bear is known to prey on feral hogs of all ages; however, the impact of predation by this bear on feral hog populations is not known. Some researchers have speculated that black bears probably kill few if any feral hogs, especially given that an adult hog would represent a formidable adversary for a black bear. In fact, in the 1920s a feral boar in the Okefenokee Swamp was reported to have killed a black bear in a fight between the two animals. Similar accounts of feral boars killing bears during fights in the Ozark Mountains of Arkansas were reported in the 1880s. Being opportunistic, black bears have been reported to raid nylon net live traps used for feral hog control at high elevations in the GSMNP to obtain any trapped hogs contained within these devices.
Small Indian Mongoose – This introduced mongoose has been reported to prey on feral piglets in the Hawaiian Islands. An investigation of mongoose stomach contents on Maui revealed feral hog remains in five of the 18 stomachs analyzed. However, it was not possible to establish that this was not the result of carrion feeding as opposed to direct predation. Accounts also exist of this same species of mongoose preying on young free-ranging domestic pigs in Jamaica.
Bobcat – This small wild cat is found in most areas where introduced feral hog populations exist in this country. The predation of feral piglets by bobcats has been documented in both scientific and popular accounts. In the Southeast, bobcats have been reported by some studies as being important predators of young wild piglets. However, most studies have shown that feral hogs were not a major component of the bobcat diet.
Ocelot – Although neither common nor widespread, this small neotropical cat has been documented to prey on feral hogs in south Texas. Feral hog remains were found in 21 percent of ocelot scats examined from the Lower Rio Grande Valley. In addition, ocelots were reported to be fond of young domestic pigs as prey in Texas in the early 1900s.
Mountain Lion or Cougar – The large cat is found to overlap the range of feral hogs in several western states and in Florida. In both general regions mountain lions have been documented to prey on introduced feral hogs. The target animals include both sexes and potentially any age class. Given the right situation, a mountain lion could catch and kill a fairly large sow or boar. Although variable from area to area, feral hogs can constitute a significant volume of prey in the diet of this large predator.
Feral hog – Cannibalism or predation of feral hogs by other individuals within that same population has been documented to occur. Such predation would be primarily directed at immature animals. The most likely instance would involve the predation of unattended newborn piglets by adult boars. The impact of this type of predation is unknown. Based on extensive zoo experience with captive wild hogs, some researchers believed that such reported predation of young piglets by adult boars was unfounded.
Potential Natural Predators – Based on their overlapping range with feral hogs in this country and the fact that these predators have been documented to prey on wild hogs elsewhere, four additional potential predators of feral hogs in this country would include the Burmese python, gray wolf, lynx, and jaguar. However, in spite of this potential, none of these four species have been documented to prey on feral hogs in the United States to date.
In summary, the list of known and potential natural predators of feral hogs in the United States is longer than had been heretofore reported. However, because the predation by these species is largely opportunistic in nature, the impact on local feral hogs on an annual basis would be minor under most circumstances. Mountain lions are reported to be the only predator that uses feral hogs as prey on a regular basis; however, the percentage of hogs in a lion's diet appears to be prey density dependent in any one given area. With the possible exception of alligators and black bears, most other species identified above would constitute only an incidental or infrequent opportunistic predator of immature feral hogs. As such, natural predators do not have the potential to be able to significantly reduce the number of individuals in a local feral hog population.