Texas is home to an estimated 2 million feral hogs (Sus scrofa), about 50 percent of all the feral hogs in the U.S. From the panhandle to the Gulf coast, from the arid southwest to the eastern pineywoods, feral hogs may be found in nearly every Texas county.
The population and range of feral hogs have expanded dramatically because they are extremely adaptable animals with a high reproductive rate. Relocation by hunters, disease control in domestic animals, the management of rangelands, and habitat improvements made for livestock and wildlife also have helped feral hogs. Hogs are prized by hunters but despised by landown- ers who suffer from their damage.

Feral Hog Distribution in Texas
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History
Hogs are an Old World species that has existed since before the Ice Age. Evidence indicates that early man hunted and ate feral swine and that these animals continued to thrive throughout the Stone
Age in Europe and Asia. Hogs may have been domesticated about 7000 B.C. Explorers such as De Soto, Cortes and LaSalle brought them to the New World. They have been in Texas since the 1680s and were important live- stock to the early settlers, who usually allowed their animals to roam free. When confronted by war and economic hard times, settlers often had to abandon their homesteads on short notice, leaving their animals to fend for themselves. Thus, many free-ranging domesticated hogs became feral over time.
Feral hogs have adapted to every region of the state and can be found in forests, swamps, brushy lands and deserts.

  
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Identification
The three strains of wild hogs in Texas are the Eurasian, the feral (escaped or released domestic hogs), and hybrids of these two. Few, if any, pure Eurasian hogs remain. Coat color, pattern and bristle length can help identify the strain of feral hog.
The term “feral hogs” applies collectively to Eurasian wild boars (i.e., Russian boars), domesticated hogs that have become feral, and hybrids of these two. Feral hogs also have been called European wild hogs, wild boars, razorbacks, pineywoods rooters, woods hogs and other more "colorful" names. All these names refer to the same species of swine. However, it is important to note that the hog-like collared peccary, or javeli- na (Tayassu tajacu), a native species of the southwestern U.S., belongs to a different family and is not a feral hog.
Eurasian Wild Boars
Eurasian wild boars have longer legs, larger heads, longer snouts, and a larger head-to-body ratio than other feral hogs. They have shorter, straighter tails than feral hogs or hybrids. The coat usually consists of light brown to black bristles with cream to tan tips. The back of the head and part of the rostrum are covered with brown to black bristles with white tips. The under- side is lighter in color (cream to smoky gray) and the legs, ears and tail are darker than the rest of the coat–usually dark brown or black bristles with no light-colored tips. Bristles of the pure Eurasian hog are the longest and thick- est of all types and usually have multiple splits at the tips. Eurasians have no neck wattles or syndactylous (joined or webbed) digits, as have been found in the other types of wild swine.

   
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The javelina, a native of the southwestern U.S., is often confused with the feral hog, although they are not closely related.
Texas ranchers and sportsmen released Eurasian wild boars for hunting in the 1930s. Many of these animals escaped and began breeding with feral hogs that were already free ranging. This led to the decline of the pure Eurasian strain; there are now few, if any, in Texas.
Feral Hogs
Feral hogs are domestic hogs that have escaped or been released into the wild. With each generation the animals' domestic characteristics diminish as they develop the traits necessary to survive in the wild.
Their original breed and their nutrition during development determine the size and color of feral hogs. Coat color and pattern are highly variable. Solid black is the predominate color, but hogs also may be brown, red, white, spotted, belted (black or brownish red with a white band across the shoulders and forelimbs) or have rare blue or gray roan patterns. Bristles of feral hogs are shorter than those of Eurasian boars and hybrids. Bristles are less thick than those of Eurasians but thicker than those of hybrids. Bristles are a solid color and split at the tips. The underfur and bristles are the same color Feral hogs may have neck wattles and syndactylous (webbed) digits.
Hybrids
Hybrid hogs are crosses between Eurasian boars and feral hogs and have characteristics of both. Coat color and pattern can resemble that of Eurasian boars, feral hogs, or any combination of the two. Bristles are shorter than in Eurasians but longer than in feral hogs, and not as thick as either of the other two. The bristles have split tips. The underfur varies from black to a whitish or smoky gray and may be a different color than the bristles. Hybrids may have neck wattles and syndactylous digits.
Biology and Ecology
Feral hogs are so adaptable to different environments, so adept at sur- vival, and have such a high reproductive rate, that their population has exploded. This has made them significant pests in much of Texas.
Feral hog boars weigh an average of 130 pounds; sows average 110 pounds. However, much larger hogs have been documented. This hog weighed 465 pounds.
Characteristics
Overall, feral swine are smaller, leaner, and more muscular than their domestic counterparts. Average boar and sow weights are about 130 pounds and 110 pounds, respectively, although the largest adults may weigh more than 400 pounds and be more than 3 feet tall and 5 feet long. Males have larger heads and tusks than females. Compared to domestic swine, feral hogs have more well-developed shoulders, longer and larger snouts and tusks, smaller and mostly pricked ears, longer and coarser hair, and straighter tails (with a bushy tip).
Some feral hogs develop a mane or crest of hair on their necks and backs that can be raised when they are angered. This is the reason for the nick- name “razorback.” Juveniles of all types of wild swine may have striped pat- terns that disappear as the hogs mature. Longitudinal striping is rarely seen in domestic hogs.
Feral hogs have rounded body contours, short legs, and cloven-hoofs with four toes, two of which have been modified into large dewclaws. Males develop thick areas of tough skin, cartilage and scar tissue on their shoulders. This area, called the shield, develops continually as the hog ages and fights and may be up to 2 inches thick.

  
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Juveniles of all types of wild swine may have stripes that disappear as they mature.
Feral hogs have poor eyesight but excellent hearing and sense of smell. Their flattened snouts allow them to root in the soil (left photo). Male feral hogs have four canine teeth, called tusks, that grow contin- ually. They are used for defense and to establish dominance. If the upper tusk is damaged or deformed, the corresponding lower tusk may continue to grow in a complete circle (right photo).
Feral hogs have poor eyesight but excellent senses of hearing and smell. Their specially developed snouts are flattened and strengthened by a plate of cartilage, which allows them to root in all types of soil.
Hogs have 44 teeth; the molars have low crowns with simple cusps. The permanent teeth are in place by the time a hog is 22 months old. Males of all three types of wild swine have four continually growing tusks (canine teeth) that they use for defense and to establish dominance for breeding. Tusks project from the sides of the mouth, can be extremely sharp, and may grow 5 inches before they are broken off or worn down from use. The upper tusks (sometimes called witters or grinders) function as whetstones to the lower tusks, keeping them sharp. If an upper tusk is damaged or deformed, the corresponding lower tusk can continue to grow in a complete circle and re-enter the lower jaw.

 
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Female feral hogs may have as many as 10 to 13 piglets per litter. With adequate nutrition, a feral hog population can double in 4 months.
Reproduction
Feral hogs are the most prolific large, wild mammal in North America. With adequate nutrition, a feral hog population can double in 4 months. Breeding occurs throughout the year when conditions are favorable, and sea- sonally when food supply and nutrient quality vary. Females begin breeding at about 8 to 10 months old, or as young as 6 months if food is abundant. Under favorable conditions, sows can produce two litters every 12 to 15 months, with an average of four to eight piglets per litter and a sex ratio of 1:1. Younger sows tend to have smaller litters, while an older sow may have as many as 10 to 13 piglets. Piglets are weaned in 2 to 3 months. Drought and food shortages can delay breeding and reduce the number of piglets born, but feral hog populations recover quickly when conditions improve.
Habitat
Feral hogs have adapted well to a wide range of ecosystems in Texas. They prefer moist bottomland and are commonly found in riparian areas near rivers, creeks, streams, lakes, ponds, marshes, bogs, swamps and sloughs. They also prefer dense vegetation that conceals them and protects them from temperature extremes. Only poor habitat and extremely arid conditions seem to limit their distribution. Hogs usu- ally concentrate where food is plentiful. They may rest during the day in dense, shady areas and move at night to more open areas for food and water.
Feral hogs can be found in many different habitats, but prefer moist bottomland and riparian areas.

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Feral hogs usually travel in family groups, or sounders, made up of two or more sows and their young. Boars are normally solitary, joining a group only to breed.
Behavior
Feral hogs are mostly social animals and tend to travel in family groups. A basic group, called a sounder, consists of one or more sows and their young. Weaned pigs remain with their mother until another litter is due or until they have mated. Other groups may consist of young females, bachelor males, or other combinations. Adult boars older than 18 months are almost always solitary animals that rejoin groups only to mate or to feed on a partic- ular food source. Farrowing sows will temporarily separate themselves from a group. Group sizes vary considerably by region and season. Groups normally consist of two to 20 individuals, but as many as 40 or 50 animals may come together during dry seasons or drought.
Home range is largely influenced by the abundance of food. Feral hogs (particularly boars) may travel as much as 15 miles in search of adequate food and/or water. Hogs in areas where food is scarce have larger home ranges than those where food is adequate. Therefore, fall and winter ranges are generally larger than spring and summer ranges. Home ranges vary from 0.4 to more than 19 square miles, but normally are 0.5 to 3 square miles. Unlike territorial animals, feral hogs do not travel throughout their entire range in short periods of time, but rather traverse the area randomly throughout the season. Boars have larger daily, seasonal and overall home ranges than sows. Sows with newborn young will stay in a very small area during the piglets’ first couple of weeks of life.
Feral hogs are usually nocturnal. They may be active for a while during early morning or late afternoon, but only when temperatures are conducive and when seeking suitable shelter and wallowing areas. They seldom move around at mid-day unless disturbed. Major disturbances can cause feral hogs to permanently shift their home range several miles away. Infrequent or minor disturbances will cause hogs to move only a short distance, and they will return once the disturbance has passed.

  
Feral hogs are opportunistic omnivores; they eat almost anything and everything they find.
Food
Feral hogs require high energy foods with lots of protein, so their diet is largely determined by the nutrient levels of the foods available at a given time and will vary seasonally and regionally. They may become semi- nomadic to locate an abundant source of suitable food.
Feral hogs are opportunistic omnivores, eating almost anything and everything they find. They prefer succulent green vegetation (they do not digest cellulose well) along with a variety of animal material, fruit and grain. In the spring they eat grasses, forbs, roots and tubers. In the summer and fall they eat mostly soft and hard mast such as prickly pear cactus, mesquite, guajillo, huisache, grapes, plums, acorns and persimmons. Rhizomes, bulbs and tubers are also important food items during the fall. Winter diets consist mainly of grasses, forbs and agricultural grains such as corn, milo, wheat, oats, rice and soybeans. They also eat peanuts, pumpkins, watermelons, potatoes, cantaloupes and orchard fruit. Shelled corn put out as supplemen- tal feed for wildlife attracts feral hogs and can be a major part of their diet. They readily consume carrion and animal matter, including arthropods (especially beetles), amphibians, reptiles, eggs, birds, small mammals, and the young of wild mammals and livestock. Large feral hogs also may cannibalize pigs and shoats.
Mortality
When conditions are good, feral hogs live an average of 4 to 5 years. Some live as long as 8 years. Mortality among juveniles, particularly during the first 3 months of life, is extremely high, but tapers off slightly through- out the first year. Juveniles may die from accidental suffocation by sows, star- vation, parasites, disease, accidental death, hunting and predation. Adults are sometimes killed by coyotes, bobcats, mountain lions, large raptors and feral dogs.
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Hogs root in the ground to find food. They can damage suburban yards and golf courses as well as agricultural land.
Signs
The presence of feral hogs is usually fairly easy to determine. In addition to sighting them, one may find tracks, trails, crawls, rooting, wallows, rubs and scat (droppings).
Hogs root or dig in the ground to find food. Rooted areas can be exten- sive and cover several acres. If the soil is soft, rooted areas can be as much as 3 feet deep. Feral hogs are persistent and will methodically root an area until the food is depleted.

  
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During warm weather feral hogs wallow in moist areas to coat themselves with mud. This helps them stay cool and protects them from insects and the sun.

  
Rubs on trees, logs, posts, poles and rocks indicate the presence of feral hogs.
Tracks can be difficult to identify because they are similar to those of deer, sheep and goats. Hog tracks are wider than they are long and shorter than a deer track of the same width. A distinguishing characteristic is the appearance of rounded or blunt toes in hogs as opposed to more pointed toes in deer. Both deer and hog tracks may show dewclaw marks in soft ground. Contrary to popular belief, dewclaws do not determine an animal's sex or age. However, the relative size of a track can indicate an animal's sex or age.
During the warmer months, feral hogs create wallows in moist areas. These muddy depressions help the hogs keep cool and coat them with mud that protects them from the sun and from insects. In hot weather hogs will lie in wallows during the day.
Feral hogs consistently use the same trails and crawls, often traveling underneath and through fences when roaming from site to site. Coarse hair found hanging on fence wires is a sign of hogs. Marks from rubbing or tusk- ing on trees or logs along trails also indicate the presence of feral hogs. Rubs are often found near wallows. Rubbing is done to scratch the skin and remove dried mud, hair and parasites. Trees, fallen logs, fence posts, rocks and power poles are commonly used for rubbing. Hogs seem to have a real affinity for rubbing on power poles treated with creosote. Any such poles within a hog’s home range will usually have visible rubs.
Where there are feral hogs, scat can usually be found. Scat deteriorates quickly and can be highly variable in appearance, which makes identification difficult. Generally, feral hog scat has the same shape and consistency of dog droppings. Examining scat can reveal what the hog has been eating, which is useful when considering whether or not to control hogs.
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Damage and Disease
Feral hogs cause various kinds of agricultural and environmental dam- age, mostly by rooting, wallowing and depredation. They also compete with wildlife and livestock for habitat, harbor endemic and exotic dis-
eases, and transmit parasites to domestic livestock and humans. As their pop- ulations continue to expand across the state, their damage will increase as well.

   
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Agricultural Damage
Hogs will feed on almost any agricultural crop they find, especially crops adjacent to riparian areas. They eat seeds, seedlings, mature crops, hay, turf and gardens. Their rooting and trampling also damages crops. The financial losses to agricultural producers can be staggering.
Feral swine compete with livestock by rooting up and eating vegetation intended for livestock feed. Rooting creates troughs or mounds that can damage farm equipment and injure livestock. Rooting can also affect the plant composition of a pasture by promoting the growth of undesirable plants where hogs have destroyed desirable forage grasses. Once pastures are degraded in this way, landowners must spend considerable money and time restoring them to pre-swine conditions. Swine wallowing can severely muddy ponds and streams and cause algae blooms, oxygen depletion, bank erosion and soured water. This is particularly true when drought condi- tions concentrate large numbers of hogs around a few water sources.
Feral hogs consume supplemental food and damage feeders and food plots intended for livestock and wildlife. When hogs fre- quent these sites other animals often avoid them.
Fence damage–torn netting, holes, and weakened wires and posts–can allow livestock to wander, give access to predators, and result in costly repairs. Hogs are so persistent and strong that they can breach all but the most expensive and sturdy fence.
Crops such as sorghum, rice, wheat, corn, soybeans, potatoes, watermelon, cantaloupe, pecans and peanuts are often damaged by feral hogs.
Hogs not only eat crops, but also root them.

  
Extensive rooting can destroy native plants and pastureland, which can cause soil erosion.
Environmental Damage
Measuring the environmental impact of feral hogs can be difficult. Most important is the destruction of the habitat of native wildlife and the preda- tion of wildlife. Feral hogs compete for food with many other animals, including white-tailed deer, javelina, turkey, bobcat, and various small mam- mals. Swine often deplete specific food sources on which other species depend for survival. Extensive rooting of soils, forest litter and grasslands can cause serious erosion of riparian areas, which leads to siltation, lower water quality, and sometimes fish kills. Rooting may also disrupt native plants and change the plant and animal community.
Predation
Predation of livestock and wildlife by feral hogs can be a serious problem in some areas. When the opportunity presents itself, hogs prey upon kids, lambs, calves, deer, fawns, ground-nesting birds, and a variety of other ani- mals. Some hogs become highly efficient
predators. They generally prey upon young
animals but will kill injured or weak adults.
Feral hogs are often attracted to birthing
grounds, where they feed on afterbirth and
fetal tissue. In certain areas, feral hogs may
cause significant losses to endangered or
threatened wildlife species.

Hog predation can be hard to detect because hogs often eat the entire animal, leav- ing little or no evidence. Tracks, scat and other hog signs that confirm the presence of hogs are usually needed to confirm predation. However, hogs are both predators and scav- engers, so even the presence of hogs at a kill site isn't proof that hogs made the kill. Hogs
Feral hogs prey on livestock and wildlife, and can seriously threaten endangered species.
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may not be suspected when predation occurs, but they may be responsible more often than is thought.
Diseases and Parasites
Feral hogs are susceptible to a variety of infectious and parasitic diseases. The more hog populations increase and expand, the greater the chances that they may transmit disease to other wildlife, to livestock and to humans. External parasites that infest feral hogs include fleas, hog lice and ticks. Internal parasites include roundworms, liver flukes, kidneyworms, lung- worms, stomach worms and whipworms. Hog diseases that could have severe repercussions for agribusiness include swine brucellosis, pseudorabies, lep- tospirosis, tuberculosis, tularemia, trichinosis, plague and anthrax. Exotic or foreign diseases of concern include foot and mouth disease, African swine fever, hog cholera and swine vesicular disease.
Swine brucellosis is a bacterial disease of animals and humans. It causes abortions in sows and can cause infertility in boars. It is a threat to the swine industry. It is transmitted through reproductive discharges (semen and after- birth) and, once infected, a hog is a carrier for life. Brucellosis is contagious to humans; chronic symptoms range from severe flu to arthritis and menin- gitis. Humans can be treated with antibiotics, but there is no cure for live- stock.
Pseudorabies, a viral disease, attacks the central nervous system and can be fatal to cattle, horses, goats, sheep, dogs, cats, raccoons, skunks, opossums and small rodents. It is not related to rabies and it does not infect humans. Pseudorabies is a special concern to swine producers because it causes abor- tions and stillbirths. Once infected, hogs are lifetime carriers and periodically shed the virus through their noses and mouths. Livestock can be infected by direct contact with infected animals, consuming contaminated feed or water, or contacting contaminated equipment. Vaccinating livestock, particularly swine, may help to curb the spread of the virus.
Anthrax is a soil-borne disease that occurs irregularly in Texas, usually where the daily minimum temperature is at least 60 degrees F, where wet periods are followed by long dry periods, and where soils are alkaline or neu- tral. All mammals, especially ruminants, are susceptible to anthrax. Feral hogs may come into contact with the bacteria while feeding or by interacting with infected animals. Humans can contract the disease from contaminated soil or animals. Vaccines are available for both humans and livestock.
Foot and mouth disease is a foreign animal disease of great concern because it is highly contagious, spreads rapidly, can cause serious economic losses, and can constrain international trade in livestock products. It is a viral disease of ungulates (mainly cloven-hoofed ruminants, including swine) and some rodents. It does not affect humans, but humans can spread the virus. There is no known cure. Symptoms include fever and blister-like lesions on the tongue, teats, lips, inside of the mouth, and between the hooves. Many infected animals recover, but are permanently debilitated. The virus can be spread by contact with infected animals and with contaminated feed, water or equipment.
Livestock should be vaccinated appropriately, especially if they may have contact with feral hogs. Anyone who handles a feral hog should wear rubber gloves, particularly if there is contact with blood or reproductive organs. Feral hog meat should be thoroughly cooked before it is eaten.
Control Methods
Once feral hogs have become established in an area it is nearly impos- sible to remove all of them. However, with an integrated approach one can control the size of the population and keep hog damage at
an acceptable level.
Hogs can be controlled with exclusion, snares, live traps, shooting and
aerial hunting. There are no toxicants, repellents, fertility agents or biological control agents registered for use against feral hogs in the U.S. Such products have had limited success in other countries, but the cost of developing and registering them for use in the U.S. has been prohibitive.
In Texas, feral hogs are considered free-ranging exotic animals and may be taken at any time of the year by any legal means. Contact the Texas Parks and Wildlife Department for more information about the legal status of feral hogs. The Texas Animal Health Commission regulates the trapping and moving of feral hogs to help prevent the spread of infectious diseases.
Exclusion
Modifying habitat, changing ani- mal husbandry practices, and building fences are a few of the ways feral hogs can be excluded from an area. However, these methods may be cost prohibitive, especially over large acreages. Fencing small areas may be helpful. Mesh wire fencing used in combination with electric fencing is most successful at excluding hogs. Chain link fencing also can be used if a sufficient portion is buried under- ground. Unfortunately, fencing sel- dom controls hogs permanently. They eventually find their way through most fences, regardless of the design. Also, fences have to be maintained, which increases the cost.
Snares
Snares are excellent tools for man- aging feral hogs. They can be placed on fences where hogs are crossing or along hog trails. A snare consists of a flexible wire cable loop, a sliding lock device, and a heavy swivel. The cable should be either 3/32 or 1/8 inch in diameter and up to 48 inches long.
Snares can be used to capture hogs as they trav- el along trails or under fences.

 
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Most cage traps are constructed of stock panels or heavy, welded wire with a steel pipe or angle iron frame.
Neck snares restrain hogs with a 12- to 18-inch-diameter loop that is secure- ly attached, via the swivel, to a fence or other firm object, or to a drag. An extension cable at least 3 feet long may be needed to reach posts, trees or other stable structures. The snare loop should be suspended above the ground with wire clips or small gauge metal wire. Leg snares also can be used along hog trails. Leg snares, which are placed on the ground, have smaller loops and are activated when an animal triggers the mechanical throwing arm.
Snares have several pros and cons. They are relatively inexpensive, require minimum equipment for installation, and need little maintenance. However, they will catch a variety of animals (including deer), not just hogs. They need to be located where the chance of catching nontarget animals is mini- mized.
Cage Traps
Cage traps are often used with feral hogs and have several advantages. They interfere little with normal hog behavior, can be either permanent or portable fixtures, can catch several hogs at once depending upon the size and design of the trap, and allow the trapper to release any nontarget animals that are caught. Captured hogs can be slaughtered or sent to market. Trapped hogs should not be relocated without checking with the Texas Animal Health Commission for the latest restrictions on relocation. Releasing feral hogs is not recommended because they are destructive and may transmit disease.
Cage traps for feral hogs come in a variety of designs and shapes. Most are constructed of stock panels with a steel pipe or angle iron frame. The pri- mary differences between trap designs are size, portability, door configura- tion, flooring or roofing. Any trap needs two key elements to function prop- erly–a reliable door and stout enough materials to hold trapped hogs. Door

   
There are many kinds of cage traps. The main differences are in size, portability and door configuration. Door designs include drop/slide gates, rooter/lifter gates, and spring/swing gates.
designs include drop gate/slide door, rooter/lifter gates and spring/swing gates. Drop gates use a trip wire to trigger the door. Rooter or lifter gates require that the hog use its nose to lift or root open the door. Spring or swing gates use a screen-door type spring to close the door after hogs push it open. Doors or gates can be hinged from the top or the side of the trap. Some trap designs just use paneling fashioned as a funnel or door into the trap. Doors should open in only one direction so hogs can get in, but not out. Floors and/or roofs can be used on traps to ensure that hogs do not dig underneath, jump out, climb over, or otherwise escape. The most popular styles of cage traps are corral traps, panel traps, box traps and portable traps.
This circular trap has overlapping panels that funnel the hogs into the trap but don't allow them to exit.

  
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Kerrville Hog Rooter Gate Panel

          
Kerrville Hog Rooter Gate

       
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38”
1” Pipe Frame cut on 45
4”x4” Stock Panel, welded to frame
38”
4” 4” 4”
12”
1” tubing, welded to frame
Gate frame 38”x38”
2”x2” angle iron cut on 450
18”
39”
28”
3 4 ”
12 ”
60” to 72”
3/4” tubing
trigger mechanism shown hanging from 2”x2”x4” angle iron brackets which are welded in place
2 gates shown in open position
attach wire to ring on one end and to trip wire on the other end
1 gate shown in closed position

  
Feral hogs can be hunted year-round in Texas. Many hunters use dogs trained to track hogs.
A successful trapping program requires that traps be placed in areas where feral hogs are active and that they be pre-baited for several days to get hogs used to entering the traps. This is accomplished by wiring the door or gate open until hogs are no longer wary of the trap. Hogs can be baited with fermented corn or grain, whole corn, livestock pellets or cubes, vegetables, fruit or carrion. Once hogs are entering the trap without fear, the trap door can be set to capture them. Traps should be checked daily and from a dis- tance when possible. Unnecessary activity around the trap site may cause hogs to avoid it. Be careful when approaching traps that contain hogs as they will become excited. With multi-catch traps, a decoy animal can be left in the trap to help entice other hogs to enter. Decoy animals should be fed and watered daily. Trapping should continue until the desired number of feral hogs has been captured or until no further hog activity occurs at the trap site. Trapping is most successful during cooler months.
Shooting
Hogs can be shot when the opportunity arises, but this usually will not reduce the population to a great extent. Ground shooting might be effective if it is intensive and if the hog population is small. Current Texas law does not require a landowner or landowner's agent or lessee to have a hunting license if feral hogs are damaging the landowner's property. Feral hog hunt- ing has become popular in Texas and generates income for many landown- ers. Feral hog hunting can take place year-round, but most hunters take feral hogs incidental to deer hunting.
Hunting techniques for feral hog are essentially the same as those for white-tailed deer. Stand hunting or still hunting can be conducted in baited areas or in areas with abundant fresh hog sign. As feral hogs are attracted to supplemental feeding sites and deer feeders, these can be prime areas for
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hunting feral hogs. However, feral hogs are very intelligent and can be a challenging foe. Intensive hunting may cause feral hogs to shift their home range or become more nocturnal. When this happens, hogs can be hunted at night using a spotlight with a red filter. Contact the local game warden for permission first, because there are laws regarding the use of a spotlight.
Trained dogs can be used to locate individual hogs or small groups of hogs. In fact, using dogs to trail and bay hogs is a hunting method that has been around for many years. Success will depend on the experience of the dogs and the hunter. Most hunters use tracking dogs to find and bay hogs, while relying on catch dogs to hold hogs once bayed. This method should be used only by skilled hunters with well-trained dogs. Tragically, the major dis- advantage to this technique is that dogs are often injured or killed by hogs.
Aerial Hunting
With proper permits and licenses, aerial hunting is a legal method of controlling feral hogs in Texas. Most aerial hunting is done with helicopters. There must be an experienced pilot and a capable gunner. Aerial hunting can stop a damage problem quickly and is very highly selective because only tar- geted animals are killed. Aerial hunting also can be used in areas that are inaccessible to other management methods. Depending on the amount of damage hogs are causing, the benefits of an aerial hunt can far outweigh the costs (which can be $300 or more per hour flown). Like all other control methods, aerial hunting does have limitations. Rough terrain, poor weather, heavy cover, high cost, and the inherent hazards of low-level flight are all fac- tors to consider.
Summary
Feral hogs are well established in Texas, and because of their adaptabili- ty, reproductive capability, and skill at survival, they are here to stay. The value of feral hogs is a matter of opinion. Landowners suffering
from feral hog damage may be very eager to get rid of them. Hunters look forward to having them show up on their hunting grounds. Entrepreneurs enjoy the economic returns from feral hog hunting fees and the sale of cap- tured hogs. Biologists have ecological concerns as feral swine interact with and harm native wildlife species. Whatever one's opinion may be, the man- agement of feral hogs should be part of any property management plan.
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References
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Choquenot, D. J. McIlroy and T. Korn. 1966. Managing Vertebrate Pests: Feral Pigs. Bureau of Resource Sciences, Australian Government Publishing Service, Canberra.
Conner, S. V. 1971. Texas: a history. AHM Publishing Corp. Arlington Heights, IL.
Fehrenbach, T. R. 1985. Lone star: a history of Texas and the Texans. American Legacy Press. New York, NY.
Haley, J. L. 1985. Texas: from the frontier to spindletop. St. Martin's Press. New York, NY.
SP-18, “Feral Swine: A Compendium for Resource Managers.” Texas Cooperative Extension.H
Schmitz, K. L., editor. 1997. Proceedings: National Feral Swine Symposium. USDA-APHIS-Organizational and Professional Development, Riverdale.
Stevens, R. L. 1996. The Feral Hog in Oklahoma. Samuel Roberts Noble Foundation, Ardmore.
Taylor, R. 1991. The Feral Hog in Texas. Texas Parks and Wildlife Department Federal Aid Report Series Number 28, Austin.
Taylor, R. 1993. Feral Hog Food Habits and Reproduction in the Rio Grande Plains. Texas Parks and Wildlife Department Federal Aid Project Number W-125-R-4, Austin.
L-1925 “Controlling Feral Hog Damage.” Texas Cooperative Extension, Wildlife Services.*
*Extension publications are available from http://tcebookstore.org

https://agrilifecdn.tamu.edu/feralhogs/files/2010/05/B-6149-Feral-Hogs-in-Texas.pdf
                     
26

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They are four-footed eating, breeding, rooting machines.
Feral hogs are an invasive species present in at least 35 states, according to the United States Department of Agriculture. They cause billions of dollars in crop damage each year, and their rooting causes widespread and lasting environmental damage, according to the USDA.
The porcine population bomb is exploding on farms and ranches, timberlands and suburban yards across the country. Sows become sexually mature at six months, and can drop two litters a year. The average litter size is six to 12 piglets. After reaching about two months old, the piglets have no natural predators. Adult hogs have no natural predators, other than man.
Hogs are omnivores, eating just about anything including plants, small animals and carrion.
Sam Upchurch, owner of Grey Rocks Ranch in Autauga County, talks about damage feral hogs inflict on the 5,700 acre ranch.Marty Roney/Advertiser
The problem
Grey Rocks Ranch is a sprawling spread of about 5,700 acres in western Autauga County. Sam Upchurch’s late parents built the ranch into a nationally recognized operation raising Santa Gertrudis cattle. Few cattle are raised here now. The ranch is now intensely managed for wildlife; deer, turkey and quail. The battle against the hogs is an ongoing and aggravating struggle, said Upchurch, an attorney who lives in Birmingham.
“If you don’t eliminate 70 to 80 percent of the population every year, you’re losing ground,” he said. “They are omnivores, they will eat just about anything. And the biggest thing is they destroy the habitat. And I am convinced that habitat is the most important thing for wildlife. Pigs destroy the habitat, they soil, the water and are generally just horrible animals.”
“If you don’t eliminate 70 to 80 percent of the population every year, you’re losing ground.”
SAM UPCHURCH, GREY ROCKS RANCHFor the past two years, the USDA has used helicopters to shoot hogs from the air at Gray Rocks. A gunner uses a semi-automatic 12 ga. shotgun to shoot the hogs. Over a four-day period last year, about 350 hogs we bagged. This year, the effort yielded 74 hogs.
Alabama is a hunting crazy state. Hunting generates an annual economic impact of about $1.8 billion a year in the Heart of Dixie, according to U.S. Department of Fish and Wildlife figures. Whitetail deer are ether most popular game animal in the state, according to the Alabama Department of Conservation and Natural Resources.
Hogs are present in all 67 counties in Alabama, according to the game department. A study conducted by Mississippi State University shows pig populations can double each year. Adult wild hogs eat 3 to 5 percent of their body weight daily, so, 100 hogs can eat 600 pounds of food daily or 110 tons each year.
The study shows there is about a 50 percent overlap in diet for hogs and whitetail deer in the fall, meaning hogs and deer compete for the same food sources. Hogs can live up to 10 years in the wild. When it comes to population control, the study shows that a 50 percent depredation of wild hogs is needed to stop population increases and a 70 percent removal of wild hogs yearly is needed if there is a chance to eventually exterminate the population.
Ty Baker, USDA employee, looks on as a USDA helicopter with a gunman flies over the tree-line during a  feral swine control program at the Grey Rocks Ranch in western Autauga County. (Photo: Albert Cesare/Advertiser)
But the complicating factor is hogs are a mobile scourge, said Mike Blake, ranch manager at Grey Rocks.
“They will move to where the food is,” he said. “So, if your neighbor has hogs, you’ll have hogs eventually. And if you have hogs, your neighbor will have hogs eventually.
“Somebody that has 20 acres out in the country, they are just as proud of their place as Sam is of this place. And hogs will do the same damage on 20 acres that we have seen here. You can’t stop trying to control them, it’s a year-round effort.”
 The MSU study shows that in 2012 in 41 counties in southwest Georgia, wild hog damage totaled $81 million. That breaks down to $57 million in agriculture and $24 million in non-agriculture damage. The damage ranges from row crop destruction to livestock mortality of newborn calves and young sheep and goats. Hogs also cost money in the timber industry, cutting production and impacting reforestation efforts. Then there are water quality issues, where fecal coliform levels increase and water quality decreases. And don’t forget infrastructure damage, the study points out, rooting causes problems in fields, roads and dams and levees.
Agriculture, which includes forestry, is the Number One industry in Alabama, according to the Alabama Farmer’s Federation. The industries drive a $70.4 billion annual economic impact and supply 580,295 jobs, federation figures show.
And don’t forget about the diseases wild hogs can carry. The Centers for Disease Control and Prevention show that feral hogs can carry 45 diseases and parasites that pose a risk to livestock, pets, wildlife — and in some cases — humans. For wildlife and livestock, those diseases include pseudorabies, swine brucellosis, bovine tuberculosis and leptospirosis. Hogs can also carry the foreign animal disease such as African Swine Fever, classical swine fever and foot and mouth disease.  
The MSU study shows that diseases wild pigs carry that can be transmitted to people include leptospirosis, swine brucellosis, e. coli, salmonellosis, toxoplasmosis, trichinosis, giardia and cryptosporidioses.
Clayton Glassey, USDA employee, aids Mike Blake, Grey Rocks Ranch manager, in loading a feral hog into his truck at the Grey Rocks Ranch in western Autauga County. (Photo: Albert Cesare/Advertiser)
The solution
Everyone generally agrees that the best way to control feral hogs is through trapping. Usually the traps are made of metal fence panels and have some type of door that can be tripped to trap the hogs. The most effective practice is to trap an entire group, or sounder, of hogs.
Alabama law forbids the transport of live feral hogs. Once the hogs are trapped, they have to be killed in the trap.
A point of contention among many landowners is the regulation that hogs can’t be hunted at night or over bait during deer season. Deer season runs from mid-October to Feb. 10 in the state. The game department’s logic is simple, the practice of shooting hogs at night and over bait could lead to more night hunting of deer, which is also illegal.
Everyone also generally agrees that controlling hogs isn’t possible one rifle bullet at a time. But still, every method should be used, Blake said.
“That’s a long time, from October to February,” he said. “We trap, hunt with dogs and shoot hogs. We should be able to hunt hogs year-round with little or no restrictions. If somebody is going to night hunt, they are going to night hunt. If your house is infested with roaches or mice, you get rid of them. And hogs are nothing but vermin.”
The no hunting at night over bait during deer season regulation will stand, said Chuck Sykes, director of the game department’s wildlife and freshwater fisheries division.
“Hunting hogs is a recreational activity, it is not an effective management tool,” he said. “Show me a credible study that says hunting is effective, and I’ll reconsider. But I’ve been doing this a long time, I’ve been there and done that. You can’t blow smoke up my skirt and convince me that hunting hogs is an effective tool.
“I’m protecting a $2 billion a year industry here. I’m not going to do anything that threatens the resource.”
“If your house is infested with roaches or mice, you get rid of them. And hogs are nothing but vermin.”
MIKE BLAKE, GREY ROCKS RANCH MANAGERThat approach is “short-sighted,” said Robert White, a Montgomery hunter. He hunts on family-owned land in Lowndes County. Hogs moved onto the place about three years ago.
“We don’t see the deer and turkey we used to see, after the hogs showed up,” he said. “And what really concerns me is we don’t have the deer and turkey on our game cameras like we used to. I’m no wildlife biologist, but I believe the hogs are the reason. If we don’t get a handle on these hogs, we may not have much of a deer population in a few years. The pigs are that big of a problem.”
Clayton Glassey, left, USDA employee, and Ty Baker, USDA employee, take blood samples and DNA from a hog shot from a helicopter during a USDA feral swine control program at the Grey Rocks Ranch in western Autauga County. (Photo: Albert Cesare / Advertiser)
Barry Estes and his brother, Bart, operate Alabama Hog Control Inc. The company sells and leases hog traps, but also takes paid hunters out for hog hunts at night. The two days after deer season ended this year, Barry Estes and clients hunting in Autauga County bagged 40 hogs while hunting at night.
“Hunting is not the most effective way, but it is a control method when you do it right,” Barry Estes said. “We shoot the big hogs, the sows and boars. That means the little hogs may get dumb and walk into those traps that the older hogs kept them out of. You may see those little hogs in the fields in daylight where you can get a shot at them.
“You need to be able to use every tool in the toolbox.”
Other states in the Hog Belt have different laws in dealing with hunting of feral hogs:

• Florida: On private land with landowner permission hogs can be trapped or hunted year-round. No hunting license is required and there is no bag limit. Both sexes may be harvested. A gun and light at night permit is not required to hunt wild hogs for using a gun and light on private land with the landowner’s permission.
• Mississippi: A hunting license is required for residents and non-residents. Landowners and leaseholders, and their designated agents, can hunt nuisance animals year-round at any time day or night. Bait is legal expect during spring turkey hunting season. Bait must be removed at least 10 days before hunting any game animals.
• Georgia: There is no limit and no closed season for feral hogs. Residents must have a valid hunting license unless they are hunting their own property. Non-resident must have a valid hunting license. Feral hogs may be hunted at night with a light which is carried on the person. Hunting over bait is allowed. There is no hunting from vehicles.
• California: A hunting license and wild pig tag are generally required. The season is open year-round and there is no bag limit.

The most effective trapping technique for feral hogs is to capture the whole sounder (family group) at one time, which requires that the pigs become acclimated to the trap and bait inside. 
(Photo: CONTRIBUTED )
A hunting license is required in Alabama for residents to hunt hogs. The exception is if they are hunting on land they own. Non-residents must get a hunting license to hunt hogs. License sales are key to the operation of the department, Sykes said. The wildlife and freshwater fisheries division receive no funding from the state budget. Money to run the division comes from federal taxes levied on the sale of guns and ammunition and hunting and fishing related equipment.
The state receives its portion of the federal money based on the sale of hunting and fishing licenses.
“If we didn’t require licenses to shoot hogs, how many hunting licenses do you think we would sell?” Sykes said. “Deer hunters would just sit on a pile of corn and say they were hog hunting. The only way our guys could build a case is if they saw the hunter dragging a deer out of the woods. And without license sales, we would have to close the doors.”
Back in Lowndes County, White is straight-forward about his hog control methods.
“We’ll trap, but we’ll also shoot every damn hog  get a chance to,” he said. “And we’ll pay the fine if it comes to that.”

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From left, Clayton Glassey, USDA employee, and Ty Baker, USDA employee, gather blood samples and DNA from a hog shot by the USDA from a helicopter as Mike Blake, Grey Rocks Ranch farm manager, ropes the hog.(Photo: Albert Cesare / Advertiser)
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Tourists looking for ever more thrilling holidays are taking to the skies above Texas to shoot wild hogs as part of the state’s effort to limit the spread of an invasive species that annually causes millions of dollars in damage to farmland and livestock nationally. 
For up to $50,000, people can hunt the feral hogs from a helicopter and even use a machine gun to mow them down. 
“There’s only so many places in the world you can shoot machine guns out of a helicopter and no one shoots back,” said Chris Britt, co-owner of HeliBacon, one of the companies offering the aerial hog hunts. 
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There were 2,752 helicopter hog hunts in Texas last year, up 81 percent from 2011, according to Texas Parks and Wildlife Department data. About 34,400 hogs were killed in those hunts, up 53 percent. 
The total U.S. population of the hogs is estimated at more than 6 million, and state and federal government officials are increasing efforts to rid themselves of the pesky animals. 
There are nearly 150 companies and individuals permitted to hunt invasive feral hogs from helicopters as part of the Texas’ so-called pork chopper bill passed in 2011. State legislators last month sent a bill to Governor Greg Abbott that would allow hog hunting from hot air balloons. 


Animals rights activists are not fans. 
“The Humane Society of the United States opposes the use of aerial gunning – whether from a helicopter or a hot air balloon – as a means of resolving conflicts with wildlife populations because it is unnecessarily cruel, dangerous and costly compared to other wild pig control methods,” said Samantha Hagio, a director at the agency. 
Slideshow (4 Images)However, aerial hunting is one of the most effective ways to eradicate hogs in open areas such as Texas fields of corn and rice that are destroyed, said Jack Mayer, manager of environmental sciences at Georgia’s Savannah River Laboratory and author of “Wild Pigs in the United States.” 
Even so, hunting and trapping are not keeping up with the rate of breeding and the feral herd continues to grow. 
“You are not even stemming the tide,” Mayer said by phone. 
Wild boars were brought to Texas and released for hunting in the 1930s. They bred with free-ranging domestic animals and escapees that had adapted to the wild, according to the Smithsonian. Since hogs, wild or otherwise, are not native to the United States, they have no predators and proliferated across Texas and other states. 
About $25.55 million was appropriated this year to the U.S. Department of Agriculture to tackle feral hogs on the national level and the agency is testing unmanned drones to track the hogs that thrive in swamps and forests, said Dale Nolte, the USDA’s feral swine program manager. 
Trump backs off emergency order to end shutdownHelicopter hunting already is allowed in Louisiana and Oklahoma legislators are considering a bill that would permit aerial hunts there. 
Hot air balloons could allow hunters to approach hogs more quietly than a helicopter or give shooters a steadier shot, Mayer said. 
In South Carolina, where aerial hog hunting is not permitted, farmer Rusty Kinard pays a local hunter $25 for each hog killed on his land. Still, there are hundreds near his fields and the hogs ate through nearly 30 acres (12 hectares) of peanuts last month. 
“We will kill them suckers, every one we can,” he said. 
Reporting by Michael Hirtzer in Chicago; Editing by Marguerita Choy

Our Standards:The Thomson Reuters Trust Principles.

The Texas House gave a final OK today to the "pork chopper" bill and sent it off to the governor's office. The bill would allow licensed hunters to hire helicopters and contract with landowners to shoot feral hogs and coyotes on their property from the sky. 
BY BRANDI GRISSOM AND BECCA AARONSON MAY 17, 20115 PM

REPUBLISH
James Stone's ranch outside of Lockhart on May 10, 2011. Hogs have hobbled Stone's property, ruining pasture land, killing trees and damaging fences. He estimates taking out over 500 hogs during the last three years.  Spencer SelvidgeThe Texas House gave a final OK today to the "pork chopper" bill and sent it off to the governor's office. The bill would allow licensed hunters to hire helicopters and contract with landowners to shoot feral hogs and coyotes on their property from the sky. The Senate approved the measure last week but changed the wording of the bill slightly to give the Texas Parks and Wildlife Department more authority to regulate who can pay for helicopter hunts. 
State Rep. Marc Veasey, D-Fort Worth, said feral hogs are becoming problematic even in urban areas like the one he represents, and asked whether feral hogs had any natural predators. 
Rep. Sid Miller, R-Stephenville, the author of bill, said no. "Man is the biggest predator, and I'm trying to increase that predation through this bill," Miller said. 
The bill passed with a vote of 141-1, and is now headed to Gov. Rick Perry's desk. The only vote against the measure came from Rep. Eddie Lucio III, D-Brownsville.

​By: Josh Helcel, Extension Associate
Texas A&M Natural Resources Institute

Wild pigs (Sus scrofa) are notorious for their ability to learn from past experiences and evade control efforts.  Groups of wild pigs that are not pressured often increase their diurnal activity and become more active during the day time (Gundlach 1967).  However, as abatement pressures increase wild pigs can alter their behavior to become more active at night and other behaviors can modify as well (Stegeman 1938, Hanson and Karstad 1959, Choquenot et al. 1996, Waithman 2001, Pei 2006).  This article will discuss various effects abatement techniques can have on wild pigs, and will recommend strategies that can help to minimize behaviors including trap aversion and escape when enacting control efforts for wild pigs.

Hunting Can Accelerate Wild Pig Birth Rates
It is accepted that sport hunting wild pigs alone will not significantly reduce populations.  Perhaps less apparent is that human activities such as hunting can influence evolutionary characteristics at both the population and species level (Darimont et al. 2009).  A good example of this has been observed in deer species (Odocoileus sp.); whereas high rates of trophy harvest were shown to lead to smaller overall horn size and body mass over time (Coltman et al. 2003).  In wild pig populations, however, high hunting pressure doesn’t necessarily lead to reduced body sizes or smaller tusks.  Extensive monitoring of wild pig populations over 22 years found that high hunting pressure can actually cause wild pigs to shorten their gestation period by as much as 12 days per cycle (Gamelon et al. 2011).  This acceleration is further compounded by increased conception rates of sows within their first year of life when populations are subjected to intense hunting or other abatement pressures (Gamelon et al. 2011).  Essentially, wild pigs may breed earlier and produce offspring more quickly when subjected to hunting pressure.  Given this novel survival strategy, it becomes more understandable why a state like Missouri banned completely the sport hunting of wild pigs on conservation lands.

 

Research indicated that wild pig sows subjected to high hunting pressure had higher conception rates in their first year and produced offspring up to 12 days sooner than normal gestation.
Wild Pig Adaptations to Aerial Gunning
Aerial gunning is an effective population reduction strategy unless limited by topography or dense canopy cover (Campbell et al. 2010).  However, previous research has shown that wild pigs can intelligently adapt their behavior to avoid detection and flushing by helicopters (Saunders and Bryant 1988).  It might be assumed that these animals would simply disperse from their home range in response to aerial gunning efforts.  In fact, research indicated the opposite in that core area and home range sizes did not alter either before or after enacting aerial control (Campbell et al. 2010).  Rather, wild pigs can adapt to aerial gunning by seeking dense cover and refusing to flush from it despite concerted efforts by the pilot and crew.  



Instead of flushing, some wild pigs have adapted to evade helicopters by holding within dense cover. 
 
What is significant about this behavior is that until relatively recently wild pig populations had not encountered significant predation from above their line of sight.  Despite this, they have quickly adapted to be capable of intelligently evading a formidable 5000 pound “aerial predator” that otherwise would seem to have every advantage.  The intelligence and adaptability of wild pigs are key factors that compound effective control (Sweeney et al. 2003), and this is again evidenced by their potential to evade aerial gunning efforts.

Trap Aversion
Research has long documented trapping as an effective population reduction technique, with 70-80% reductions in populations having been reported using this technique alone (Saunders et al. 1990, Vernes et al. 1999).  However, wild pigs can adapt to avoid traps altogether for a variety of reasons.  This can occur due to the size and type of trap used, but also can be attributed to inadvertently “educating” wild pigs through incomplete captures.  With the exception of solitary adult males (boars), wild pigs travel in social groups called sounders.  When trapping these animals, it is important to target and remove the entire sounder in a single trapping effort.  This is generally accomplished through a process of pre-baiting and conditioning the group over time to routinely enter a trap large enough to contain the entire sounder.  Corral style traps are often best suited for this, and research indicated this type of trap to be four times more effective than conventional box traps (Williams et al. 2010).  Box traps, while valued for their portability, usually only capture 1-3 animals at a time.  No matter what type of trap is used, incomplete captures can divide sounders and cause remaining pigs to avoid traps in the future. 


In order to minimize learned trap aversion due to incomplete captures, the goal of any trapping effort should be to target and remove the entire sounder of wild pigs.
Trap Escape
Wild pigs can also adapt to escape traps, and individuals that learn to do so often exhibit this behavior repeatedly.  Trap escapes can be accomplished through climbing, rooting, exploiting trap design flaws and even jumping considerable heights in excess of 4 feet.  It is important to construct and implement sound trap designs, and it is equally important to check traps as soon as possible following each trap night.  Many experienced trappers check their traps at first light and bring a firearm in order to harvest any residual pigs that may be near the trap site due to incomplete capture or escape.  The Texas A&M Natural Resources Institute recommends that corral traps be constructed with four to six 16’ cattle panels that have 5’ panel height and 4” mesh in order to minimize trap escapes.  It is generally not necessary to bury or trench paneling underground, but it is important not to leave any gaps at ground level or near the head gate.  Game cameras can be integral in monitoring wild pig activity at trap sites, and can also help to identify any modifications necessary in order to minimize the potential for trap escape.



Wild pigs will attempt to escape traps if given the opportunity. Ensure that traps are constructed properly and check traps at first light to help minimize trap escape attempts. (Image Credit: Andy James)

Conclusion
Wild pigs exhibit a variety of behavioral responses to abatement pressure.  Their intelligence and adaptability can complicate effective control, factors that are only compounded by their extreme fecundity.  It is important to select appropriate strategies as well as to adapt control techniques as necessary in order to minimize any potential issues which can reduce the success of abatement efforts.  This can undoubtedly be easier said than done, as is evidenced by the numerous and often remarkable ways in which wild pigs can evade control efforts despite the best technologies available to man.  However, best management practices including trapping, aerial gunning, strategic shooting, snaring, and the use of trained dogs remain proven tools that, when implemented in a combined approach, can successfully abate the damages associated with wild pigs.
 
Wild Pig Resources Listed Below are Available at the AgriLife Bookstore
 
– L-5523 Recognizing Feral Hog Sign– L-5524 Corral Traps for Capturing Feral Hogs
– L-5525 Box Traps for Capturing Feral Hogs
– L-5526 Placing and Baiting Feral Hog Traps
– L-5527 Door Modifications for Feral Hog Traps
– L-5528 Snaring Feral Hog
– L-5529 Making a Feral Hog Snare
– SP-419 Feral Hogs Impact Ground-nesting Birds
– SP-420 Feral Hog Laws and Regulations
– SP-421 Feral Hogs and Disease Concerns
– SP-422 Feral Hogs and Water Quality in Plum Creek
– SP-423 Feral Hog Transportation Regulations
– L-5533 Using Fences to Exclude Feral Hogs from Wildlife Feeding Stations
– WF-030 Reducing Non-target Species Interference While Trapping Wild Pigs
– ENRI-005 Wild Pigs Negatively Impact Water Quality: Implications for Land and Watershed Management
 
Click here for additional resources on wild pigs
 
_______________________________________________________________________________________


For educational programming or technical assistance with wild pigs please contact:
Josh Helcel, 512-554-3785, josh.helcel@tamu.edu
  
Literature Cited
Campbell, T.A., D.B. Long and B.R. Leland. 2010. Feral swine behavior relative to aerial gunning in southern Texas. Journal of Wildlife Management 74(2):337-341.
Coltman, D. W., P. O'Donoghue, J. T. Jorgenson, J. T. Hogg, C. Strobeck, and M. Festa-Bianchet. 2003. Undesirable evolutionary consequences of trophy hunting. Nature 426:655-658.
Choquenot, D., J. McIlroy, and T. Korn. 1996. Managing vertebrate pests: Feral pigs. Bureau of Rural Sciences, Australian Government Publishing Service, Canberra, Australia.
Darimont, C. T., S. M. Carlson, M. T. Kinnison, P. C. Paquet, T. E. Reimchen, and C. C. Wilmers. 2009. Human predators outpace other agents of trait change in the wild. Proc. Natl. Acad. Sci. USA 106:952-954.
Gamelon, M., A. Besnard, J. Gaillard, S. Servanty, E. Baubet, S. Brandt and O. Glmenez. 2011. High hunting pressure selects for earlier birth date: wild boar as a case study. Evolution 65(11):3100-3112.
Gundlach, H. 1968. Brutfursorge, Brutpflege Verhaltensontogenese und Tagesperiodik beim Europaischen Wildschwein (Sus scrofa L.). Zeitschrift fur Tierpsychologie, 25(8):955-995.
Hanson, R. P., and L. Karstad. 1959. Feral swine in the southeastern United States. Journal of Wildlife Management 23(1):64-74.
Pei, K. J. C. 2006. Present status of the Formosan wild boar (Sus scrofa taivanus) in the Kenting National Park, southern Taiwan. Suiform Soundings 6(1):9-10.
Saunders, G., and H. Bryant. 1988. The evaluation of feral pig eradication program during simulated exotic disease outbreak. Australian Wildlife Research 15:73-81.
Saunders, G., B. Kay, and R. Parker. 1990. Evaluation of a warfarin poisoning programme for feral pigs (Sus scrofa). Australian Wildlife Research 17(5):525-533.
Stegeman, L. J. 1938. The European wild boar in the Cherokee National Forest, Tennessee. Journal of Mammalogy 19(3):279-290.
Sweeney, J. R., J. M. Sweeney, and S. W. Sweeney. 2003. Feral hog. In ‘wild mammals of North America’. Johns Hopkins University Press: Baltimore, MD. pp. 1164–1179.
Vernes, K., C. N. Johnson and J. Mitchell. 1999. The effectiveness of trapping in reducing pig abundance in the Wet Tropics of north Queensland. In ‘Feral pigs: Pest status and prospects for control. Pp 51-56. Proceedings of a feral pig workshop. James Cook University, Cairns, March. Research Report No. 13. Cooperative Research Centre for Tropical Rainforest Ecology and Management, Cairns, Australia.
Waithman, J. 2001. Guide to hunting wild pigs in California. California Department of Fish and Game, Wildlife Programs Branch, Sacramento, California.
Williams, B. L., R. W. Holtfreter, S. S. Ditchkoff and J.B. Grand. 2010. Trap style influences wild pig behavior and trapping success. Journal ofWildlife Management 75(2):432–436.
 

Posted 30th May 2018 by Wildlife and Fisheries Extension
Labels: adaptability aerial gunning Box Trap Corral Trap Feral Hog head gate hog hunting intelligence reproduction Sus scrofa Trap Aversion Trap Avoidance Trap escape Wild Pigs
  

​By: Forrest Cobb, Research Assistant
Texas A&M Natural Resources Institute
 

 
  
Three years ago some of my colleagues and I spent every week checking and rechecking an electric fence we hoped would keep wild pigs out.  We were conducting a horticultural study with 1,600 fresh and tender ornamental plants grown over the course of a year.  Unfortunately for us, our small plot was not far from a creek that supported a seemingly endless population of wild pigs.  Every week we would see damaged brush, dead plants, and clumps of bare loose soil just outside the fence line.  Thankfully they never got inside, but while we had the luxury of fencing off and maintaining that relatively small enclosure, that same level of exclusion would not have been feasible for a larger tract of land and certainly is not for stream and rivers courses and their associated wetlands.  Impacts on agriculture, plant diversity, and wildlife habitat can be easily observed in areas disturbed by the rooting behavior of wild pigs.  One of their less obvious impacts, and the focus of our newest publication, is their impact on water quality in Texas.  But before we discuss some of these impacts, let's consider just how serious of an issue wild pigs have become.
 
Wild pigs now occur in at least 36 states and the economic toll of these animals in the US was estimated to exceed $1.5 billion in 2007, a number likely to be much larger today.  Population modeling indicates that as many as 3-5 million wild pigs now inhabit Texas and they are present in almost every county in the state (Figure 1).  The number and range of these animals is not surprising considering their incredible adaptability and fecundity.  With an average lifespan of 4-5 years, adult sows commonly produce litters of 4-6 offspring and can have 1-3 liters per year.  Their population growth is relatively unchecked by predators.  Coyotes, bobcats, and feral dogs have been known to prey upon juveniles but humans remain the only significant predators of adult wild pigs.  Population modeling has indicated that as much as 66% of the wild pig population would need to be harvested every year for 5 years or more to halt population growth.  With humans only harvesting an estimated 29% of the population per year, we will see continued growth and spread of wild pigs.  Omnivorous and intelligent, wild pigs are well adapted to conditions across the state and their foraging, opportunistic predation, rooting, and wallowing behaviors are incredibly disruptive, having serious repercussions for the ecological and economic health of our state.

 

Figure 1.  NMFSS data showing 2016 feral swine populations by county. (Image Credit – USDA-APHIS)
 
 
A worrisome aspect of wild pigs in Texas is the impact on water quality they have by damaging riparian areas and wetlands.  Since wild pigs lack sweat glands, they often stay close to water bodies in order to cool themselves by wallowing in wet, shaded areas. This concentrates wild pig populations in sensitive riparian areas, which are both crucial transitional zones between upland areas and water bodies, and a vital component of maintaining overall water quality.  Healthy riparian and wetland communities perform numerous critical functions which maintain water quality including, stabilizing soils, decreasing water velocities during flooding, providing fish and wildlife habitat, mitigating contamination from surrounding storm water runoff, and lowering water temperatures through shading.  Because of their disruptive rooting and wallowing behavior, as well as heavy foraging of native mast (fruits and nuts), wild pigs can significantly decrease native vegetation cover in riparian corridors.  By reducing native ground cover, native tree abundance, and native seedling establishment, they increase the presence and abundance of invasive plant species, and destabilize stream and river banks leading to increased sedimentation, nutrient loads, turbidity, and altered pH levels.
 
While they indirectly impact water quality through the destruction of riparian and wetland communities, wild pigs also directly impact water quality through defecation.  One study of fecal coliforms in the Buck Creek watershed of Texas found that as much as 50% of E.coli bacteria samples collected were from wildlife sources including wild pigs, while only 20% originated from domestic animals or livestock.  With a high defecation rate (1,121 grams per day) when compared to other wildlife species like white-tailed deer (500-772 grams per day), their contribution to bacterial loading and water quality is becoming a growing concern for land managers and regulatory authorities statewide.  Especially since, as of 2012, the majority of Texas water bodies were listed as bacterially impaired.  Bacterial impairment increases the potential for disease transmission in both wildlife and human populations.  Recreational activities such as swimming, wading, and fishing are necessarily restricted as a result of these unsanitary conditions.  
 
 

 Wild pig activity in and near water sources can spread invasive plant species, destabilize soil, reduce native species abundance, alter nutrient and pH levels, increase turbidity, and contribute to increased E. coli bacteria levels in surface water systems.
 
 
Agriculture is also impacted when access to high quality water becomes limited.  One study found that livestock with a quality water supply can produce as much as 20% more animal gain as compared to livestock with access to impaired water.  Furthermore, the low dissolved oxygen and high nutrient levels associated with impairment can reduce aquatic species abundance and diversity, and lead to massive algal blooms and fish kills. 
 
Wild pig populations contribute to impaired water quality in Texas, both directly through fecal deposition, and indirectly by altering wetland and riparian communities.  While more research is needed to quantify their impact and contribution to water impairment, wild pig abatement has been shown to benefit riparian ecosystems and overall water quality by reducing bacterial impairment, reducing the spread of invasive species, increasing vegetation cover, facilitating proper nutrient cycling, decreasing erosion, and decreasing surface water turbidity.  Given the wide spread and growing challenge posed by wild pigs in Texas, the potential benefits of management and control should be considered in any plan for improving or safeguarding water quality.  Application of consistent and widespread abatement efforts remains the only way of stabilizing and thus reducing the impacts of wild pig populations on landscapes and water quality in Texas.  
 
For more information on how wild pigs negatively impact water quality, please click the link below to download a free electronic copy of “Wild pigs negatively impact water quality: Implications for land and watershed management” from the AgriLife Bookstore.
  
http://www.agrilifebookstore.org/Wild-Pigs-Negatively-Impact-Water-Quality-p/enri-005.htm
  
Wild pig resources listed below are available at the AgriLife Bookstore
– L-5523 Recognizing Feral Hog Sign
– L-5524 Corral Traps for Capturing Feral Hogs
– L-5525 Box Traps for Capturing Feral Hogs
– L-5526 Placing and Baiting Feral Hog Traps
– L-5527 Door Modifications for Feral Hog Traps
– L-5528 Snaring Feral Hog
– L-5529 Making a Feral Hog Snare
– SP-419 Feral Hogs Impact Ground-nesting Birds
– SP-420 Feral Hog Laws and Regulations
– SP-421 Feral Hogs and Disease Concerns
– SP-422 Feral Hogs and Water Quality in Plum Creek
– SP-423 Feral Hog Transportation Regulations
– L-5533 Using Fences to Exclude Feral Hogs from Wildlife Feeding Stations
– WF-030 Reducing Non-target Species Interference While Trapping Wild Pigs
– WF-033 Wild Pigs and Ticks: Implications for Livestock Production, Human and Animal Health
– ENRI-005 Wild Pigs Negatively Impact Water Quality: Implications for Land and Watershed Management
 

Click here for additional resources on wild pigs

_______________________________________________________________________________________

For educational programming or technical assistance with wild pigs please contact:
Josh Helcel, 512-554-3785, josh.helcel@tamu.edu
 
References
Baird, J.V. 1990. Soil facts: Nitrogen management and water quality. North Carolina Cooperative Extension AG-439-2.
Campbell, T.A. and D.B. Long. 2009. Feral swine damage and damage management in forested ecosystems. Forest Ecology and Management 257:2319-2326.
Chavarria, P.M., R.R. Lopez, G. Browser, and N.J. Silvy. 2007. A landscape-level survey of feral hog impacts to natural resources of the Big Thicket National Preserve. Human Wildlife Conflicts 1:199-204.
Cushman, J.H., T.A. Tierney, and J.M. Hinds. 2004. Variable effects of feral pig disturbances on native and exotic plants in a California grassland. Ecological Applications 14:1746–1756.
Doupe´ R.G., J. Mitchell, M.J. Knott, A.M. Davis, and A.J. Lymbery. 2009. Efficacy of exclusion fencing to protect ephemeral floodplain lagoon habitats from feral pigs (Sus scrofa). Wetlands Ecology and Management. DOI 10.1007/s11273-009-9149-3
Gingerich, J.L. 1994. Florida’s Fabulous Mammals. World Publications. Tampa Bay.
Giovanni, G. D., L. Gregory, P. Dyer, and K. Wagner. 2007. Bacterial Monitoring for the Buck Creek Watershed – Final Report. Texas AgriLife Research, Texas Water Resources Institute, and Texas AgriLife Extension Service. TSSWCB Project 03-07.
Jay, M.T., Cooley, M., Carychao, D., Wiscomb, G.W., Sweitzer, R.A., Crawford-Miksza, L., Farrar, J.A., Lau, D.K., O’Connell, J., Millington, A., Asmundson, R.V., Atwill, E.R., and Mandrell, R.E. 2007. Escherichia coli O157:H7 in feral swine near spinach fields and cattle, central California coast. Emerging Infectious Diseases 13:1908–1911.
Kotanen, P.M. 1995. Responses of vegetation to a changing regime of disturbance: Effects of feral pigs in a California coastal prairie. Ecography 18:190-199.
Mapston, M. E. 2007. Feral hogs in Texas. AgriLife Extension B-6149 03-07, Texas A&M University, College Station, USA.
Naiman, R.J., H. Decamps, and M.E. McClain. 2005. Riparian: ecology, conservation and management of streamside communities. Elsevier, San Diego, USA.
Ohio State University Extension. 2006. Ohio livestock manure management guide. Bulletin 604. The Ohio State University, Columbus, USA.
Parker, I.D. 2010. The role of free-ranging mammals in the deposition of Escherichia coli into a Texas floodplain. Doctoral Dissertation. Texas A&M University, College Station, TX.
Pimental, D. 2007. Environmental and economic costs of vertebrate species invasions into the United States. Managing Vertebrate Invasive Species. College of Agriculture and Life Sciences, Cornell University, Ithaca, New York, USA.
Siemann, E., J.A. Carrillo, C.A. Gabler, R. Zipp, and W.E. Rogers. 2009. Experimental test of the impacts of feral hogs on forest dynamics and processes in the southeastern US. Forest Ecology and Management 258:546-553.
Singer, F.J., W.T Swank, and E.E.C. Clebsch. 1984. Effects of wild pig rooting in a deciduous forest. Journal of Wildlife Management 48:464-473.
Taylor, R.B., E.C. Hellgren, T.M. Gabor, and L. Ilse. 1998. Reproduction of feral pigs in southern Texas. Journal of Mammalogy 79:1325–1331.
Texas Commission on Environmental Quality (TCEQ). 2013. 2012 Texas Integrated Report of Surface Water Quality for Clean Water Act Sections 305(b) and 303(d).
Timmons, J.B., J. Mellish, B. Higginbotham, J. Griffin, R. Lopez, A. Sumrall, K. Skow, and J.C. Cathey. 2012. Feral hog population growth, density and harvest in Texas. Texas A&M AgriLife Extension Service SP-472.
Williams, W.D., O. Kenzie, D. Quinton, and P. Wallis. 1996. The water source as a factor affecting livestock production. In: Animal Science research Development: Meeting Future challenges. Proceedings, Can. Soc. Anim. Sci., Lethbridge, AB. E

Posted 5th June 2018 by Wildlife and Fisheries Extension
Labels: aerial gunning bacterial source tracking Biology Distribution E. coli Feral Hogs Harvest Hunting Impaired watersPublication Riparian Sus scrofa Trapping water quality concerns Wetlands Wild Pigs
  

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Written by Shelby McCay, Texas A&M University, WFSC ’15 and MNRD ’19
Edited by Josh Helcel, Extension Associate, Texas A&M Natural Resources Institute

Wallowing is defined as coating the body surface with mud or a mud-like substance and while this behavior is not found exclusively in wild pigs (Sus scrofa) (rhinos, elephants, bovids and deer will also wallow) it is most commonly attributed to them (Bracke 2011). You may be wondering, why do they wallow?  What function does it serve?  As it turns out there are a variety of reasons why pigs wallow and we will explore each further here.
Thermoregulation
Both wild and domestic pigs are prone to overheating due to their lack of sweat glands and so they must use other methods to regulate their body temperature. These include moving during the cooler hours of the day, occupying shaded areas, or wallowing.  In Texas, wild pigs typically wallow during mid-day throughout the summer and into the early fall months in order to avoid the hottest parts of the day.  As average temperatures begin to decline, wallowing becomes less of a necessity for cooling and more of an opportunistic behavior.  So why do they use mud to cool off instead of just getting directly in water?  One study showed that it took two hours for the water in the mud on wild pigs to evaporate compared to only 15 minutes for just water (Ingram 1965).  Essentially, layers of mud can serve as a kind of long lasting “wet suit” to keep wild pigs cool in warm environments (Bracke 2011).

Health Benefits
In addition to aiding in thermoregulation, the mud layer wild pigs obtain from wallowing can provide multiple health benefits. Research has shown that mud can serve as a kind of protective layer against biting insects (Nalin 1996) and sunburn (Gegner 2001). One study found that wallowing could potentially help wild boars disinfect wounds caused by fighting through the bactericidal properties of the mud (Fernández-Llario 2005). Wild pigs can carry a variety of ectoparasites, including fleas, lice and ticks (Schuster 2011) and they usually carry the highest parasite load in the summer months (Bracke 2011).  Ticks in particular are commonly found behind the ears and on thin skinned areas where wild pigs have a hard time reaching (Bracke 2011) and are one of the most common ectoparasites found on wild pigs.  In a study conducted in Texas, seven different species of ticks were found on wild pigs across eight eco-regions (Sanders et al. 2013).  Wallowing can help wild pigs to remove some of these ectoparasites as the mud layer can trap some of them and the pigs can later remove by rubbing on either natural or manmade objects. Wild pigs will often intelligently seek out telephone poles and posts treated with creosote achieve this, as the compound is toxic to ectoparasites.  In areas with high wild pig activity, visible markings from their rubbing behavior can often be found. 


Wallowing and rubbing behavior helps to rid wild pigs of fleas, lice and ticks.

Sexual Function
In a 2005 study, Fernàndez-Llario looked at the wallowing behavior of wild boars in Spain and found that males wallowed mainly in the autumn months when temperatures and parasitic loads were low.  So if thermoregulation and parasite removal weren’t driving the wallowing behavior in the males, what was? To try to figure this out, the study also looked at the reproductive systems of sows and found that the primary breeding season stretched from the last part of October into the first part of November which overlapped with the increased wallowing behavior in the males. This suggests that there may also be a sexual function to wallowing for wild pigs, although further studies are needed to confirm this potential connection.


Research indicated that wallowing may also serve a role in wild pig reproduction. While more research is needed, adult males (boars) increased wallowing activity during active breeding periods.

Conclusion
Overall wallowing is unique behavior that serves many functions for wild pigs, but it does have negative environmental impacts on our Texas’s water systems.  Wallows can affect watersheds by muddying waters, creating bank erosion, creating algae blooms, destroying aquatic vegetation, and decreasing livestock use and fish production (Stevens 2010, eXtension 2012, Helcel et al. 2018).  Wild pigs will often create wallows in moist areas near ponds, creeks and sloughs since they offer easy access to mud and as they lie in these areas they will defecate, adding bacteria and pathogens into the water resulting in impairments to the system and degrading the ecosystem (Peterson et al. 2012, Helcel et al. 2018).  This fecal contamination can transmit pathogens that can threaten agricultural production, livestock productivity, wildlife, and limit human use (Helcel et al. 2018).  Consistent and widespread abatement efforts remain important in reducing the damages associated with wild pigs, and can lead to  improved water quality, habitat and overall ecosystem functionality. 
Wild pig resources listed below are available at the AgriLife Bookstore
– L-5523 Recognizing Feral Hog Sign
– L-5524 Corral Traps for Capturing Feral Hogs
– L-5525 Box Traps for Capturing Feral Hogs
– L-5526 Placing and Baiting Feral Hog Traps
– L-5527 Door Modifications for Feral Hog Traps
– L-5528 Snaring Feral Hog
– L-5529 Making a Feral Hog Snare
– SP-419 Feral Hogs Impact Ground-nesting Birds
– SP-420 Feral Hog Laws and Regulations
– SP-421 Feral Hogs and Disease Concerns
– SP-422 Feral Hogs and Water Quality in Plum Creek
– SP-423 Feral Hog Transportation Regulations
– L-5533 Using Fences to Exclude Feral Hogs from Wildlife Feeding Stations
– WF-030 Reducing Non-target Species Interference While Trapping Wild Pigs
– WF-033 Wild Pigs and Ticks: Implications for Livestock Production, Human and Animal Health
– ENRI-005 Wild Pigs Negatively Impact Water Quality: Implications for Land and Watershed Management


Click here for additional resources on wild pigs

______________________________________________________________________________________________

For educational programming or technical assistance with wild pigs please contact:
Josh Helcel, 512-554-3785, josh.helcel@tamu.edu


References
Bracke, M.B.M. 2011. Review of wallowing in pigs: Description of the behaviour and its motivational basis. Applied Animal Behavior Science 132, 1-13. 
eXtension. 2012. Feral Hog Behavior. http://articles.extension.org/pages/64381/feral-hog-behavior.
Fernández-Llario, P., 2005. The sexual function of wallowing in male wild boar (Sus scrofa). Journal of Ethology. 23, 9–14.
Ingram, D.L., 1965. Evaporative cooling in pig. Nature 207, 415–416.
Gegner, L., 2001. Considerations in organic hog production. ATTRA’s organic matters series. http://www.organicagcentre.ca/Docs/ ATTRA/hog production2001.pdf. 
Helcel, J., Teel, P., Tyson, M., Cash, J., Hensley, T., and Cathey, J.C. 2016. Wild Pigs and Ticks: Implications for Livestock Production, Human and Animal Health. AgriLife Extension Service. https://wildpigs.nri.tamu.edu/media/1293/ewf-033-widl-pigs-and-ticks-implications-for-livestock-production-human-and-animal-health.pdf.
Helcel, J., Cobb, F. and Cathey, J. 2018. Wild pigs negatively impact water quality: Implications for land and watershed management. AgriLife Extension Service. https://wildpigs.nri.tamu.edu/media/1187/enri-005-widl-pigs-negatively-impact-water-quality-implications-for-land-and-watershed-management.pdf.
Nalin, D.R., 1996. O come, let us wallow in glorious mud’ Transactions of the Royal Society of Tropical Medicine and Hygiene, 90, p. 717.
Peterson, J., Cathey, J., Wagner, K. and Redmon, L. Lone Star Healthy Streams Feral Hog Manual. Texas A&M AgriLife Extension. http://www.agrilifebookstore.org/Lone-Star-Healthy-Streams-Feral-Hog-Manual-p/esc-005.htm.
Sanders, D.M., A.L. Schuster, P. W. McCardle, O. F. Strey, T. L. Blankenship, and P. D. Teel. 2013. Ixodid ticks associated with feral swine in Texas. Journal of Vector Ecology. 38:361–373.
Stevens, R.  2010.  The feral hog in Oklahoma. The Samuels Roberts Noble Foundation, Ardmore, Oklahoma, USA.  
Schuster, A.L. 2011. Spatial and Temporal Survey of Feral Pig Ectoparasites in Three Texas Wildlife Districts (Doctoral Dissertation). 
http://oaktrust.library.tamu.edu/bitstream/handle/1969.1/ETD-TAMU-2011-12-10290/SCHUSTER-DISSERTATION.pdf;sequence=2. 


Posted 28th September 2018 by Josh Helcel
Labels: A&M adaptability AgriLife bacteria cooling Feral Hogs fleas impairment lice reproduction Riparian rub Sus scrofa tamu thermoregulation Ticks wallowing water quality Wild Pigs