Issue of the Week: Feral Swine Populations on the Rise


Domesticated pigs, or swine, were introduced to North America as a meat source for early settlers. While some pigs escaped their confines, others were released by earlier explorers to be a wandering food source. Either way, pigs began to establish populations and revert to a “wild” state, deemed as feral.

Pigs are highly intelligent and are able to reproduce quickly. Some say they are among the most fertile mammals on earth, having an average of 5-6 piglets once or twice a year. This enables their populations to quickly expand.  Today, most experts would agree that there is somewhere between 4 million and 8 million feral pigs throughout the U.S.

Texas is one of the most severely impacted states.  Feral hogs are a nuisance with an estimated 2.6 million hogs in the state and still growing. Recent studies, estimate that annual population growth in Texas is approximately 18-21%. At that rate (if left unchecked), the population would take about 5 years to double in size.

Feral swine can host many parasites and diseases that threaten humans, livestock and other wildlife. Also, they can cause extensive damage to forests, agricultural lands and water sources. They often trample and eat crops and even prey on small livestock such as lambs or claves. A 2004 survey conducted by Texas A&M AgriLife Extension Service placed annual damage to agriculture in Texas alone at $52 million with an additional $7 million spent by landowners to attempt to control the pigs or correct the damage. They often reside in large areas and use creeks for water sources. Their water activities cause extreme erosion to creeks, streams, ponds and lakes, and their presence can cause contamination to water sources.


2009 Feral Swine Population Distribution

Feral swine compete for food and space with other animals such as turkey or deer and can vastly decrease the presence of these game species due to the swine’s overwhelming numbers. Additionally, feral swine are incredibly resourceful and will often search for pet food left out overnight causing more hogs to reside in developed areas.

“With the population going the way it is, it’s been getting out of hand. If you don’t have a problem with hogs, chances are it’s just a matter of time,” extension agent for agriculture Michael Heimer said. “We’ve had problems where pets disappear too. They are dangerous. Hunters would have to remove 70 percent of the population this year to maintain a static population.”

Nonlethal and lethal measures have been used to dispose states of their feral hog problems. Hunting and trapping are the most common in overpopulated areas. For example, Texas estimates they remove 753,646 wild pigs each year.  Fencing systems are being developed to separate hog populations from farms and livestock to minimize damage. Other nonlethal methods, such as vaccination, are extremely expensive and sometimes prove ineffective.

Population increases are not just in Texas; they have expanded in many states and now more than 36 states have established swine populations. States vary in removal practices but the end game is the same. Feral swine populations must be managed for the sake of wildlife, the environment and general economic development. A stable feral swine population can continue to exist if proper estimates and harvesting numbers are established. State residents are encouraged to seek out their individual state’s management policies and assist accordingly.

Pictures courtesy of: Mississippi State University

Twice a week, SCI Foundation informs readers about conservation initiatives happening worldwide and updates them on SCI Foundation’s news, projects and events. Tuesdays are dedicated to an Issue of the Week and Thursday’s Weekly Updates will provide an inside look into research and our other science-based conservation efforts. Follow us on Facebook and Twitter for more SCI Foundation news. 

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