Why do feral hogs rub on trees?

Feral hogs will rub on trees, fence posts, utility poles, and other objects in an effort to control external parasites. These are called rubs and are not breeding or territory related.  Sometimes rubs are also used to simply scratch an itch.Feral hog rub on utility pole.

Physical Characteristics of Feral Hogs

Figure 1. Appearance of a typical adult male feral hog (i.e., a wild hog from a population that is solely of domestic ancestry).

The introduced feral hogs (also called wild hogs; Sus scrofa) in the United States exhibit a broad range of physical characteristics.  To a large part, this variability stems from the widely diversified ancestral origins of these animals. In general, both free-ranging domestic swine (i.e., feral hogs; Fig. 1) and introduced Eurasian swine bloodline comprised the initial …

Feral Hog Reproductive Biology

Feral hogs (also called wild hogs; Sus scrofa) are characterized by high reproductive potential, with a young age at puberty, large litters, and frequent breeding.  The recent expanding range of this non-native species provides evidence of its high reproductive capacity.  In general, the various aspects of the reproductive biology of feral hogs in the United States are intermediate between that of domestic swine and the Eurasian wild boar.  However, these various reproductive parameters can vary widely between populations of …

Quick Facts on Feral Hogs

Feral hog numbers are on the rise in the United States.  Likewise the problems they cause are also growing.  With attention on this invasive species, many myths are circulating about feral hog history, distribution, biology, and damage.  The following bullets will help get the facts straight.

History and Distribution

  • Swine were domesticated thousands of years ago from wild stock in Europe and Asia.
  • Swine were first introduced to North America by Spanish explorers. 
  • Confined and/or free-ranging domestic swine escaped from

Feral Hog Population Biology

The population biology of feral hogs (also called wild hogs; Sus scrofa) is unique among most large mammals, in that these animals have a high reproductive potential combined with a high mortality rate.  Populations of these animals have been reported to fluctuate in response to a combination of several factors (for example, density, food availability, severe weather conditions, disease outbreaks, and hunting).  Such external influences can result in high levels of mortality occurring within these populations.  However, because of …

Natural Predators of Feral Hogs

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 …

Food Habits of Feral Hogs

Feral hogs (also called wild hogs or wild pigs; Sus scrofa) are omnivorous and very opportunistic in their food habits.  Their feeding behavior is one of the main reasons why this species has been so successful in establishing new populations in areas previously without feral hogs.  The year-round diet of feral hogs is composed primarily of plants with smaller amounts of algae, fungi, animals, and other material (Fig. 1).  Their diet depends on food availability.  The types of food …

Why are feral hog populations expanding?

Feral hogs are expanding their range because of high reproductive output and wide variety of suitable habitats available to them.  Additionally, only a few predators are willing to take adult feral hogs.  Populations of feral hogs are showing up in new areas away from other feral hog populations.  This is likely due to escape from pens and from intentional, illegal releases of feral hogs.


Rooting Behavior of Feral Hogs

Figure 1.  This field was rooted up by feral hogs. Photo courtesy of Jack Mayer.

Characteristics of Rooting Behavior

One of the more destructive habits of feral hogs is their rooting behavior.  Feral hogs root to obtain foodRooting breaks up and loosens the surface and near-surface layers of the soil column.  Rooting behavior varies significantly between locations and habitats, depending on size and depth of area uprooted  (Fig. 1).  It can differ from shallow disturbance or …