The coat coloration patterns observed among populations of feral hogs (also called wild hogs; Sus scrofa) are extremely diverse (Fig. 1). Much of this variation stems from the varied ancestral origins of these populations (History of Feral Hogs in the United States). In general, feral hog coat coloration varies from solid to mixed patterns.
The simplest of these is the solid coloration. This can be expressed as any of the basic colors (that is, black, red-brown, or white), and is observed in feral hogs and hybrids.
The next pattern is spotted or mottled. This is a mixed pattern of two or more of the basic colors and is highly variable. Again, this pattern is observed only in feral hogs and hybrids. The most unique or unusual is the belted or shoulder band pattern. This is often referred to as a Hampshire band after the domestic breed most recognized for this specific coloration pattern. The belted pattern has a base coloration of either black or some shade of red-brown, with a white band completely around the shoulder region and on the front legs. The black base is much more common. In spite of being genetically dominant, shoulder bands are not common among feral hogs. It has been observed in both feral hogs and hybrids. Uncommon in occurrence, a form of counter shading can also be seen in feral hogs. This consists of a darker upper color with a lighter color toward and on the underside. This is typically seen with either black or red-brown as the upper color and white as the underside counter-shading. This can also been observed in combination with spotting. The presence of light points can be observed with any of the aforementioned patterns. Light points consist of white coloration on the ends of the snout, ears, legs, and tail. The coverage of this pattern can be extensive or just a small amount.
Figure 1. Diverse coat color variation as exhibited in one sounder of feral hogs.
The most complex pattern observed in wild hogs is the adult wild/grizzled pattern exhibited by Eurasian wild boar and some hybrids with feral hogs (Fig. 2). Contrary to earlier anecdotal descriptions, pure wild boar are not solid black. The wild/grizzled pattern includes a coat of light brown to black with white or tan ends on the bristles, especially over the sides of the head and end of the snout. The face, cheeks, and throat are grizzled in appearance with white-tipped bristles. The undersides are lighter, and the points (similar to the light points defined above) are dark brown to black. A distinct dark stripe can also be evident in the chest region or the mid-back of the adult coloration pattern.
Figure 2. Wild/grizzled coat coloration pattern exhibited in Eurasian wild boar.
Some wild hogs exhibit a striped juvenile pattern (Fig. 3). This coloration has been described as a “chipmunk-like” or “watermelon-striped” pattern. It consists of a light grayish-tan to brown base coat, with a dark brown to black spinal stripe and three to four brown irregular longitudinal stripes with dark margins along the length of the body. This is found in all of the subspecies of Eurasian wild boar, wild boar/feral hog hybrid populations, and in some feral hog populations. This coloration pattern, assumed to function as camouflage for the young piglets, changes to the adult pattern at between four to six months of age. After losing the striped juvenile pattern, wild boar or some hybrids enter a reddish phase of the adult coat coloration pattern. This will usually persist until these animals are about a year old.
Figure 3. Striped juvenile coat coloration pattern exhibited in Eurasian wild boar and some wild boar x feral hog hybrids.
The frequency of coat coloration patterns varies among feral hog populations. Solid black is often cited as the most common pattern but spotted coloration is the most common pattern observed. The only uniform coat coloration patterns are seen within pure Eurasian wild boar populations; however, even those populations show the age-related variation exhibited by these animals (that is, striped juveniles, immature reddish phase, and grizzled/wild adult pattern). In addition, spotting patterns have even been reported in pure wild boar populations. Based on a sample of 4,014 wild hogs from 13 populations in the United States, the coat coloration percent breakdown was as follows: all black 32.0%; all white 6.1%; all red/brown 4.7%; spotted 50.6%; belted 2.8%; wild/grizzled 3.5%; and miscellaneous 0.3%. “Miscellaneous” includes infrequent or rare coloration patterns such as blue or gray roans.