Pigs: Suidae

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PIGS: Suidae

FOREST HOG (Hylochoerus meinertzhageni): SPECIES ACCOUNTS
BABIRUSA (Babyroussa babyrussa): SPECIES ACCOUNTS
EURASIAN WILD PIG (Sus scrofa): SPECIES ACCOUNTS

PHYSICAL CHARACTERISTICS

Pigs are medium-sized mammals whose thick bodies weigh anywhere from 77 to 770 pounds (35 to 350 kilograms). Some domesticated, tamed, breeds weigh up to 990 pounds (450 kilograms). Pigs measure 34 to 83 inches (86 to 211 centimeters) in length and stand 21 to 43 inches (53 to 109 centimeters) high. The exception is the pygmy hog, which is the smallest species and never grows longer than 28 inches (71 centimeters).

The neck is short and the head is long and pointed. The snout is able to move separately from the head. The eyes are small, the ears are long, and each foot has four toes. The two middle toes are flattened and have hooves. The upper canines, cone-shaped teeth on each side of the front of the mouth, are big and curve upward, protruding from the mouth. Skin color varies, depending on the species, from brown to near black. Some species have manes or tufts of hair. Others have warts on the face.

GEOGRAPHIC RANGE

Pigs live on every continent except Antarctica. They also occupy a number of oceanic islands. They are not indigenous (in-DIJ-un-us), native, to all ranges, but have been introduced by humans.

HABITAT

Pigs live in altitudes of up to 13,000 feet (4,000 meters) and choose their habitats depending upon the availability of food, weather conditions, and the predator, animals that hunt pigs for food, population. African pigs occupy small territories or home ranges while other pigs tend to roam in search of better feeding grounds. Regardless of species, pigs build nests out of vegetation for protection from weather as well as for resting. Warthogs do not build their own nests but use those belonging to aardvarks. Home ranges must have sources of shade as well as water and mud holes. These three characteristics are important because some pigs do not have sweat glands to cool their bodies.

DIET

Wild pigs are omnivorous, eating meat and plants, feeding on leaves, grasses, seeds, fruits, eggs, young trees, carrion, or dead animals, invertebrates, or animals without backbones, and small vertebrates, animals with backbones. They also enjoy mineral licks where they ingest nutrient-rich soil or water.

BEHAVIOR AND REPRODUCTION

The basic group is the mother-offspring pair, and group sizes vary from one to fifteen pigs. Females live alone or in a group with other females, and offspring remain with their birth group up to two years. Female offspring sometimes remain with the group permanently, but males always leave. With the exception of the African species, males and females interact only during breeding season. African males live with the group year-round and help raise the young. Male warthogs breed, leave, and then return to help care for the offspring.

Pigs vocalize when they are alarmed or in pain as well as when they are comfortable or breeding. Displays are used to ward off intruders or rivals, but if that fails, pigs will fight using tusks. Cannibalism and infanticide, killing of young, have been observed in some species, and wild piglets have been known to be playful and social.

Wild pigs are active at night. Warthogs are active during daylight hours.

Male pigs breed with several females each season, but warthogs have been known to choose one mate for life. Courtship behavior includes chasing and calling. Pregnancy lasts 100 to 175 days, and during this time the female will build a nest from vegetation. Females give birth to one to twelve piglets in this secluded spot. The litters of domesticated pigs increase in number with age and may reach eighteen piglets. Piglets nurse, drink their mother's milk, up to twenty times each day. Some piglets are taken off mother's milk as early as five weeks, while others wait until thirty-two weeks of age. Sexual maturity of young is reached at eight months in some species, and at two to five years in others.

Primary predators of wild pigs are bobcats, coyotes, and black bears.

PIGS AND PEOPLE

Wild pigs and humans do not get along well. Wild pigs seriously damage crops by eating them or digging them up by the roots. Humans hunt pigs for their meat and they provide natives in Asia and parts of Africa with income through commercial hunting. Some wild pigs carry disease that threatens domestic livestock. In some cultures, pigs are used in place of money. Domestic pigs are used in scientific and medical research, and their organs have been used as replacements for human organs. Humans have been the recipients of pig hearts, kidneys, livers, lungs, and pancreas (PAN-kree-us) tissue.

CONSERVATION STATUS

The babirusa and the Philippine warty hog are Vulnerable, facing a high risk of extinction in the wild. The Javan pig is Endangered, facing a very high risk of extinction in the wild. The pygmy hog and the Visayan warty pig are Critically Endangered, facing an extremely high risk of extinction in the wild. There is no enough data about the Vietnam warty pig, but it may be extinct, died out.

GOOD NEWS FOR THE BABIRUSA

In February 2004, the Paguyaman Forest increased in size from 120 square miles (311 square kilometers) to 200 square miles (518 square kilometers). This forest is on Sulawesi, the island home to most of the remaining babirusa population.

In addition, a poacher, illegal hunter, was prosecuted in 2002 for participating in illegal trade. Such prosecution had never taken place before that, and it has served to discourage other would-be poachers. As a result, the number of babirusas sold weekly in the local markets fell from fifteen in 1991 to two in 2004.

The main threats to these wild pigs are hunting and loss of habitat. Although some pigs are protected by law from hunting, those laws are not well enforced.

FOREST HOG (Hylochoerus meinertzhageni): SPECIES ACCOUNTS

Physical characteristics: Forest hogs measure 51 to 83 inches (130 to 210 centimeters) in length and stand anywhere from 30 to 43 inches (76 to 110 centimeters) high. Males weigh from 319 to 606 pounds (145 to 275 kilograms) while females weigh 286 to 449 pounds (130 to 204 kilograms). Their skin is gray to blackish gray and is sparsely covered with long, coarse hairs. Tusks are around 12 inches (30 centimeters) or shorter.

Geographic range: Western, central, and eastern tropical Africa.

Habitat: Forest hogs live in forests of all kinds up to altitudes of 12,500 feet (3,800 meters). They require a permanent water source and prefer thick vegetation that does not grow too high to easily reach.

Diet: Forest hogs eat mainly grass. They will eat carrion and eggs occasionally. This species also eats dung, feces.

Behavior and reproduction: Forest hogs are active mostly at night, though they will come out during daylight if humans are not around. The social group is made up of one male, several adult females, and offspring. Home ranges overlap, and each has a number of paths leading to feeding sites, mineral licks, and water holes. Hyenas are the primary predators.

Mating occurs most often towards the end of a rainy season, and pairs do not bond. After 151 days of pregnancy, sows give birth to a litter of two to four piglets, but sometimes as many as eleven. Piglets remain in thick cover for one week and then stay with the sow. Young are weaned, no longer drink mother's milk, at nine weeks.

Forest hogs and people: Forest hogs are hunted for their meat. Some tribes use the hides for war shields. Others believe that killing the forest hog brings bad luck.

Conservation status: Forest hogs are not threatened. ∎

BABIRUSA (Babyroussa babyrussa): SPECIES ACCOUNTS

Physical characteristics: Babirusas weigh 132 to 220 pounds (60 to 100 kilograms) and measure 34 to 39 inches (87 to 100 centimeters) in length. They stand 25 to 32 inches (65 to 80 centimeters) tall. Depending on location, some babirusas look naked while others have long, stiff coats. Skin is brownish gray, and the tusks come out the snout and curve back towards the head.

Geographic range: Babirusas are found on the island of Sulawesi, the Togian islands, the Sulu islands, and the island of Buru.

Habitat: Babirusas are found primarily in tropical rainforests and along the banks of rivers and lakes where water vegetation is plentiful.

Diet: Babirusas feed on fruit, nuts, leaves, roots, and some animal material. They also eat soil and rock at the mineral licks. Both sexes have been known to eat their young.

Behavior and reproduction: Babirusas are most active in the morning. Males live alone, but females form groups with one to five other adult females and their young. Tusks are used for attack as well as defense, but aggressive behavior is also met with body pushing, rubbing, and boxing. Pythons are the babirusa's main predator.

Though they give birth year-round in captivity, they may do so less frequently in the wild. Pregnancy lasts 155 to 175 days and result in a litter of one to two piglets. These small litters make for a slow-growing population. Offspring are weaned between twenty-six and thirty-two weeks, though they begin to eat solid foods at one week. Sexual maturity is reached at five to ten months of age.

Babirusa and people: Babirusas are hunted both commercially and for its meat. Babirusa skulls are sold in local markets to tourists and in department stores in Jakarta, Indonesia.

Conservation status: Babirusas are considered Vulnerable. The main threats to this species include hunting and loss of habitat. ∎

EURASIAN WILD PIG (Sus scrofa): SPECIES ACCOUNTS

Physical characteristics: Eurasian wild pigs weigh from 77 to 770 pounds (35 to 350 kilograms), though domestic species can reach 990 pounds (450 kilograms). They stand anywhere from 22 to 43 inches (55 to 110 centimeters) tall. Their skin is covered with short bristles of varying color. Males have larger tusks than females.

Geographic range: Eurasian wild pigs are found on all continents except Antarctica. They also live on islands.

Habitat: Eurasian wild pigs live in a variety of habitats, including tropical rainforests, woodlands, grassland, and agricultural lands.

Diet: About 90 percent of the Eurasian wild pig's diet is vegetation. They feed on roots, grasses, fruits, seeds, nuts, agricultural crops, carrion, invertebrates and vertebrates. Eurasian wild pigs have been known to migrate, travel to another region, when food is scarce.

Behavior and reproduction: Eurasian wild pigs are mostly active in the morning and afternoon. The basic social unit is a small group of

females and their young. Adult males are solitary, lone. These pigs are active 40 to 65 percent of the time.

Eurasian wild pigs and people: Eurasian wild pigs are eaten by humans more than any other species of pig. Because they do major damage to crops, they are considered a pest by many locals. Eurasian wild pigs are hunted commercially and for food. Their skulls are displayed as protection from evil spirits. Domesticated pigs are used as money for the payment of fines or fees for brides in some cultures.

Conservation status: Eurasian wild pigs are not threatened. ∎

FOR MORE INFORMATION

Books:

Prothero, Donald R., and Robert M. Schoch. Horns, Tusks, and Flippers: The Evolution of Hoofed Mammals. Baltimore: Johns Hopkins University Press, 2003.

Sonder, Ben. Pigs & Wild Boars: A Portrait of the Animal World. New York: Todtri Productions, 1998.

Young, Allen M. Tropical Rainforests: A Golden Guide from St. Martin's Press. New York: St. Martin's Press, 2001.

Periodicals:

Bagla, Pallava. "World's Tiniest Wild Pig Subject of Big Rescue." National Geographic News (January 28, 2003). Online at http://news.nationalgeographic.com/news/2003/01/0128_030128_pygmyhogs.html (accessed on July 7, 2004).