Wild Boar

The wild boar is a wild pig, the species Sus scrofa, and the ancestor of every domestic pig on farms today. Scrofa is Latin for sow. Wild boars and domestic pigs are the same species, which is why they can breed together and why escaped farm pigs so easily turn wild. The word boar can mean the whole species or just an adult male. A female is called a sow, the young are piglets, and a family group is a sounder. In North America, people often say wild hog, wild pig or feral hog, and those names usually cover pure wild boars, feral domestic pigs and hybrids between the two, which can be hard to tell apart. So what is the difference between a boar and a hog? In everyday use, hog is a general word for a pig, especially a large one, while boar points to the wild animal or to a male. Pigs were first domesticated from wild boars more than 10,000 years ago in the Near East, in the upper Tigris basin, and separately in China about 8,000 years ago. Thousands of years of breeding made farm pigs rounder, paler and calmer. Wild boars kept their long legs, bristly coat, tusks and sharp senses, the tools they need to survive in the wild.

Wild boars vary in size more than almost any other large mammal, and the farther east you go, the bigger they get. In most of Europe, males average 75 to 100 kilograms (165 to 220 pounds), stand 75 to 80 centimeters (30 to 31 inches) at the shoulder and measure about 150 centimeters (5 feet) long. Females average 60 to 80 kilograms. Around the Mediterranean they are smaller, and some males there average only 50 kilograms. In the richest parts of Eastern Europe, males average 110 to 130 kilograms, and the largest males in Western and Central Europe reach about 200 kilograms (440 pounds). The true giants live in northeastern Asia. The Ussuri boar of the Russian Far East and Manchuria is the largest subspecies, and some males there have been recorded at 300 to 350 kilograms (660 to 770 pounds) and 125 centimeters at the shoulder. Males are 20 to 30 percent heavier than females. The head can make up a third of the body length, and the body is narrow and deep, built for pushing through thick brush. The lower tusks show 10 to 12 centimeters (4 to 5 inches) and keep growing all through a male's life. The coat is made of coarse bristles over a soft winter underfur, and its color goes from gray and brown to black. Some boars near Lake Balkhash in Kazakhstan are very pale.

There is only one species of wild boar, but scientists recognize about 16 subspecies, grouped into four regional groups: Western, Indian, Eastern and Indonesian. The Western group includes the European or Eurasian wild boar, the form most people picture, and the small boars of the Mediterranean, such as those of Sardinia. The Eastern group includes the huge Ussuri boar of the Russian Far East and the boars of Japan, where the Honshu boar covers most of the country and the small Ryukyu boar lives on the southern islands. The Indian group includes the crested, long legged boars of India and Sri Lanka, and the Indonesian group is a single subspecies, Sus scrofa vittatus, which lives on islands such as Sumatra, Java and Bali and eats mainly fruit. In the United States, hunters talk about Russian boars. These are European wild boars that were brought over for hunting, starting with releases such as the one at Hooper Bald, North Carolina, in 1912, and later Russian boar imports from the 1990s. Most wild pigs in the Americas and Australia today are not pure wild boars at all but feral domestic pigs, called razorbacks in some places, or hybrids between the two. Wild boars should not be confused with other wild pig species, such as the warthog and bushpig of Africa or the bearded pig of Borneo.

The wild boar has one of the largest ranges of any land mammal. Its native range runs from Portugal and Morocco across Europe, the Middle East and Central Asia to Siberia, Japan, India, Sri Lanka and the islands of Indonesia. The IUCN lists it as native in more than 80 countries. It has disappeared from Egypt, Libya and Ireland. In Britain it was wiped out around the thirteenth century, and in Sweden it vanished long ago too, but in both countries it came back from farm escapes from the 1970s onward, and the IUCN now counts them as reintroduced. Outside its native range, the IUCN lists introduced populations in Argentina, Brazil, Cuba, the Dominican Republic, Haiti, Jamaica, the Galápagos Islands of Ecuador, the United States, Australia, New Zealand, Papua New Guinea, Fiji and South Africa, among others. In the United States, the IUCN names states such as Texas, Florida and Hawaii, and feral pigs are also widespread in California. Wild boars can live almost anywhere that offers food, water and cover: broadleaf and mixed forests, Mediterranean scrub, reed beds and marshes, mangroves, river forests in deserts, grasslands, farmland and, more and more, the edges of cities. What they avoid are places with deep snow, which makes digging for food impossible, and very dry open country without shade or water.

Wild boars are true omnivores and will eat almost anything they can find, smell or dig up. Most of their food comes from plants: roots, tubers, bulbs and rhizomes they root out of the ground with their snouts, along with nuts, berries, seeds, leaves and bark. In the temperate forests of Europe and Asia, acorns and beechnuts are their most important food, and years with a big acorn crop lead to more piglets the following spring. On the island of Java, the local boars eat mainly fruit, especially figs. In warm months they add a lot of animal food: earthworms, insects and their larvae, snails, fish, frogs, lizards, snakes, mice and other rodents, bird eggs and chicks, and carrion. They will also eat garbage near towns. A boar of 50 kilograms needs around 4,000 to 4,500 calories a day, and finding that much food takes hours of foraging, mostly at dusk and through the night. This flexible diet is what makes wild boars so successful, and also what makes them a problem for people. They raid fields of corn, wheat, potatoes, rice and sugarcane, strip vineyards and plow up pastures, lawns, golf courses and gardens with their snouts. In places like Texas, Australia and Brazil, the damage costs farmers huge sums every year.

Wild boars live in family groups called sounders, led by an old female, the matriarch. A sounder is made up of related sows and their young of the last year or two. Young males leave the group at 8 to 15 months old, and adult males spend most of the year alone, joining the sows only in the breeding season. Wild boars are active at any time of day, but where people hunt them, they become mostly nocturnal, resting in thick cover by day and coming out at dusk. They love mud. Wallowing in mud cools them down in summer and helps get rid of parasites, and afterward they rub against trees, leaving marks at the height of their shoulders. Their sense of smell is excellent, good enough that police in Germany have trained boars to sniff out drugs. Their hearing is sharp, but their eyesight is weak: they see no colors and cannot recognize a person standing still 10 to 15 meters away. Despite their heavy build, wild boars can run at about 40 kilometers per hour (25 miles per hour) and jump over obstacles 140 to 150 centimeters high. They are also strong swimmers. In 2013, a wild boar swam 11 kilometers (7 miles) from the coast of France to the island of Alderney in the English Channel.

In Europe, the wild boar's breeding season, or rut, runs from November to January. Adult males join the sounders, fight rivals with their tusks and thick shoulder shields of skin and fat, and a single male may mate with five to ten sows. They eat so little during the rut that they can lose about a fifth of their weight. Pregnancy lasts from about 114 to 130 days in young sows and up to 140 days in older ones, so most piglets are born from March to May. Before giving birth, the sow leaves the sounder and builds a nest of grass, leaves and branches, sometimes with a roof. Litters usually have four to six piglets, and up to ten or twelve. Newborn piglets weigh 600 to 1,000 grams (1.3 to 2.2 pounds) and are dark brown with pale stripes running along the body, a camouflage pattern that hides them in the dappled light of the forest floor. The stripes fade after three to four months, and the young have the adult color by about eight months. Mothers are very protective, and a sow with piglets is the most likely wild boar to charge a person. Females can breed at one year old, and males at two, though most males do not win a chance to mate until they are four or five. Wild boars can live 10 to 14 years in the wild, but few live past four or five. In captivity they have reached 20.

Outside their native range, wild boars and feral pigs are among the most damaging invasive animals in the world. Christopher Columbus released pigs in the West Indies on his second voyage, and Hernando de Soto brought them to Florida in 1539. Over the centuries, escaped farm pigs and wild boars released for hunting spread across the Americas. In the United States, the feral swine population was estimated at around six million in 2013, and the Department of Agriculture puts the minimum cost of their damage at 3.4 billion dollars a year. Texas has the most, around 2.6 million. Since 2014, 12 states have managed to eliminate them. Feral pigs dig up crops and pastures, foul water, eat the eggs of ground nesting birds and sea turtles, compete with native animals and spread diseases such as brucellosis, which about 8 percent of US feral swine carry. In Australia, pigs brought by European settlers have spread across much of the continent and number in the millions. In Brazil, wild boars that crossed from Uruguay around 1989 mixed with domestic pigs to form the javaporco, and hunting them has been allowed in Rio Grande do Sul since 2005. In Argentina, Pedro Luro brought European boars to La Pampa around 1906, and they have since spread to many provinces. Because sows breed so fast, about two thirds of a feral pig population has to be removed every year just to keep numbers steady.

Across most of its native range, the main predator of the wild boar is the gray wolf. Wolves hunt boars all year, and a single wolf can kill around 50 to 80 boars a year, mostly piglets and young animals. In Asia, tigers depend heavily on wild boars. In the Sikhote Alin mountains of the Russian Far East, a single Amur tiger kills about 30 to 34 boars a year, and boars are also one of the most important prey of Bengal tigers in India, Nepal and Bangladesh. Until the late nineteenth century, tigers were the main predator of boars in the Caucasus, Kazakhstan and Central Asia too. Leopards and dholes also hunt them, and on the Indonesian islands of Komodo, Rinca and Flores, the main predator of wild boars is the Komodo dragon. Piglets face many more enemies, including lynx, brown bears, snow leopards, jungle cats, eagles and pythons, while saltwater crocodiles take adult pigs in places such as northern Australia and Southeast Asia. Outside their native range, wild boars often have few natural predators, which is one reason feral pig populations grow so quickly. Even so, cougars hunt them in the Americas and dingoes in Australia. A full grown male boar is a dangerous animal to tackle, and wolves and leopards usually avoid big males, going for sows, piglets and younger boars instead.

Wild boars usually avoid people and run away long before anyone sees them. Attacks are rare, but they do happen, mostly when a boar is wounded, cornered, surprised at close range or protecting piglets, or when boars have learned to expect food from people. A charging male can cause deep wounds to the legs with its tusks, and sows bite. If you meet a boar, stay calm, give it room to leave, keep dogs on a leash and never get between a sow and her young. In many cities, including Berlin, Barcelona, Rome, Haifa and the outskirts of Seoul, boars now come into streets and gardens to look for food, and feeding them is the main reason they lose their fear of people. Wild boars have been hunted for food for thousands of years, and in much of Europe the meat is a traditional autumn and winter dish. Can you eat wild boar? Yes, but the meat must be cooked thoroughly, because wild boars can carry trichinella worms, and hunters who handle carcasses in places like the United States can catch brucellosis. Today, one of the biggest worries about wild boars is African swine fever. This virus does not affect people, but it kills almost every pig it infects, wild or domestic. It has spread through wild boars in much of Europe and Asia since 2014, leading to large culls and fences along borders.

The IUCN lists the wild boar as Least Concern, in a global assessment carried out in May 2018 and published in 2019. Its population trend is listed as unknown, which mostly reflects how hard it is to count such a widespread animal, not a sign of decline. In fact, in much of Europe wild boar numbers have grown strongly over the last fifty years, helped by milder winters, more corn and other crops, more forest and fewer large predators. Hunting bags in many countries have risen year after year. The picture is not the same everywhere. In parts of Southeast Asia, heavy hunting for meat has made wild boars scarce in some forests, and the small boars of some islands have their own local problems. The IUCN lists livestock farming, hunting and trapping, and invasive species and diseases among the threats. The biggest current threat is African swine fever, which has killed large numbers of wild boars in Europe and Asia and led to mass culls in countries such as Estonia, Latvia, Lithuania, Poland and South Korea. Another problem is mixing with domestic pigs, which dilutes the genes of wild populations. In most places, though, the challenge with wild boars is not saving them but managing them, and in their introduced range the goal is often to remove them entirely.