The terms pig, hog, boar, and swine are often used interchangeably, leading to confusion. In biology and agriculture, however, each word carries a specific, defined meaning related to the animal’s classification, size, sex, or environment. Understanding these definitions—which depend on the scientific family name, weight, reproductive status, and whether the animal is domestic or wild—is key to clarifying the terminology.
Swine: The Biological Classification
The umbrella term that encompasses all pigs, hogs, and boars is swine, which refers to any member of the biological family Suidae. The domestic pig is classified under the genus Sus and is formally known as Sus scrofa domesticus.
It shares its species name, Sus scrofa, with the Eurasian wild boar, its direct ancestor. This connection shows that differences are variations based on domestication, breeding, and environment, not species-level distinctions. The family Suidae also includes other related, non-domesticated animals like warthogs and babirusas, which are native to the Old World.
Hog and Pig: Common Terms of Size and Use
The terms “pig” and “hog” are used in agriculture to differentiate the animal based on size. A pig generally refers to a young animal that has not yet reached maturity or market weight. For example, a suckling pig is a very young animal, butchered before it is weaned.
A hog, by contrast, is a large domestic swine that is typically ready for market and intended for slaughter. While the exact weight varies, an animal is often considered a hog when it weighs more than 120 pounds, with market-ready weights usually between 200 and 285 pounds.
Boar, Sow, and Barrow: The Role of Sex and Status
The distinction between a boar and a pig or hog is based purely on the animal’s sex and reproductive status. A boar is defined as any male pig that has its testicles intact and is typically used for breeding. Therefore, a boar is a type of male pig or hog, identified by its ability to reproduce.
A sow is an adult female pig that has already given birth to at least one litter of piglets. Prior to giving birth, an intact female is referred to as a gilt, making the sow status contingent on reproductive history.
A barrow refers to a male pig that was castrated before reaching sexual maturity. Castration is performed on males not intended for breeding to improve meat quality and eliminate the risk of “boar taint,” an off-flavor associated with intact adult males.
Wild Boars Versus Feral Hogs
The use of the word “boar” in the wild context adds complexity, particularly in North America. The term wild boar properly refers to the true, non-domesticated species, Sus scrofa, which is native to Europe and Asia. These animals were introduced to the United States primarily for hunting.
Feral hogs, often called wild pigs or razorbacks, are descendants of domestic pigs (Sus scrofa domesticus) that escaped human control and established wild populations. These animals have adapted to the wild, often regaining ancestral physical traits like longer snouts and thicker hair. In many regions, the wild boar and feral hog populations have interbred, resulting in hybrid animals that share genetics from both the true wild ancestor and the escaped domestic stock.