Pigs are complex and intelligent animals that exhibit a rich array of social behaviors. They live in groups, interact with others of their species, and form relationships, fitting the description of highly social creatures. This social nature shapes many aspects of their lives, from foraging to raising their young.
Life in a Group: Pig Communities
Pigs naturally live in structured social groups. Wild pigs, known as wild boars (Sus scrofa), typically form family groups called sounders. These sounders usually consist of four to six related sows and their offspring from the past one to two years. Young males often leave the sounder upon reaching sexual maturity, sometimes forming small bachelor groups or living solitary lives. Young females, however, tend to remain with their birth group or establish new sounders nearby.
Group living influences their daily routines and survival strategies. Within a sounder, pigs commonly engage in communal resting, returning to a shared location at night, often in areas with dense cover. This helps maintain social bonds and provides security. Domestic pigs, descendants of the wild boar, retain these social patterns. They thrive in stable groups, preferring to live with familiar individuals rather than mixing with new ones.
The size and composition of pig groups vary based on resource availability and environment. Wild sounders maintain territories from 100 to 2,500 hectares, minimizing encounters with unfamiliar pigs. In agricultural settings, pigs are housed in groups, forming hierarchies and seeking social contact despite differing environments. Living in stable social units contributes to their overall well-being.
How Pigs Interact
Pigs utilize diverse communication methods, including vocalizations, body language, and scent marking. They have over 20 distinct vocalizations, such as grunts, squeals, barks, and screams. Low-pitched grunts signal contentment or are used as contact calls, while short, repetitive grunts indicate excitement. High-pitched squeals and screams are associated with distress or fear.
Pigs communicate through body language. Tail position conveys emotion: a curled or wagging tail indicates arousal or excitement, while a drooping tail signals fear. Ear movements also communicate, with ears directed forward implying a positive or neutral state, or signaling heightened vigilance.
Social order within a pig group is established through a linear hierarchy, where older and larger sows dominate younger or smaller individuals. This hierarchy is stable over time, leading to infrequent overt aggressive behaviors within established groups. However, when unfamiliar pigs are introduced, aggression, including rooting, pushing, and biting, occurs as they work to re-establish a new social structure. This process of hierarchy formation stabilizes within 24 to 48 hours.
Pigs display cooperative behaviors. They huddle for warmth, using collective body heat for insulation. Pigs engage in communal nesting and shared maternal care, where one sow might remain with piglets while others forage. Piglets coordinate their nursing efforts, and some groups engage in communal rearing of young. These cooperative actions highlight their ability to work together.
Play is important for pig social interaction, particularly among younger pigs. Play, such as “rough-and-tumble” or locomotor play, involves chasing, shoving, and mock biting of shoulders and ears. This play helps in social bonding and development, and its presence indicates good welfare, occurring when primary needs are met. Maternal care also reinforces social development, with sows building elaborate nests before farrowing and calling their piglets to nurse. The strong bond between a sow and her piglets contributes to the piglets’ early social learning and survival.
Why Understanding Pig Social Behavior Matters
Recognizing the social nature of pigs has implications for their welfare and management in human-animal interactions. Pigs have complex social needs that, when met, contribute to their physical and mental health. Providing opportunities for social interaction and natural behaviors can reduce stress and improve their overall quality of life. For instance, pigs in enriched environments exhibit reduced levels of harmful social behaviors like tail biting.
Understanding pig social dynamics is important in managing group housing systems. Aggression can increase when unfamiliar pigs are mixed, highlighting the need for stable social groups. Management practices that facilitate communication and hierarchy establishment among pigs mitigate these aggressive encounters. Providing appropriate social enrichment, including interactions with other pigs and humans, supports their well-being.
The ability of pigs to express their social behaviors is relevant to their welfare, especially in farmed environments. When pigs are unable to perform natural social behaviors, they can experience frustration, which may lead to undesirable behaviors. Therefore, designing environments that accommodate their social structures, communication needs, and behavioral patterns is practical for those interacting with pigs, from agricultural settings to pet ownership. This awareness supports practices that promote a more positive and enriching existence for these animals.