Pigs (animals of the Genus Sus), of which there are nine extant species within the wider Family Suidae, are adaptable polytocous (giving birth to multiple offspring at one time) omnivores, that occupy a variety of ecological niches in temperate zones largely across Europe and Asian. Pigs have a long history of use by humans, culminating in the process of domestication, which resulted in the variety of breeds of domesticated pigs (Sus scrofa domesticus) existing currently. Today, pigs have economic, scientific, and cultural significance around the world. The domestic pig is farmed in large numbers, and increasingly, pigs are used as animal models in biomedical research because of their biological similarity to humans. Pigs are also kept as pets, and in some areas feral pig populations or wild boar are considered an invasive pest species. In a farming context, pigs may experience pain during necessary parts of the production cycle, e.g. parturition, through deliberate management interventions, e.g. castration, tail docking, teeth resection, or from various diseases or disorders that may occur at increased prevalence in intensive farming systems. In the research context, pigs may experience induced pain in studies where pain is an outcome measure or, more commonly, as the result of ineffective pain management after noxious scientific procedures. A variety of approaches have been used for pain assessment in the pig, and approaches to pain mitigation have been extensively researched to increase the ethical justification for using the species in research. Yet despite this work, pain remains a central welfare problem for large numbers of pigs across the world in both the farmed and research contexts.