The pot-bellied pig is a breed of domesticated pig originating in Vietnam with fourteen sub-species. Considerably smaller than standard American or European farm pigs, most adult pot-bellied pigs are about the size of a medium- or large-breed dog, though their bodies are denser at a weight of 60 to 300 lb (27 to 136 kg). Pot-bellied pigs can be easily discerned from other pig breeds by their size, upright ears and straight tail. The photos on this page show two larger pigs that are not in proper weight. Pigs with fat rolls over their eyes or a belly that touches the ground are easy visual indicators that the pig is overweight. Although they have a pot belly and a swayed back, it is not indicative of weight. Pigs in proper weight still have the sway and belly, but the hip bones can easily be felt with minimal pressure and the eyes (whole socket) should be easily visible.Because pot-bellied pigs are in the same species as ordinary farmyard pigs and wild boars, they are capable of interbreeding. The Swedish Agriculture Ministry has been assisting Vietnam with their pork production by introducing large breeds of pigs into Vietnam since the mid 1980s. Today, the Vietnamese and Swedish governments have realized that the indigenous Vietnamese Pig sub-species exist only in mountainous Vietnam and Thailand. The Vietnamese government has begun to subsidize local farmers that continue to raise the indigenous pot-bellied pigs because they realize they are not as prolific or large as other breeds.Pigs are extremely smart animals and having one as a house pet requires some preparation. Pig proofing the house as one would for a toddler is a must. They will learn how to open the refrigerator, they will pull books from the bookshelf, and any food at pig level is fair game. Due to their rooting behaviour during their young and adolescent years, books, newspapers and loose materials will often find their way in front of the pigs' nose to create a bedding area.Un-neutered male pigs, called boars, neutered males are "barrows" and female pigs, called "gilts" (young unbred females) or sows, become fertile at a young age, long before they are completely physically mature. Pot-bellied pigs are considered fully grown by six years of age, when their growth plates in their spine finally close.These small pigs are frequently kept as exotic pets in the United States and other Western nations. They are intelligent and easy to train to perform tricks for a food reward. Many pig owners walk their pets on leashes using a harness. Pigs can use a large modified litter box or modified mortar box just like a cat with no formal training, but if one has a yard, they are more easily trained to going outside than most dogs.There also exists the Göttinger 'mini' pig and the Resident of Munich miniature pig that are bred in medical labs, but are also frequently used as pets in Germany. The New Zealand Kunekune pigs are significantly larger than the Vietnamese Pot-bellied Pigs, but smaller than commercial pigs. Kune-Kunes are reasonably popular in the UK and were brought there in the early 1990s.George Clooney was famously known to have owned a pot-bellied pig named Max, although Max died in December 2006. See alsoList of pigs