A sow is a female pig that has given birth. Hundreds of different breeds of pigs exist, all sharing similar birthing habits, despite their difference in size and color. Gestation for sows is a shade under 4 months, and, if allowed, they will prepare a nest before giving birth.
History
All domestic pigs come from Eurasian wild boars, but if one explores the family tree a little deeper, one discovers the genus Entelodont, or Terminator Pig, a very distant relative of modern wild boars and definitely not a candidate for farm life. Although pigs are considered omnivores, they aren’t really hunters; however, Entelodonts were vicious hunters. They grew to the size of cows, terrorizing North America around 30 million years ago. Eventually, they gave way to even larger pig-like creatures such as Daeodon, a beast the size of a bison whose jaws and teeth inspire fear even when viewing the fossils 20 million years later.