Why do captive pigs exhibit foraging-like behaviors?
Captive domesticated pigs are provided with food and thus do not need to forage. However, they still spend large amounts of their time exhibiting foraging-related behaviors such as rooting, sniffing, biting, and chewing on edible and inedible materials. Often, they are provided with hay so they may carry out these behaviors (Studnitz et al., 2007). When deprived of material suitable for these behaviors, pigs perform stereotypies, which are fixed repetitive actions indicative of boredom or frustration (Grandin, 2009). In pigs, stereotypies may include chewing metal bars on their crates, pacing, and chewing with nothing in their mouths. The importance of foraging behaviors and the relationship between pig stereotypies and inability to forage are well established. When pigs kept on concrete floors were allowed access to soil outdoors, they immediately began to root (Day et al., 1995). Pigs with nose rings do not root, presumably because the pressure of the ring causes pain when rooting (B
