Sense of smell Certainly the most celebrated anatomical feature of the pig is its snout, the disc-like movable tip of the muzzle that incorporates the central part of the upper lip. The snout is supported by the rostral bone - a structure unique to the pig (Dyce et al., 2010). Olfactory cells, present in the nasal epithelium, convert incoming odor molecules into electrical signals, which are then transmitted via the olfactory nerve to the brain. In addition, the vomeronasal organ, located in the upper air passages, contains receptors that have access to the central nervous system through the accessory olfactory bulb. The sense of smell develops early in pigs and is important to survival because piglets are very mobile at birth. They can and need to follow chemical cues learned earlier in life, e.g., the odor of their mother. Morrow-Tesch and McGlone (1990) demonstrated that piglets preferred sow fecal odors and did not prefer to be near novel odors (orange and banana odors). Campbell (1976) fed sows a flavored diet during lactation and fed piglets the same flavor diet at weaning. When given no alternative diet, weaned pigs from dams that had eaten the flavored diet ate more feed in the 2 weeks post weaning compared to those that had not been exposed to the flavor. Pigs have a highly sensitive sense of smell relative to other animals. Feral pigs use their sense of smell to find food, detect potential predators or prey, and mark territory. In one experiment, sows learned to distinguish between otherwise identical cards that they had previously touched or not touched. The odor they deposited in this way was still perceptible to them after several hours and even after the cards were washed (Signoret et al., 1975). Pigs