Pigs are relatively nearsighted and have poor three-dimensional vision. However, they do have a keen sense of hearing, and communicate in the group by means of a language consisting of grunting and squeaking noises. If one animal makes a warning sound, the entire group will be on alert. Pigs are frightened by sudden unfamiliar noises. Pigs move slower than humans and need time to get used to a new space .
Pigs possess a poor temperature regulation system.
They warm one another by forming piles . Due to breeding for high volumes of meat and quick growth, the pig s circulatory system has not sufficiently kept up. Animals with pneumonia and pericarditis who have gotten ill while being fattened are particularly sensitive. They suffer breathing difficulties and oxygen deficiencies even at relatively low stress levels, and usually die first. Pigs are omnivores with a one-chamber stomach.