The guinea pig is a gentle, highly social rodent, that commonly serves as a companion animal and an experimental model in North America and Europe. Food preferences are established early in life, and a guinea pig can refuse to eat if their food type or presentation is changed. For this reason, small mammal veterinarians recommend exposing juvenile guinea pigs to a variety of chows and vegetables. Guinea pigs also do not tolerate environmental changes well. When exposed to something perceived as dangerous, the response of the guinea pig is generally to freeze, or less commonly flight.