Humans can mimic the behavior of others and produce the same emotional experiences, a phenomenon known as emotional contagion. Rodents (mainly rats and mice) are commonly used as experimental animals in medical research. These animals can also suffer from emotional contagion associated with negative emotions such as fear, anxiety, and depression. To further understand the process of the transmission of different emotions among animals, we review the definition and process of emotional contagion, as well as the influencing factors and the main types and their physiological mechanisms, to provide a reference for subsequent studies.