monkey finds old friend and brings good food

Emotions in animals are subjective feelings and emotions experienced by non-human vertebrates and, more controversially, other members of the animal kingdom. Emotions can be described as subjective conscious experiences that are primarily characterized by psychophysiological expressions , biological responses , and mental states .

Charles Darwin was one of the first scientists to write about the existence and nature of emotions in non-human animals. His observational, sometimes anecdotal approach has evolved into a more robust hypothesis-driven science approach. A general hypothesis related to the relationship between humans and non-human animals also supports the claim that non-human animals can feel emotions and that human emotions are mediated by similar mechanisms.