There is scientific evidence supporting the claim that non-human animals can feel emotions and that human emotions evolved from the same mechanisms.
A distinction is sometimes made between “basic” emotions such as fear and anger, and “complex” human emotions such as jealousy and sympathy. However, this distinction is difficult to maintain, and animals are often said to express even the complex emotions.
In recent years, the scientific community has become increasingly supportive of the idea of emotions in animals. Prior to scientific support, evidence for animal emotion was based on anecdotal evidence provided from individuals who had frequent contact with animals. Recent scientific research has provided insight into similarities of physiological changes between human and non-human animals when experiencing emotion.