Humans are one of the species who laugh.
Laughter is a sense of feeling good, happy and joyful. It is a response to humour, comprising two parts, gestures and the production of sound. A hearty laugh triggers changes in the various parts of the body like arm, leg and trunk muscles. Fifteen facial muscles contract when we laugh. Laughing is a kind of facial exercise. In extreme laughter, tear ducts also get activated. It has been proven that laughter can help fight illness and improve health.
The lacrimal system is responsible for producing and secreting tears. It is situated near the eyeball. A person sheds three types of tears that are basal tears that keep the cornea nourished and lubricated; reflex tears, which help to wash out an irritant in the eyes from foreign particles like onions, and psychic or crying tears produced in response to any strong emotion caused by stress, pleasure, anger, sadness, and physical pain. These tears help us feel better after a good cry.