In stumptail monkeys from birth to adulthood, and in very young human infants, the epiglottis serves to guide the larynx upwardly behind the soft palate so it can lock into the nasopharynx and remain there during respiration. After early infancy in man the attainment of a larynx-nasopharynx connection is uniquely lost, causing the epiglottis to have no essential function.