A<unk>  is a reflex consisting of the simultaneous inhalation of air and the stretching of the eardrums, followed by an exhalation of breath. Many animal species, including birds and fish, experience<unk> ing. The study of<unk> ing is called chasmology.<unk> ing (oscitation) most often occurs in adults immediately before and after sleep, during tedious activities and as a result of its contagious quality. It is commonly associated with tiredness, stress, sleepiness, boredom, or even hunger. In humans,<unk> ing is often triggered by the perception that others are<unk> ing (for example, seeing a person<unk> ing, or talking to someone on the phone who is<unk> ing). This is a typical example of positive feedback. This "contagious"<unk> ing has also been observed in chimpanzees, dogs, cats, birds, and reptiles and can occur between members of different species. Approximately twenty psychological reasons for<unk> ing have been proposed by scholars but there is little agreement on the primacy of any one. During a<unk> , the tensor tympani muscle in the middle ear contracts. This creates a rumbling noise perceived as coming from within the head; however, the noise is due to mechanical disturbance of the hearing apparatus and is not generated by the motion of air.<unk> ing is sometimes accompanied, in humans and other animals, by an instinctive act of stretching several parts of the body including the arms, neck, shoulders and back.
Yawn
Nightmare
Bedpan
Nightscout
Hwabyeong
Hangnail
Uinyeo
Sleep sex