servile adjective. âº âeager to âserve and âplease someone âelse in a way that âshows a âlack of ârespect for yourself: As a âwaiter, you âwant to be âpleasant to âpeople without âappearing servile. (Definition of servile from the Cambridge Academic Content Dictionary Â© Cambridge University Press).
That is a good question. In fact, it is not really known why horse yawn. Some suggestions for this behavior are the following: 1  Change of sleeping, napping and waking state. 2  Physical fatigue. 3  Mental stress.  Release of mental or physical stress. Horses will often yawn after a chiropractor session or massage session.
Causes of yawning a lot. The central cause of excessive yawning or yawning a lot is low CO2 (carbon dioxide) and oxygen levels in brain cells. Most modern people constantly have low brain and body oxygenation. Let us consider why. The physiological norm for breathing at rest (for adults) is only 6 L/min.