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.
A long-standing hypothesis is that yawning is caused by an excess of carbon dioxide and lack of oxygen in the blood. The brain stem detects this and triggers the yawn reflex. The mouth stretches wide and the lungs inhale deeply, bringing oxygen into the lungs and hence to the bloodstream.s such, the stretching of jaw and face muscles seems to be necessary for a good yawn.The yawn reflex is often described as contagious: if one person yawns, this will cause another person to sympathetically yawn. The reasons for this are unclear; however, recent research suggests that yawning might be a herd instinct.