One of the main reasons why the team selected the parakeets for the study was the fact that these birds almost never engaged in group yawning, so they were deemed reliable test subjects. During the tests, they were subjected to three temperatures – one that increased constantly, one that was high, to begin with, and one for control.

Examinations proved that the brain sought to cool itself by triggering the yawning reflex when the outside temperature was lower than that inside the body. “For instance, yawning should not occur when ambient temperatures exceed body temperature, as taking a deep inhalation of warm air would be counterproductive,” Gallup adds. “In addition, yawning when it is extremely cold may be maladaptive, as this may send unusually cold air to the brain, which may produce a thermal shock.”