It's thought that shorter ear canals may have helped them better deal with stimuli caused by things like variations in pressure and the movements of their heads while swimming and diving, though there is still some debate about this.

人们认为， 较短的耳道可能有助于他们更好地应对由压力变化和游泳和潜水时头部运动等因素引起的刺激，尽管对此仍有一些争论。