Rôle fonctionnel des bulles tympaniques géantes de certains rongeurs (Meriones)

Some mammalian species, particularly rodents from desert regions, present hypertrophied bullae. This feature may be related to their acoustical properties. The amplitude of the microphonic potential is much larger for frequencies around the resonance of the middle ear even for high intensities. The response curve has the shape of a resonance curve. This suggests a low damping of the oscillatory system constituted by the middle ear structures. The anatomical study seems to agree with a damping by reactance. The organ of Corti possesses supporting cells of large size which probably bear some relation to large displacements.