We studied the inner ear of Ctenomys talarum, a small solitary subterranean rodent distributed in the southern region of Buenos Aires Province (Argentina) using standard staining techniques. The inner ear of this subterranean rodent is characterized by a long basilar membrane, a higher density of cochlear receptors in the apical region of the basilar membrane and a gradual increment of the width of the triad of outer hair cells from the base towards the apex. These anatomical features of the cochlea of C. talarum can be interpreted as biomechanical specializations to enhance low-frequency sound reception.