Inner ear structure and electrophysiological audiograms of the subterranean mole rat, Spalax ehrenbergi.

Subterranean mole rats of the Spalax ehrenbergi superspecies in Israel have a distinctly developed vocal repertoire, presumably compensating together with olfaction for their complete blindness, thus providing an efficient communication system underground. Here we describe the unique organization of the cochlea of Spalax among mammals. The cochlea is subdivided into different subsystems where in the apical subsystem the fluid space and the organ of Corti differ remarkably from that in the basal subsystem, a feature as yet unknown in other mammals. The audiograms based on cochlear microphonics and on evoked potential recordings from the midbrain and brainstem, reveal a hearing range from 0.1 kHz-10 kHz with a best sensitivity between 0.5 and 1 kHz.