There is evidence that the vestibular system of mammals has retained some of its ancestral acoustic sensitivity and that this sensitivity is mediated by the otolithic organs (most likely the sacculus, due to its anatomical location). In mice lacking the otoconia of the utricle and saccule, this retained acoustic sensitivity is lost. In humans vestibular evoked myogenic potentials occur in response to loud, low-frequency acoustic stimulation in patients with the sensorineural hearing loss. Vestibular sensitivity to ultrasonic sounds has also been hypothesized to be involved in the perception of speech presented at artificially high frequencies, above the range of the human cochlea (~18 kHz). In mice, sensation of acoustic information via the vestibular system has been demonstrated to have a behaviourally relevant effect; response to an elicited acoustic startle reflex is larger in the presence of loud, low frequency sounds that are below the threshold for the mouse cochlea (~4 Hz), raising the possibility that the acoustic sensitivity of the vestibular system may extend the hearing range of small mammals.