Hearing
In mammals the cues for hearing are usually based on inter-aural intensity differences, which occur as a result of the diffraction of a progressive sound wave by the head and pinna. They could also be based on inter-aural time differences that are present because of the distance between their two ears. Moles have no pinna so they are thought to hear at low frequencies. In addition to this, their inner ear is unusual for that of a mammal due to the large trabeculation of the posterior ventral skull between the ears. The tympana of the ear lays almost horizontal and the manubrial tips are separated by a distance of 8 mm. The results of several studies confirms that there is good transmission through European mole’s head for a range of low frequencies. Because of this it is expected that there will be acoustic interaction at each tympanic membrane. The results of the study also suggest that the ears of this mole act as balanced, pressure-difference receivers. This system has never been suggested for a mammal in the past, but other reptiles, amphibia, birds, and crickets have been shown to have a direct air pathway between the tympana.
Read more about this topic: European Mole
Famous quotes containing the word hearing:
“That myth—that image of the madonna-mother—has disabled us from knowing that, just as men are more than fathers, women are more than mothers. It has kept us from hearing their voices when they try to tell us their aspirations . . . kept us from believing that they share with men the desire for achievement, mastery, competence—the desire to do something for themselves.”
—Lillian Breslow Rubin (20th century)
“Therefore I have uttered what I did not understand, things too wonderful for me, which I did not know. ... I had heard of you by the hearing of the ear, but now my eye sees you; therefore I despise myself, and repent in dust and ashes.””
—Bible: Hebrew, Job 42:3-6.
Job to God.
“Orpheus with his Lute made Trees,
And the Mountaine tops that freeze,
Bow themselves when he did sing.
To his Musicke, Plants and Flowers
Ever spring; as Sunne and Showres,
There had been a lasting Spring.
Every thing that heard him play,
Even the Billowes of the Sea,
Hung their heads, and then lay by.
In sweet Musicke is such Art,
Killing care, and griefe of heart,
Fall asleepe, or hearing dye.”
—William Shakespeare (1564–1616)