I am just curious does the size of a ear affect the sensitivity of one's hearing?

A little. The ear's shape is to focus sound into the ear canal, and a bigger ear could focus more sound. In the old days they didn't have electronic hearing aids and they used ear trumpets (ear horns).

 

However another large part is how sound is transferred to your cochlea and how sensitive your cochlea is. Oh, and earwax.

Ah I see... But if the animal has no Pinnae[the cartilage] can it still hear well?

 

What if the animals has a Pinnae that the structure of a conch shells.

Edited August 6, 201015 yr by Mouse

No, the major function of the Pinna is to collect sound, so if an animal has no pinna, for the most part it will not be able to hear as well.

Conch shells almost all have a spiral shape to the middle of the shell, if this spiral shape is what you're talking about, then the hearing of that animal would be extremely poor, because not only would it's pinna not direct a large amount of sound towards its eardrum, the sound vibrations would also weaken as they bounced off the spiral towards the center..

Ok thanks for clarifying.

Ok but Owls and birds do not have pinnae but they can still hear. Why is that? In fact Owls can hear pretty well. Oilbirds even echolocate!

Pinnae aren't necessary for hearing, they just help it out. And owls at least often have facial discs that funnel sound into their ears.