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Ears - location of

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163255.  Thu Apr 05, 2007 7:50 am Reply with quote

Present the guests with some animal pictures, and ask them where the ears are:

Eagle Owl:

The ears are not the sticking-up tufsts you see there, which are used for displaying, signalling and attracting females. Only the males have them sticking up like this; the females' droop down.

Owls' ears are recessed into the sides of their faces, usually right at the outer edge of the circular 'disc of feathers' around the eye. This disc acts like a parabolic dish, focusing the sound waves into the ear canal entrance. The ears are positioned at different heights on each side of the head, diving the owl better vertical sensing resolution - handy for locating a mouse under cover.


Its ears are on the inside of its forward-facing knees. This gives it better directional resolution than if they were on either side of its narrow head.

(Picture researchers: I have some good cricket pictures we can use)


Sound is produced by tymbals on the dorsal anterior abdomen of the male. Sound reception is the function of eardrums, or tympana, which are thin sheets of cuticle located ventrally on the anterior abdomen, adjacent to the tymbals. The tympana are covered by a posteriorly projecting thoracic flap, or operculum (Fig. 6). Tympana are present in both sexes although they are much larger in males.

Tymbals are present only in males[/b] so only they make the loud, annoying noise.


Vogel's organ consists of a thinned region of exoskeleton (the tympanum) bordered by a rigid chitinous ring; associated with its inner surface are three chordotonal sensory organs and enlarged tracheae. At the base of the abdomen.

(See link for images)
A spider does not have ears. A spider hears with very tiny hairs on her legs (thrichobotria). She is very capable of localizing the origin of a sound by interpreting the movement of the air produced by that sound.

Snakes and fish
They don't have external ears, but do have hearing organs inside the body (maybe use this as a forfeit, although we'd have to be technically fernickety about using the word 'ear'). Sound can travel through certain areas of the skin and from there to the inner ears. In snakes, sound from the ground travels up through their jaws to the inner ear. In humans, this bit of the jaw has broken off and become our incus, malleus and stapes.

Links to otoliths.

163320.  Thu Apr 05, 2007 10:17 am Reply with quote

QIly the Bible has a comment about snakes and ears. In the KJV in Psalms we get:

58:4 Their poison is like the poison of a serpent: they are like the
deaf adder that stoppeth her ear;

So either the Bible was wonderful because they knew snakes had ears, or it was crap because they thought snakes were deaf. Take your pick.

163345.  Thu Apr 05, 2007 10:44 am Reply with quote

Hence the (faulty) expression deaf as an adder.

There's a reason adders are apparently so rare (apart from their real loss of habitat) - they have extremely acure hearing and hear your clumping feet from a long way off. They slither off out of the sun and into some thicket or other.


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