Extreme Biology

11 Responses to “Snail-Shaped Organ Determines Hearing”

1. Katie O. Says:
   May 5th, 2008 at 4:43 pm

   Wow, that’s really interesting, and it makes sense. In response to your first question, the animals that come to mind are dogs. They are renowned for their good hearing, so they must have tightly curled cochlea. The reason that they probably have that is because they evolved from wolves. Wolves are carnivores, so they rely on catching prey. They also generally live in wooded areas, so their vision would have been limited. Having good hearing would have allowed an individual to be more likely to survive to reproduce. Hence, they have developed with tightly curled cochlea. Another reason may be (at least in some breeds) that when some dogs were used for hunting dogs, the owners were more likely to take better care of the dogs that would find more prey and their offspring. Cool post Anna!

2. Grant T Says:
   May 5th, 2008 at 4:45 pm

   Wow, this really proves structure determines function, as Anna stated. If animals have a tightly curled cochlea, they will in turn have better hearing than an animal with plate like cochlea. It’s really a simple concept. It’s great that now they have examined the structure of the cochlea, we might be able to have a better understanding of damaged hearing, ranging from deafness to ear infections.

   Animals with tightly coiled cochlea would be mammals such as humans. Animals that have plate like cochlea would be animals such as birds and reptiles, such as lizards and snakes. Advantages in having a better range of hearing would be hearing better in order to survive in their habitat. Their pray could make quiet sounds that would help the animal sense that their predator is near. Animals with plate like hearing probably do not need extreme hearing because they can hear their predators easily

   Interesting post Anna!

3. Kt Says:
   May 5th, 2008 at 5:21 pm

   Very interesting post Anna :] but I must say, after reading this I was a bit confused. I wondered how animals with plate like cochlea could hear predators and prey without good hearing. I decided to look a little into it and decided I would research species with the plate like cochlea and see what was giving them an edge. I referred back to Anna’s article and remembered her mentioning that birds and reptiles had the plate like cochleas and I had an sudden remembrance about reptiles! Snakes can pick up senses with their tongues!!! Pretty insane, and kind of hard to believe, but what happens is they stick their tongues and kinda flick it up and down (which I’m pretty sure everyone has seen a snake do). What the tongue is doing is picking up scents from the air and ground. Then the snake rubs his tongue on a very sensitive spot called the Jacobson’s organ in it’s mouth. The organ identifies the smell and sends a message to the brain and then the snake can tell if prey or a predator is approaching.

4. Hank Says:
   May 5th, 2008 at 5:32 pm

   Wow this is an extremely interesting post! Ive always wondered about how animals can hear, but I was never able to get an answer. Humans and most other mammals have a tightly curled cochlea while snakes and most other reptiles have plate like cochleas. Snakes dont rely on sound when sensing danger, they rely on their tongue because it indicates when there is danger about while humans mainly rely just on sound. Some of the advantages to having a bigger range of sound is being able to communicate clearly, and being able to detect when someone or something is around you. Here is a great site that I found that explains not only the cochlea, but the entire inner ear. This was a great post Anna, but I do have one question. Are there any disadvantages of having a bigger range of hearing?

5. Grant W. Says:
   May 5th, 2008 at 6:50 pm

   That was a very interesting post Anna! Just as Katie said, I would assume that dogs have a plate like cochlea since they are able to hear at such high frecuencies such as the sound made by dog whistles. The advantages to having a wide range of hearing all deal with the predator-prey relationship. The predator needs a good range of hearing to be able to better detect prey so that they can sneak up on them and eventually kill and eat them. However, a wide range of hearing would be even more beneficial to an animal that is more succeptible to being the prey. It would then be able to hear more faint and far off sounds so that it could sense a predator coming to feast on it. Another animal that likely has a plate like cochlea would be a bat. This is a likely assumption seeing as dogs can detect frequencies of up to 50,000 Hz while bats can hear up to a frequency of 100,000 Hz.

   http://hypertextbook.com/facts/2003/TimCondon.shtml

   Going on to Hank’s question, I wouldn’t think there would be any disadvantages to having a bigger range of hearing as no harm could be done by hearing some more sounds than the average organism. However, I am sure that some very high frequencies could possibly harm the ear.

6. Evelyn Says:
   May 5th, 2008 at 8:43 pm

   Great post Anna; I am just learning tons of examples about how structure determines function. Like Katie said, I think dogs must have a tightly curled cochlea becuause they can hear really well and at higher frequencies. Humans have tightly curled cochlea as well, but I don’t think as tightly coiled as dogs because we sure can’t hear as well as them. Some advantages of a bigger range of hearing are being able to hear predators or preys that may be very quiet and inconspicuous. Also, what came to mind was humans or animals that can’t see very well. They tend to have a heightened sense of hearing to make up for their dumbed sense of sight, so their cochleas may be curled more tightly than those of their species with normal sight. Also going back to the snake thing that KT mentioned, some animals with plate like cochlea use other methods of “hearing”, such as sense of smell or sensing vibrations in the ground to tell if prey/predator is coming (like elephants sometimes do). Another advantage of a large range of hearing is being able to hear potential mates better. Hank posed a very good question; One possible disadvantage of a larger range of hearing is that if you are hearing too many sounds at once, you could get confused and miss an important sound of a predator because you are distracted by a colony of crickets or something. Awesome post Anna; it’s nice to know how we hear (and why mine is really bad!! )

7. Anna Says:
   May 5th, 2008 at 8:43 pm

   whoa interesting comment katie , that links basically most of biology ogether in one philosophy. The answer to hanks question i would think would be no. There may be more of a chance of getting damaged hearing though, but i am not sure if that is true. Could someone look that up. It has obviously been made clear that prey and predators are the main factors for hearing advances. But could mating calls be another reason some animals need more advanced hearing. Warning signals too. If an animal needs to warn others that there is danger and it doesnt want the predator to know it has been seen it could use a very high or lowpitched sound to call for help or tell everyone to flee the area.

8. Hank Says:
   May 5th, 2008 at 9:36 pm

   sorry hear is that site that I mentioned from above http://oto.wustl.edu/cochlea/intro1.htm

9. Lauren Says:
   May 6th, 2008 at 4:42 pm

   I have never heard the cochlea described that way Anna, great job! I agree with you Evelyn, dogs have to have a tighter curled cochlea, they have incredible hearing at a different decible level, dog whistles are always to high for human ears. Does anyone know if animals with larger ears (example: rabbits, fennec foxes, and elephants) have tighter or less tightly curled cochleas?

10. Danielle Says:
    May 6th, 2008 at 7:53 pm

    http://www.lioncrusher.com/animal.asp?animal=35&page=3

    this website talks about the wolf its great hearing abilities which is nessisary for communication(which is an important aspect of a wolf pack), hunting(also very nessisary, and all in all survival as a whole.

11. Jennifer M Says:
    May 13th, 2008 at 10:29 pm

    cool post anna, lauren i read your comment and wondered the same thing so i did alittle research and found a few websites that expain all about the cochlea and why size matters. I found out that animals like cows and elephants can hear as low as about 10 hertz, this means that one hertz is equal to one vibration per second. A sound with a low frequency will have a low pitch, such as a human’s heartbeat. A sound with a high frequency will have a high pitch, such as a dog whistle. So in fact those with large ears (animals that is) can hear quite well.

    http://www.physorg.com/news128352212.html

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