Re: Are you looking at me :-)

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Posted by Chris Anderson on June 22, 2002 at 04:40:35:

In Reply to: Are you looking at me :-) posted by Paul Stevens on June 21, 2002 at 22:48:37:

*-: First off, as John has pointed out making vibrations is not proof of hearing. Only the vieled is known to do this. Other animals may understand vibrations, sonar and radar to go with heat sensing labial pits and smell with thier tongues, but until studies show differently,animals that physically have no hearing apparatus and do not respond to sound can and should be assumed deaf. -*

While they may have no outer hearing mechanism and much of the inner workings of a typical ear are not present, there are features which would allow for a certain amount of hearing. "...the presence of fluid in the 'snail' and of tissue that acts as a tympanic membrane enables chameleonids to detect frequencies from 200 to 600 Hz." (Le Berre, pg. 25) Since this ability to "detect" low frequency sound is located in the head, where one would imagine the ears once were, it seems more than logical to assume that they are not in fact deaf but able to hear a very limited amount, although probably not very well. "Although the columella bone is developed, there is no tympanum (ear drum). Its function is perhaps replaced by auditory areas on the sides of the head behind the eyes. Thus, sound is carried through soft tissues and bones. Due to this structure, chameleons do not hear well and can only detect low-frequency sounds of around 200 Hz." (Necas, pg. 40) Again, this would indicate that chameleons are in fact capable of hearing a limited amount. "In place of the ear opening, a membrane of skin on the side of the skull called the auditory area registers airborne vibrations and transmits them to a delicate bony structure called a pterygoid plate. Embedded in tissues within the skill, the plate relays the vibration down a twisting and constricted pathway leading to the inner ear. Compared to the open pathway of the human ear, the chameleon analogue is inefficient, losing most of the higher frequencies. While the ear can register sound from 100 to 10,000 cycles per second, it senses between 200 and 600 cycles best." (Martin, pg. 28) Just because there is no typical ear doesn't mean that chameleons are deaf or incapable of hearing. To make such a superficial analysis based wholly on what we view as standard in us as mammals is a disservice to the uniqueness of these creatures and undermines their evolution. Please don't take me as being confrontational or rude as I don't mean to be but I feel that it is, at times, a major setback to think in such a way. As for the fact that they don't react to sound, maybe you just arn't giving them the right sound for them to react to. Lyle Puente tested the reaction of chameleons on the sounds of a didgeridoo and says they react a lot.
Additionally, the veiled is in no way the only chameleon known to produce these low frequency vibrations as you say. Ch. oweni, Ch. johnstonii, Ch. calyptratus, Ch. senegalensis, Ch. dilepis spp., Ch. melleri, F. oustaleti, F. pardalis, R. k. kerstenii, R. k. robecchii, R. brachyurus, R. uluguruensis, R. brevicaudatus, R. spectrum, B. stumpffi, B. superciliaris, B. thieli, B. decaryi and B. antakarana are all known to do this.

*-: Multiple housing of jax zants is frowned upon,they are asocial animals and I do take exception when advice is given that can put animals in harms way.When beginers are answering other beginners questions and the results are condoned by experienced people the fate is usually stressed out and dead chams.I've put up the disclaimers to the dangerous unclarified housing info, the rest is on your conscience.-*

I agree completely.

BTW, Jonheod, my comment about the lungs being part of it all was based on ADCHAM post number 10220 so go to the archive and check it out.
Chris

CCIC

Follow Ups:

Must be, I'm the only one standing here :-) Paul Stevens 06/22/02 (1)
- Re: Must be, I'm the only one standing here :-) Chris Anderson 06/22/02 (0)

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: : *-: First off, as John has pointed out making vibrations is not proof of hearing. Only the vieled is known to do this. Other animals may understand vibrations, sonar and radar to go with heat sensing labial pits and smell with thier tongues, but until studies show differently,animals that physically have no hearing apparatus and do not respond to sound can and should be assumed deaf. -* : While they may have no outer hearing mechanism and much of the inner workings of a typical ear are not present, there are features which would allow for a certain amount of hearing. "...the presence of fluid in the 'snail' and of tissue that acts as a tympanic membrane enables chameleonids to detect frequencies from 200 to 600 Hz." (Le Berre, pg. 25) Since this ability to "detect" low frequency sound is located in the head, where one would imagine the ears once were, it seems more than logical to assume that they are not in fact deaf but able to hear a very limited amount, although probably not very well. "Although the columella bone is developed, there is no tympanum (ear drum). Its function is perhaps replaced by auditory areas on the sides of the head behind the eyes. Thus, sound is carried through soft tissues and bones. Due to this structure, chameleons do not hear well and can only detect low-frequency sounds of around 200 Hz." (Necas, pg. 40) Again, this would indicate that chameleons are in fact capable of hearing a limited amount. "In place of the ear opening, a membrane of skin on the side of the skull called the auditory area registers airborne vibrations and transmits them to a delicate bony structure called a pterygoid plate. Embedded in tissues within the skill, the plate relays the vibration down a twisting and constricted pathway leading to the inner ear. Compared to the open pathway of the human ear, the chameleon analogue is inefficient, losing most of the higher frequencies. While the ear can register sound from 100 to 10,000 cycles per second, it senses between 200 and 600 cycles best." (Martin, pg. 28) Just because there is no typical ear doesn't mean that chameleons are deaf or incapable of hearing. To make such a superficial analysis based wholly on what we view as standard in us as mammals is a disservice to the uniqueness of these creatures and undermines their evolution. Please don't take me as being confrontational or rude as I don't mean to be but I feel that it is, at times, a major setback to think in such a way. As for the fact that they don't react to sound, maybe you just arn't giving them the right sound for them to react to. Lyle Puente tested the reaction of chameleons on the sounds of a didgeridoo and says they react a lot. : Additionally, the veiled is in no way the only chameleon known to produce these low frequency vibrations as you say. Ch. oweni, Ch. johnstonii, Ch. calyptratus, Ch. senegalensis, Ch. dilepis spp., Ch. melleri, F. oustaleti, F. pardalis, R. k. kerstenii, R. k. robecchii, R. brachyurus, R. uluguruensis, R. brevicaudatus, R. spectrum, B. stumpffi, B. superciliaris, B. thieli, B. decaryi and B. antakarana are all known to do this. : *-: Multiple housing of jax zants is frowned upon,they are asocial animals and I do take exception when advice is given that can put animals in harms way.When beginers are answering other beginners questions and the results are condoned by experienced people the fate is usually stressed out and dead chams.I've put up the disclaimers to the dangerous unclarified housing info, the rest is on your conscience.-* : I agree completely. : BTW, Jonheod, my comment about the lungs being part of it all was based on ADCHAM post number 10220 so go to the archive and check it out. : Chris

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