Help with a report please

[Eagleray]

My sixth grade student have just finished research papers. A few of my students decided on the topic of octopus. (Kiss up points?) In one paper, the student stated that octopus are deaf. I could not find any information to back this up, as a sixth bibliography isn't always 100% correct. Can anyone tell me if this is the case?
Thanks
Beth

 

[Burstsovenergy24]

Wait for SOS but I believe they are deaf. They still can sense vibrations though. Again wait for SOS to confirm or deny this claim.

 

[Jean]

Hi Beth,

That's a toughy!

According Hanlon & Messenger (Cephalopod behaviour) cephalopods are quite sensitive to low frequency vibrations (~10Hz) but there are arguements over whether or not this can be called "hearing". It's really a problem of definitions. Cephs have no air filled cavities with associated structures that can detect the pressure waves of sound! BUT the statocyst chamber and statoliths maybe able to do the job as the nerves leading off from them respond to low frequecy vibrations (called infrasounds!).

So I don't think you can mark your student wrong, especially when the scientists can't agree!

Hope this helps!

J

reference:

Hanlon, R. T., Messenger, J. B. 1996. Cephalopod Behaviour. Cambridge University Press. p. 14

 

[WhiteKiboko]

i know there's been discussion about squid, but im not sure about octos.... try the Search function to peruse the forums...

 

[joel_ang]

I think they are deaf as they don't get too shocked when I yell. It came out in a documentry too saying they were unable to hear.

 

[Jean]

I think they are deaf as they don't get too shocked when I yell. It came out in a documentry too saying they were unable to hear.

Depends on what you call "hearing" Joel, Sound is after all only vibration which we detect with hairs and a set of little bones in our ears. Cephs can detect vibration (most likely) with the statocyst chamber and statoliths much the same idea!

As for not responding when you yell? well I rather doubt your voice would vibrate as low as 10Hz, which is the "hearing" range of a ceph. There is precendent on land. Elephants hear much lower frequencies than we do, and of course dogs can hear much higher frequencies.........!

J