A suggestion for dolphin communication, and an extension to SETI.

[exoscientist]

I was doing some digitizing of voice recordings when I found a surprising effect. The first zip file linked below is of a voice recording in MP3 format. The digital sampling rate was at the default 44khz. The second zipped file is the result when I applied the slower sampling rate of 8khz to the first file. <br />I was surprised to note the effect of using the slower sampling rate was to give the recording the sound of whale song or dolphin speech. <br />(Note: the post following contains a discussion of experimental evidence that dolphins do use a form of "speech".) <br />This effect is more pronounced with longer recordings. I had to shorten these to upload them to the forum. To observe this, use a program for digitally recording audio, then sample a saved voice recording at a slower rate than it was originally saved at. There are several free programs available on the net that have this capability. <br />I thought then perhaps the difficulty in interpreting dolphin speech was that we record them at a slower sampling rate than what they are actually produced at. However, it is known that dolphin speech extends into higher frequencies: <br /><br />Oceanwide Science Institute's Research Page. <br />"One of the main problems is the high frequency content of dolphin signals. Most dolphin species produce three types of signals: echolocation clicks, the faster paced burst pulse clicks, and whistles. Echolocation clicks are used by dolphins to detect and recognize objects in the water from the returning echoes. Burst pulse clicks and whistles on the other hand are thought to be used mainly for communication. Click signals are extremely short (50 microseconds) and broadband high frequency signals, ranging from 0 to over 200 kilohertz. Whistles are generally within human hearing range, but also have ultrasonic components called harmonics which can go up to over 100 kHz. However, conventional audio recording systems only go up to about 20 kHz (also the upper limit of human hearin <div class="Discussion_UserSignature"> </div>

 

[exoscientist]

******************************************<br />Newsgroups: alt.animals.dolphins, rec.arts.sf.science, sci.anthropology, sci.cognitive, sci.astro.seti <br />From: rgcl...@my-deja.com (Robert Clark) <br />Date: 20 Jul 2001 21:46:15 -0700 <br />Local: Sat, Jul 21 2001 12:46 am <br />Subject: Communicating with dolphins. <br /><br />The recent news of dolphins having the ability of self-recognition in <br />mirrors previously believed to be restricted to humans and the great <br />apes reminded me of a suggestion of Carl Sagan to demonstrate the <br />communication abilities of dolphins. <br /><br />Dolphins recognize themselves in mirror <br />http://www.usatoday.com/news/science/biology/2001-05-01-dolphin-mirror.htm<br /><br />Mirror self-recognition in the bottlenose dolphin: A case of cognitive <br />convergence <br />Proc. Natl. Acad. Sci. USA, Vol. 98, Issue 10, 5937-5942, May 8, 2001 <br />"The ability to recognize oneself in a mirror is an exceedingly rare <br />capacity in the animal kingdom. To date, only humans and great apes <br />have shown convincing evidence of mirror self-recognition. Two <br />dolphins were exposed to reflective surfaces, and both demonstrated <br />responses consistent with the use of the mirror to investigate marked <br />parts of the body. This ability to use a mirror to inspect parts of <br />the body is a striking example of evolutionary convergence with great <br />apes and humans." <br />http://www.pnas.org/cgi/content/full/98/10/5937 [full text] <br /><br />An earlier similar experiment is also available online: <br /><br />Evidence of self-awareness in the bottlenose dolphin <br />(Tursiops truncatus) <br />"Conclusion <br />"No single test presented here proves self-recognition in bottlenose <br />dolphins. The tests were developed mainly from <div class="Discussion_UserSignature"> </div>