"Dolphins send each other 3D pictures."

(From the original Avatar Course)

Harry Palmer
Did I tell you the story about the dolphins, how the dolphins perceive? No? OK, dolphins send out a sound wave and it bounces off things. They continue to send out a sound wave, and the sound wave going out bounces back and it hits the sound wave they are continuing to send out, which creates beats as the two sounds interfere with each other.

From the interference pattern between the reflected sound and the originated sound, the dolphins get a third sound with which they sonically "see" a three-dimensional underwater world. "A sunken ship over there, a lot of gold treasure over there." (laughter) "A large fish over here."

Laughing dolphin
Well, the neat thing about a dolphin is he can swim around the island and approach another dolphin, then instead of sending out the sonar sound, he sends out the interference pattern. The second dolphin, hearing it, sees images just as if he were where the first dolphin had been. It's very close to an experiential conversation. The second dolphin perceives the same three-dimensional picture that the first "saw"--a ship, fish, treasure, the same excitement--just as if he or she were there.

Harry Palmer


A well known Dutch sea biologist makes Mr. Palmer look foolish.

According to the Dutch sea-biologist Jaap van der Toorn ( this story about "advanced" communication between dolphins is not based on scientific facts. A dolphin can't send an interference pattern to another dolphin, let alone a three-dimensional picture:

"To create an interference pattern you need at least two sound-sources. A dolphin has only one sound-source. And if a dolphin could form a picture based on interference patterns (which isn't possible) even then it is impossible to generate a pattern from ONE sound-source that contains the same (three-dimensional) environmental information."

See also where Jan talks about the "fantastic-realistic qualities" Mr. Palmer attributes to dolphins.