Dolphins use double sonar

June 7, 2011
Credit: CC0 Public Domain

Dolphins and porpoises use echolocation for hunting and orientation. By sending out high-frequency sound, known as ultrasound, dolphins can use the echoes to determine what type of object the sound beam has hit.

Researchers from Sweden and the US have now discovered that can generate two beam projections simultaneously.

"The beam projections have different frequencies and can be sent in different directions. The advantage is probably that the dolphin can locate the object more precisely", says Josefin Starkhammar, a newly examined doctor in Electrical Measurements at Lund University, who also holds a Master's degree in Engineering Physics.

The study, which was carried out together with scientists from San Diego, was published in the latest issue of the journal Biology Letters. The co-authors of the article were Patrick W. Moore, Lois Talmadge and Dorian S. Houser, who work at the National Foundation.

"The findings add fuel to an already fierce debate in the research community on how the sound is produced", says Josefin Starkhammar.

Dr Starkhammar's own guess is that the two sound projections come from the two different sound-producing organs, the existence of which is well known, but it was believed that only one was active during echolocation. She stresses that more research is needed. For example, the two projections could also be explained by complicated reflections in the head of the dolphin, where the sound is formed.

"It is also somewhat remarkable that this has only been discovered now. Research has been carried out on dolphins and echolocation since the 1960s", says Josefin Starkhammar.

One explanation as to why the discovery has taken so long is that this research requires recently developed and quite advanced and techniques. In addition, until now it has mostly been who have conducted research on dolphins, and their expertise is often not in this specific area of technology.

Furthermore, the research requires dolphins trained to answer scientific questions! The combination of marine biologists and engineers is ideal, in Josefin Starkhammar's view.

To help her she has developed a device with 47 hydrophones (microphones for use in water).

"It is currently one of the best devices in the world for capturing dolphins' ultrasound in water", says Josefin Starkhammar, who has spent a lot of time testing and developing the equipment, including at Kolmården Wildlife Park, where one of her supervisors works. There she has also conducted other studies on dolphins and their echolocation.

Bats also use echolocation and there are a few species of shrew and some cave-dwelling birds which use a simpler form of the method. Even humans have developed devices that use echolocation and ultrasound technology.

"However, dolphins' echolocation is in many ways much more sophisticated. Evolution has had the possibility to hone it over millions of years.

Therefore, we humans have a lot to learn from dolphins. What is more, the knowledge could be important in finding ways to protect dolphins, for example from noise disturbance", says Josefin Starkhammar.

Explore further: 'Flipper' trainer against dolphin tourism

More information: The article in Biology Letters is available online:

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1 / 5 (6) Jun 07, 2011
One explanation as to why the discovery has taken so long is that this research requires recently developed and quite advanced measuring equipment and signal processing techniques.

However, dolphins echolocation is in many ways much more sophisticated. Evolution has had the possibility to hone it over millions of years

This rings very hollow right here. Just how did evolution manage to make this miracle come true? On the one hand the sophistication of simultaneous echo soundlocation requires highly advanced equipment to detect but on the other hand evolutionary processes have no way to know what is required beforehand to process any kind of sound! You cannot have a sound without the ability to process it - how would that convey any evolutionary benefit to the animal. Vice versa - how could you have receivers and decoders without the sound? The two has to be developed simultaneously - which in evolutionary terms is a miracle.
The researcher glibly says that evolution did it but doesn't offer any explanation or support for making such a statement.
This is the nonsense that results when one believes in evolutionary fairytales.
1 / 5 (1) Jun 07, 2011
this news was around at least two years ago. i tried coining a term for it : stereocholocation

not rated yet Jun 07, 2011
On the one hand the sophistication of simultaneous echo soundlocation requires highly advanced equipment to detect but on the other hand evolutionary processes have no way to know what is required beforehand to process any kind of sound!

And you obviously have no idea of how evolution by natural selection operates. I suggest you go and read a few basic text books on the subject before displaying your complete ignorance of the subject.
5 / 5 (1) Jun 07, 2011
He just thinks his inconsistant sky-fairy waved his hands and poof.

To follow what others have asked:

When was the Flood?
Why can we see stars more than 6000LY away?
5 / 5 (2) Jun 07, 2011
OK guys, I've got this one... someone else get him next time he brings up the simultaneous junk...

Kev, yet again, you refuse to read simple explanations that have been given to you ad nauseum. A trait can arise from random mutations, like generating a sound. If it provides a benefit, that feature stays. The brain, on the other hand is a general purpose signal processor. Any signals that are detectable by the brain can most likely be figured out, naturally. Brains find patterns. It's what they do. They recognize patterns and classify.

Well, I could go further about tearing apart your "simultaneous" argument, but it's not necessary here.

Kev, if the universe is only 6000 years old, why is it that we can see objects more than 6000 light years away?

Poof! I just made kev disappear. Hmmm I guess magic IS real.
5 / 5 (2) Jun 07, 2011
Kev, I know what you're doing. I grew up in the buckle of the Bible belt and went to a bunch of religious schools too and had the same training you did. Guys, they teach us that when we're "out in the mission field" (like this web site), our mission is to convert. Kev has been trained since birth to do this. He truly believes he is doing God's calling and that it's his moral obligation to save as manyh souls as possible. "Standing alone" (as in getting voted 1's) is considered a badge of honor. He probably goes to weekly prayer meetings and discusses his cases (us) in those meetings and is given encouragement that he's doing the right thing.

Kev, the problem (one of them, anyway) with your tactic is that you're doing more damage than good. Because you do drive-by comments, refuse to answer simple questions, and post the same nonsense that we disprove every time you do it, you lose all credibility as does the idea you're poorly promoting.

If you'd stop and think, you'd change.
5 / 5 (2) Jun 07, 2011
Kev, if you want your ideas to be taken seriously, then you have only one option here: ANSWER OUR SIMPLE QUESTIONS! When you refuse to do it, it gives the impression you have no answer. That's even worse than Congressman Weiner giving ridiculous responses to the simple question posed to him over and over, "Was that you in those pics and did you send them?" At least he gave a response, as ludicrous as it was... he gave one. Eventually, it became apparant to him that no one was buying his BS. You are currently like Weiner before he realized no one's buying your BS.

Man up and admit you're wrong or provide a reasonable, logical explanation for our questions to you, like this one:

If the universe is only 6000 years old, explain to us why we can see objects more than 6000 light years away. Prove to us you have any credibility, or you'll forever be a Weiner.
not rated yet Jun 08, 2011
Maybe we can start Kev's education away from his narrow anthropocentric viewpoint by directing him to this rather nice interactive graphic showing "The scale of the Universe" (http://www.newgro...525347). Here you can zoom from the scale of us humans right down to the sub-atomic scale, or right out to the scale of the whole universe. The latter will illustrate to Kev the sheer and utter insignificance of humans in the grand scheme of things.

If I can find a similar graphic to illustrate time-scales - i.e. how humanities recorded history doesn't even begin to figure in the vast desolate stretches of time we think about when talking about the evolution of life, the earth, stars, galaxies, or the universe as a whole - I'll post it here.
not rated yet Jun 08, 2011
Somehow the right-hand bracket got included in the link to "The scale of the Universe". Here is is again: http://www.newgro...w/525347
not rated yet Jun 11, 2011
There are humans (mostly blind ones) that have learned to echolocate in a primitive way. Is it so strange to think that a creature living in an environment where echolocation could give it such a large advantage develops it into such a refined level? It's more surprising the creatures that haven't developed it.
not rated yet Jun 12, 2011
I have a better explanation for 2 simultaneous sound beams. The same reason why we have 2 eyes and 2 ears maybe? 3D

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