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Comparison of marine mammals and humans

Thread Status: Hello , There was no answer in this thread for more than 60 days.
It can take a long time to get an up-to-date response or contact with relevant users.

fabrice

Well-Known Member
Apr 3, 2002
113
11
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Hello,

I'm looking for informations to do a presentation on the subject "why us mere humans are we so bad at freediving compared to marine mammals".
I'm not looking for an in-depth description of physiological mechanisms, but items like :
- some mammals don't have to equalize since their ears are filled with fluid.

Any info/pointers appreciated ! Thanks !

Fabrice
 

Adrian

Deeper Blue Beachcomber
Supporter
Nov 23, 2002
2,691
533
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Fabrice,
Do a search on mammals here. There's been quite some discussion by efattah and others on the subject, you'll find some interesting information.

Adrian
 

sinkweight

fat flotilla
Supporter
Aug 16, 2004
1,005
287
138
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Good links, Deep

Maybe somebody can now explain why I'm mistaken for a new species of Beluga.

I could stand to lose a few pounds and maybe get some sun, but C'MON!
 

Adrian

Deeper Blue Beachcomber
Supporter
Nov 23, 2002
2,691
533
218
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It's very simple Warren, it's all in your accent! Everybody knows that belugas have a good Texan drawl :) Tell me, is your avatar a reflection of how you feel after a hangover?

Adrian
 

efattah

Well-Known Member
Mar 2, 2001
3,294
487
173
The simple answer:

1. Marine mammals have a FAR GREATER oxygen storage capacity, in terms of oxygen per unit body mass, mostly due to higher blood volume per unit body mass, and higher oxygen storage in their muscles (in the form of myoglobin). Their muscles have ten times more myoglobin than humans.

2. Far more streamlined body shape allows for effortless movement through the water. Humans have a non-streamlined shape which makes swimming full of effort, wasting oxygen.

3. Marine mammals are nearly neutrally buoyant, reducing the effort to get down.

4. The blood vessels in their eustachian tubes swell with blood, meaning they don't need to equalize their ears.

5. They have a profound oxygen conserving diving reflex once they start the dive. Their heart rate slows dramatically, and blood is shifted away from non-essential muscles & organs, reducing the oxygen consumption of non-essential functions. For example, blood flow to the stomach is completely stopped during a dive. In a human, the stomach will continue digesting and burning oxygen during a dive (although the effect is diminished in expert divers).

6. The deepest diving mammals exhale before they dive, so they don't bring down too much nitrogen, and thus avoid decompression sickness and narcosis.

7. Marine mammals can withstand far greater amounts of CO2, and far lower levels of oxygen. At the level of oxygen which would cause unconsciousness in a human, a marine mammal's brain is still working fine, with clear thinking and quick reflexes.
 

Bill

Baron of Breathold
Oct 17, 2001
1,805
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There's another very important difference, sometimes overlooked. Marine mammals 'train' every day.
Aloha
Bill
 

sinkweight

fat flotilla
Supporter
Aug 16, 2004
1,005
287
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It's very simple Warren, it's all in your accent! Everybody knows that belugas have a good Texan drawl :)

Well, looking from my picture, I'm starting to see the resemblance!

as for my current avatar...it's off of a 70's childrens show called Sigmund and the Sea Monsters...the picture being of Sigmund Ooze, the main character. A crappy costume, manned by small person extraordinnaire, Billy Barty. It was part of a Sid and Marty Croft weekly special here in the states. Psychadelic morning bonanza for kids two warp their impressionable minds around on Saturdays.

I'm definitely one of the deeper-scarred kids.
 

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