What do dolphins and whales drink?

[Shakey]

Was just wondering what these animals drink.

We can't drink salt water* and other land mammals can't drink salt water 'cos of the dehydration.

So how is it marine mammals can? Or do they make up for it in other ways?



* Read a book once (Lombard Experiment??? Summat like that) about this French doctor who deliberately set himself adrift with nowt but salt water and rain water to drink and fish and plankton to eat. He lived, just.

 

[catmandoo]

Lots of fresh water in fish. In survival courses they suggest suck a fish . Whales dolphins eat fish .

Presume like fish also absorb water through skin

 

[Shakey]

That's what this French bloke did, sucked lots of fish, took as much rainwater as he could, but also drank sea water too from day one.

Just don't know how the dolphins manage it!

 

[catmandoo]

On second thoughts perhaps next time you see one you should ask it .

I used as a 15 year old boy to trawl for salmon/sea trout in the moray firth near Nairn in a canoe (with out life jacket of course)and on occcasions the local school surfaced close to me with a gasp which sounded like

" Got a dram " and since I was under age at the time I was unable to oblige as well as once having my attention diverted by hooking a herring gull at the same time which embarrassingly ended up flying like a kite at the end of my line

Their high pitched sonar however did hurt my brain

 

[BrianJ]

Cheap French wine
BrianJ

 

[Benbow]

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Lots of fresh water in fish. In survival courses they suggest suck a fish . Whales dolphins eat fish .

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But that just raises the question - what do fish drink!?

The boring answer is they just have much more efficient kidneys and can maitain a higher osmotic differential than land mammals - essentially they excrete a much saltier urine while human urine is very similar to seawater salt content. Many seabirds that spend their lives at sea can do the same.

 

[Sybarite]

Dr Alain Bombard.

 

[penultimate]

Just to notch up the boring threshold further: it's all down to osmosis.
Freshwater fishes fishes never drink. They don't need to because they absorb water osmotically through their gills and have efficient kidneys to dispose of the excess water. If transferred to the sea they die, as humans do, either of dehydration or an excess of salt in the blood. Marine species on the other hand, in a medium more concentrated than their blood, have to drink to compensate for the loss of fluid osmotically through the gills. They have "salt cells" at the base of the gills to dispose of the excess salt; and they excrete a small amount of concentrated urine. If they are transferred to fresh water they soon die from dropsy because they can't cope with the amount of water absorbed into their bodies. The really clever fishes are the salmon and eel families and (some other species to a more limited extent). They have efficient kidneys and "salt cells"; but also drink when they are in sea water and give up the habit when in fresh.
Now you know why I sail on my own!

 

[Deleted member 478]

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Now you know why I sail on my own!

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Oh Sh*t! Am I going to become veritable source of useless information?

 

[Shakey]

Thanks everyone, I can sleep easier tonight without the torment of ignorance!