Why can't we be like fish?

[mistermack]

I honestly don't know the answer to this.
How come fish can live and be very active, with a body temperature close to freezing? And they can adjust to warmer body temperatures without dying?
Whereas my body temperature HAS to remain steady, within a very narrow band, or I die.
Apart from hibernation, all mammals seem to be the same.
And lizards can't match fish. They can't operate in low temperatures, they grind to a halt. But fish can be incredibly active in freezing water.

A trout can be highly active in water just above freezing, and also in very warm water, so long as it has oxygen.

I can't see the evolutionary reason why we became fixed on 36degC, +- a tiny amount.
Anybody know?
.

[Gawdzilla Sama]

Put a cold blooded animal on a glacier, next to a wolf. See who eats whom.

[mistermack]

Put a cold blooded animal on a glacier, next to a wolf. See who eats whom.

Yeh, but great whites feed on seals, so it can work the other way.

I just don't see why our temperatures have to be so constant, when fish just take the temp of the water, with no apparent health or activity problems.
.

[Gawdzilla Sama]

Put a cold blooded animal on a glacier, next to a wolf. See who eats whom.

Yeh, but great whites feed on seals, so it can work the other way.

I just don't see why our temperatures have to be so constant, when fish just take the temp of the water, with no apparent health or activity problems.
.

You're looking at one aspect of the situation. Hyperfocusing causes you to miss other factors.

[GenesForLife]

I'm reminded to invoke Cali & his Tropical Fish at this juncture.

[Trolldor]

[charlou]

I'm reminded to invoke Cali & his Tropical Fish at this juncture.

You said it first.

/thread

[Feck]

Fungus and enzymes we are too warm for most fungi to infect; and enzymes work better at our range of temperatures we don't have to run our engines at minimum efficiency just because the temperature is cold .

[charlou]

Fungus and enzymes we are too warm for most fungi to infect; and enzymes work better at our range of temperatures we don't have to run our engines at minimum efficiency just because the temperature is cold .

okay, so my /thread was premature

[Xamonas Chegwé]

Fish can function well in a wide range of temperatures but many are unable to cope with a rapid change in temperature. At the local nature reserve, a recent flood caused river water (which was only 7º-8ºC cooler) to run into the lakes - dozens of fish went belly-up.

[Feck]

Look at reptiles in temperate regions have to be exposed in the morning to bask and get warm ,have to hide at night to conserve heat and then hibernate in the winter .

that's a hell of a lot of their life span spent not eating or breeding .

[Thinking Aloud]

I honestly don't know the answer to this.
How come fish can live and be very active, with a body temperature close to freezing? And they can adjust to warmer body temperatures without dying?
Whereas my body temperature HAS to remain steady, within a very narrow band, or I die.
Apart from hibernation, all mammals seem to be the same.
And lizards can't match fish. They can't operate in low temperatures, they grind to a halt. But fish can be incredibly active in freezing water.

Our bodies have specialised to do other things that preclude swimming in freezing water, sadly. Those fish that do are lacking somewhat in the opposable thumbs and massively heavy brains department.

[mistermack]

I still don't get it though. what is it about 35degC that is so bad, that we shiver and use up energy, just to get back to 37, and why is 39 deg bad, and we have to sweat and waste precious water, just to cool down to 37.
I realise that we get problems with 39 degrees, like our brains can't take it for long.
But that's because we've evolved to operate at 37, it doesn't explain why we didn't just evolve like fishes, and operate ok right down to nearly freezing.
There is a price to pay, because many of our ancestors must have died of cold, or heat stroke.
So there must be a big benefit somewhere for maintaining a constant body temperature, to counteract that disadvantage.
.

[Gawdzilla Sama]

You make it sound like this was planned.

[Clinton Huxley]

We are fish, heavily modified and terribly silly fish.