
Why Elephants Don’t Explode: How Nature Solves Bigness - aaossa
http://noticing.co/on-size-and-metabolism/
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Terr_
This reminds me of an old (1928) piece titled "On Being The Right Size" by JBS
Haldane [0], which lightly touches on many different concerns related to
sizing:

> Of course tall land animals have other difficulties. They have to pump their
> blood to greater heights than a man, and, therefore, require a larger blood
> pressure and tougher blood-vessels. A great many men die from burst
> arteries, greater for an elephant or a giraffe.

[https://irl.cs.ucla.edu/papers/right-
size.html](https://irl.cs.ucla.edu/papers/right-size.html)

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Bartweiss
I'm confused by the slider task. The explanation simply says that voles eat
much more than elephants _per unit of body mass_ , but the sliders suggest
that voles literally eat more food per day than elephants.

Are the grass pictures supposed to be interpreted relative to the size of the
animals next to them?

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mrec
Yes, the article seems to be mostly a roundabout restatement of Kleiber's Law
[1]

[1]
[https://en.wikipedia.org/wiki/Kleiber%27s_law](https://en.wikipedia.org/wiki/Kleiber%27s_law)

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LeifCarrotson
> 402

> Plot twist!

> Payment required...

> This embedded plot has reached the maximum allowable views given the owner's
> current subscription.

> Please visit the subscriptions page to learn more about upgrading.

Don't see many 402s!

Also, D3 is awesome. Don't pay to show a graph, either draw it in any
visualization tool and take a screenshot for the article, or use locally
hosted D3.

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seanalltogether
Here's another fun read on why sizes matter as it relates to monster movies

[http://fathom.lib.uchicago.edu/2/21701757/](http://fathom.lib.uchicago.edu/2/21701757/)

~~~
rewrew
This is a great link -- thanks for posting!

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devy
I visited San Diego Zoo a few months ago. In SDZ's Safari park, they host one
of the biggest elephant park in North America. I remember the tour guide
mentioned Elephants are so huge that if you lay down for more than 4 hours,
there are pretty high chance they won't stand up and eventually leading to
death due to the size of their body.

~~~
readams
"Elephants in zoos sleep for four to six hours a day, but in their natural
surroundings the elephants rested for only two hours, mainly at night." [1]

[1] [http://www.bbc.com/news/science-
environment-39126993](http://www.bbc.com/news/science-environment-39126993)

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eridius
This article is interesting, but all it talks about is why big animals have a
lower metabolic rate than small ones. I wish it would have also addressed the
question of why small animals have a higher metabolic rate than big ones. If
elephants can get away with having such a low metabolic rate, why can't voles?

~~~
ufmace
That's what the article is all about. It's temperature management. Smaller
warm-blooded animals have less mass to generate heat and higher surface area
to volume ratio to dissipate it faster. They need a much higher metabolic rate
to maintain body temperature, especially when the environment is very cold.
They would freeze if they had the same rate as the elephant.

Large warm-blooded animals have more mass generating more heat and less
surface area to dissipate it. They need a much lower rate or they would
overheat. Not to mention the objectively huge amount of food and air
circulation that would be required to maintain that rate.

If either animal had the other's metabolic rate, it would be dead within
hours, if not minutes.

~~~
eridius
Couldn't smaller animals just evolve better insulation instead? Surely it
would be easier to survive if they didn't have to eat so much.

~~~
lawdog
Evolution doesn't pick the optimal solution, it just weeds out the solutions
ones that aren't good enough.

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ak217
I thought this would be about allometric scaling of organs. But if we're on
the topic of metabolism, I wonder what the rate of cancer is for shrews vs.
elephants, once the metabolism and lifespan are somehow accounted for.

~~~
tbirrell
What does metabolism have to do with cancer?

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24gttghh
Quite possibly, a lot:

[https://www.nytimes.com/2016/05/15/magazine/warburg-
effect-a...](https://www.nytimes.com/2016/05/15/magazine/warburg-effect-an-
old-idea-revived-starve-cancer-to-death.html)

[https://en.wikipedia.org/wiki/Warburg_effect](https://en.wikipedia.org/wiki/Warburg_effect)

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guelo
That was hard to read. Would have been much easier if they just got to the
point.

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jger15
Geoffrey West's book Scale gets into this -- good read.

[https://www.amazon.com/Scale-Universal-Innovation-
Sustainabi...](https://www.amazon.com/Scale-Universal-Innovation-
Sustainability-Organisms/dp/1594205582/)

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amelius
Also, at the cell level, large animals should have a better self-protecting
mechanism against cancer, because more cells means a higher probability of
cell-divisions going awry.

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transparentlabs
The difference in metabolic rates between large and small animals is directly
linked to why large animals typically have longer lifespans the smaller ones.

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eridius
Since the embedded plot isn't showing up, you can see it at
[https://plot.ly/~aatish/115/an-ounce-of-a-smaller-
creature-g...](https://plot.ly/~aatish/115/an-ounce-of-a-smaller-creature-
gulps-more-air-than-an-ounce-of-a-bigger-creature/)

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theoh
Knut Schmidt-Nielsen wrote a couple of books on this topic. Googling Bonner
and Schmidt-Nielsen together seems to bring up some surveys of the literature.

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Florin_Andrei
Volume vs area, basically.

