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Biological Miracle – Wood Frog

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503 points thunderbong | 4 comments | 15 Nov 24 18:16 UTC | HN request time: 0.66s | source
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durkie ◴[16 Nov 24 03:31 UTC] No.42153907[source]▶
A great book about how animals survive super cold winters is "Winter World" by Bernd Heinrich.

Bernd is a super fascinating biologist who really dives deep in to things. At one point in the book I think he was talking about chipmunks surviving winter, and it goes really fun on the first principles. Something like: "chipmunks have a surface area of X m^2, and need to maintain an internal temperature of Y˚C. If the outside temperature is -40˚C they therefore they need to consume Z calories per hour just to maintain body temperature. Their favorite food are pine nuts from the white pine tree. The pine nuts each have B calories, so the chipmunk will need to eat D of them per hour. How many nuts can a chipmunk fit in its mouth? Well I found a dead one and shoved pine nuts in to its mouth until I couldn't fit anymore, and managed to get 17 in there. That means..."

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1. lukan ◴[16 Nov 24 10:19 UTC] No.42155646[source]▶
"Well I found a dead one and shoved pine nuts in to its mouth until I couldn't fit anymore, and managed to get 17 in there."

That part is .. weird. What is the point except morbid humor?

Chipmunks have a food storage, so they don't store nuts in their mouth. They wake up, go to the food storage and eat and go back to sleep. They don't go outside to collect more nuts in -40°C. Maybe that was the point of that calculation, to show it would not be a good strategy, but there ain't much nuts in winter on trees left anyway.

(and the calculation above lacks insulation of the fur and their sleeping place)

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2. speerer ◴[16 Nov 24 11:59 UTC] No.42155964[source]▶
> What is the point except morbid humor?

It'll be part of the time-spent-eating calculation, I expect.

Edit: I think I found the direct quote among a trio from a Goodreads review, which gives more context [0]:

> To get a rough idea of whether the flying squirrel’s nest indeed affords much insulation, I heated a potato to simulate the body of a squirrel and examined its cooling rates.

> I do not know how many seeds a chipmunk usually packs into each of its two pouches—I easily inserted sixty black sunflower seeds through the mouth into just one pouch of a roadkill.

> Some years ago, I took on the brave, or foolish, task of measuring hornets’ body temperatures, grabbing and stabbing them with an electronic thermometer as they left their nests.

[0] https://www.goodreads.com/book/show/19954417

3. jounker ◴[16 Nov 24 15:09 UTC] No.42156811[source]▶
The number of seeds that fit into a cheek pouch determines calories transferred per trip to storage.

Knowing this number will be critical for any modelling of chipmunk energetics.

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4. lukan ◴[16 Nov 24 19:28 UTC] No.42158566[source]▶
They can also eat at the storage. Also some chipmunks have their food storage next to their bed.

So knowing how big the cheeks are, is a useful information, but in this context not clear.