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..."
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)
Knowing this number will be critical for any modelling of chipmunk energetics.
So knowing how big the cheeks are, is a useful information, but in this context not clear.
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.
To me, that's the most fascinating part of the (already quite fascinating) story. Frog is frozen solid, there is no (to our knowledge) heartbeat or brain activity. It thaws and something happens that gets it going again.
I have trouble imagining what that mechanism could even look like. Tiny portion of brain responsible for keeping track of frozen-ness? Some chemical signaling from within the body cavity?
In humans (and I guess many animals), the thing that controls the heart beat is a structure in the heart called the Sinoatrial node. Each cell in the SA node has an ability to generate its own rhythmic electrical impulse. I imagine that when one of these cells thaws out in a Wood frog, it immediately starts producing its rhythmic pulse. It has to get in sync with the rest of the cells in the Sinoatrial node before the heart will beat correctly, so the cells have a mechanism to communicate their rhythm with their neighbours. I guess each cycle, each cell adjusts its phase a little towards the average phase of its neighbours and thus a consensus will be reached.
Or the elasticity of the heart and muscles.
If the heart depends on the brain at all in frogs.
So starting and stopping the heart in a controlled manner is pretty interesting, because it has to be well-timed, and there are few obvious and reliable inputs to control it, especially when thawing.
I am fully aware that if the human heart is severed from the brainstem it will develop A rhythm.
But what about other mammals? Dunno. Not going to assume.
Theres also the tidbit that frogs are not mammals.
Maybe it is that thawing happens in reverse with the extremities, then the rest of the system thawing, with the heart being last. Would be a biological advantage in this case for the heart to be centrally located.
FTA: In spring, the wood frog thaws from the inside outward. First the heart starts beating. Then the brain activates. Finally, the legs move.
So the sequence is more:
1. Outside of frog thaws
2. ??
3. Heart starts beatingYou don't need a brain to execute "programmed behavior" in a body, the cells have enough "compute" in the regulatory networks of their DNA, RNA and proteins to do that on their own (and in fact do it all the time as part if their normal functioning. That's what "metabolism" means.)
Another question would be where the cells take the energy to execute that program if blood circulation has halted and there is no oxygen. But then on the other hand, at that point they are filled to the brim with glucose. So I wonder if this isn't just to prevent freezing but also as an energy reserve for the "restart".
(Sorry for the bad programming analogies in this post, please don't take them too literally)
"In the mid-1950s, Lovelock experimented with the cryopreservation of rodents, determining that hamsters could be frozen and revived successfully.[14] Hamsters were frozen with 60% of the water in the brain crystallised into ice with no adverse effects recorded. Other organs were shown to be susceptible to damage.[15]"
And there's a Tom Scott's interview with James Lovelock:
You have to thaw them right down to the core very quickly; you need to get the heart pumping or the thawed extremities will die with no bloodflow. There's no way to heat a human's core that fast without causing unsurvivable burns to their outside. (Even the rats wound up with nasty, sometimes fatal burns.)
Even if you had the biochemistry that was able to do this, how many cycles could a higher life form tolerate this, assuming it would even work? Complex life seems to sacrifice some resiliency, such as the ability to regrow limbs. Amphibians already seem to be particularly adept at regeneration.
If you didn't know, you need to wait to harvest maple syrup until you have a series of days when the daytime temperature is above freezing and the nighttime temperature is below freezing. This causes the maple sap to flow and allows it to collect in the bucket.
https://botanistinthekitchen.blog/2013/03/18/maple-syrup-mec...
Still scientists are working on it - they've done frogs https://www.nbcnews.com/science/science-news/can-humans-regr...
Vertebrates are animals, but not all animals are vertebrates.
A lot of invertebrates can regrow lost organs or even heads. Insects lose it for the luxury of having wings, but other arthropods can regrow lost limbs if they live for enough moults. Planarians can regenerate everything.
- New study [2]: 7 months (with 100% survival rate)
So further study seems to be needed.
[1] https://journals.biologists.com/jeb/article/216/18/3461/1160...
[2] https://journals.biologists.com/jeb/article/217/12/2193/1211...
Since chemical reactions happen in the freezer just slower...
Can't the gross just be kept at artificially lie temperatures to lengthen the stasis time? Say, -100C or even lower?
Effectively they're dead when they freeze. I'm assuming there's no brain activity.. Which means when they thaw they're being restored to life. I wonder if any other animals experience this
Also this should be relatively trivial to test.
In all cases, I still don't understand how the membrane potentials are maintained or re-constructed in the thawing phase: any pointers?
Medical hypothermia in humans (which is just a few degrees colder) is bounded not really by not by time-cold but by restoring normal temperature too quickly. It turns out mitochondria generate a lot of free oxygen radicals when going hypoxic, and restoring oxygen quickly does the chemical damage that actually causes death - so they restore normal temps over a period of hours. I'd bet that's not the only metabolic cycle deranged by hypercooling.
https://www.pbs.org/newshour/science/the-secret-to-turtle-hi...
https://wildlifeinwinter.com/painted-turtle
I have one at home in constant warm water, yet she can see the sky and decides to bruminate on her own: every year around this time, she starts napping in her under water hide for days or weeks at a time.
https://en.wiktionary.org/wiki/brumation
The verb ought to be brumate. But I guess the desire to pull it into line with hibernation is strong, this happens with lots of words. (Or was the influence from "rumination"?)
So I typed in "hibern..." to Kagi and it suggested "hibernation vs brumation". I got sniped because I'd never seen the word before. So yep, I did know. And probably would have forgotten by next week if I didn't see your comment! But now I'll remember forever, thank you.
He's not very smart but he tries hard.
The wiki also mentions that urea is produced, in addition to glucose, and both act as cryoprotectants.
I wouldn't count on it killing them. The cryoprotectants in the frog's body don't discriminate; they'll protect foreign bacteria just as well as the frog's cells.
I think it would be more interesting if it doesn't affect lifespan. It would be a really counter-intuitive result (to me).
All natural, no preservatives added, sweetened frog popsicles! Yummy!
Are we taking syrupy sweet meat? Or just a hint of it?
Bamboo is a grass and doesn't come from a tree. Palm wood comes from palm trees, except palm tree trunks are apparently a totally different type of structure than other tree trunks, sounds closer to Papyrus. No growth rings, a fiber type structure. Is Papyrus wood?
Any plant matter above a certain density? I don't think that's it. Corn stalks aren't wood.
Man, I don't know. I am certain that it must be plant matter though, so yes, a wooden frog would be a biological miracle.
My total armchair answer: It helps to think about trees as just giant shrubs.
Shrubs are considered "woody", but most definitely are not trees. There are plenty of trees which are close relatives of shrubs (like poison oak and the urushi tree).
So what's the difference between a grass and a tree? Walking the tree of life up from Poison Oak and Bamboo, we see we land at Monocotyledon and Eudicots. There's lots of non-woody and tough fibrous (i.e. woody) plans in both clades (palm trees are monocots, btw).
Wikipedia says if it is tough and fibrous and has growth rings it's wood:
https://en.wikipedia.org/wiki/Wood
So Bamboo, although coming from a grass and not a tree, is wood. Further reading down that page talks about density as a key quality of wood, and goes on to not definitively quality bamboo as wood or as non-wood but some are dense enough.
Ultimately, there's no super clean definition of wood is my take-away, between the technical and colloquial aspects. You can use bamboo in construction much like wood, if you cut off a bit of shrub and dry it out, it's a "stick" just as much as if you trimmed it off a tree. You can make paper out of all kinds of fibers.
> Trees are not a monophyletic taxonomic group but consist of a wide variety of plant species that have independently evolved a trunk and branches as a way to tower above other plants to compete for sunlight.[1]
A really, really fantastic article: https://eukaryotewritesblog.com/2021/05/02/theres-no-such-th...
But palm trees aren’t truly trees, right ? Just called trees…. They’re more of a tree like shrub? I think.
Ask it to tell me about wood that doesn't come from trees, and it tells me about palm wood. I say, but doesn't that come from palm trees? It says palm trees aren't technically trees because their trunk isn't wooden.
Anyway, with your definition palm wood wouldn't be wood, and neither would bamboo. Feels like the vegetable/fruit thing though, there just isn't a perfect answer.
https://www.healthline.com/nutrition/advanced-glycation-end-...
Edit: I can't and I'm busy. Any UK folk who can provide this for our international family?
I find it hard to grasp what is still alive about the frog. I mean, it's not dead so there must be something happening inside the frozen frog? How does it compare to a dead (and frozen) wood frog?
A dead frozen frog will be frozen completely, with all the cells having ruptured walls from their insides freezing.
They only seem part frozen - still a bit bendy when touched.
Also, space travel!
While certainly some good would come of this, imagine the unintented consequences of such an advancement, especially in a world with stark income inequality.
> Frogs can survive many freeze/thaw events during winter if no more than about 65% of the total body water freezes
Look, new rule: you write an article about frogs, you include a photo.
> syrupy sugar solution prevents the cells from freezing
So they don't freeze. This is click bait.
