Biological Miracle – Wood Frog | Hacker News Reader

Biological Miracle – Wood Frog

nps.gov

505 pointsthunderbong139 comments

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..."

"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)

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.

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.

> 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

> Nobody yet understands what starts the wood frog’s heart after being frozen and inert for the entire northern winter.

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?

I skimmed https://en.wikipedia.org/wiki/Sinoatrial_node#Function. Here's my guess at what is going on:

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.

Fireflies eventually manage to more or less sync up and they’re completely separate organisms - tiny cells with physical connections inside the body should be able to make it work.

Maybe something like a bit flip but for neurons happens in the frog's brain from the sun's radiation or something.

Or the elasticity of the heart and muscles.

If it gets frozen in a heavily contracted form, unthawing it will trigger at least one half-beat: could that be enough to restart it?

Hard to imagine that this is significant, given that the (un)thawing is likely quite slow.

Did not think that my early morning would be spend trying to imagine how thawing a frog works. :)

Good point for sure.

a chemical reaction that is sensitive to temperature.

my poor knowledge of biology says it's a deeply unsatisfying "heart beats when enough of the body has thawed for it to beat."

If the heart depends on the brain at all in frogs.

It doesn't, even in humans. There is an independent circuit of special muscle cells right on it that keeps it beating.

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.

Why doesn't my heart keep beating if my brain dies then? Or would it?

I understand that it would keep beating until you are provided oxygen. That’s my understanding understanding of brain death at least.

Probably because the brain controls breathing and so the oxygen runs out quickly

I was going to say that's silly, but I guess we need to be able to hold our breath sometimes.

"Even in humans"- thats a pretty steep assumption.

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.

The point is that whatever control a frog heart may have, it's not cerebral. It must be a very low-level circuit, which can be modulated from outside, but which remains autonomous.

What puzzles me is... it is not just the heart but the entire circulatory system.

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.

> Maybe it is that thawing happens in reverse with the extremities, then the rest of the system thawing, with the heart being last

FTA: In spring, the wood frog thaws from the inside outward. First the heart starts beating. Then the brain activates. Finally, the legs move.

The article says that, but it can’t be the normal meaning of thaw. Thermodynamically, onbiously the innermost portion of the volume is going to warm last. But in terms of the frog’s system restart order, that order makes sense.

The inside of the frog isn't actually frozen, because it's glucose-flushed.

So the sequence is more:

   1. Outside of frog thaws
   2. ??
   3. Heart starts beating

This frog is alive. It could detect that long-term thaw is imminent (say from sensors on its skin) and start some processes that produce heat around its heart.

Most likely it isnt that the heart stops or starts in response to freezing. The heartbeat signal probably runs 24/7 unless inhibited by freezing. So as soon as it thaws, the signaling bit resumes its pulsing and the rest of the heart begins to beats as it also thaws. The order in which organs thaw would be regulated by sugar levels. Remember too that at this scale frogs can absorb much of their needed O2 through their skin. A steady heartbeat isn't as essential as it is with us.

Yeah, I was wondering about that too, but on the other hand, there are possibilities:

You 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)

I'm thinking that there has to be something that is still keeping the rhythm going, maybe an extremely faint signal, all throughout that dormant period

The frog is not frozen solid.

Interestingly, you can freeze a rat solid in liquid nitrogen--completely solid right through--and then thaw them out in a microwave and they actually survive. Well, many of them survive. For a while. Okay, it's not good for the rats but it's still crazy that it works.

Where can I read more about this? If this was a fact I think people would be way more excited about cryonics. Casually browsing wikipedia suggests that we are not there yet with the ability to thawn large animals or even organs.

From https://en.wikipedia.org/wiki/James_Lovelock

"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:

https://www.youtube.com/watch?v=2tdiKTSdE9Y

Wouldn’t it be crazy if only worked on hamsters

I can't source this because I read it years ago, but I believe that there is some science that says that a major factor (not the only major factor, but a major factor) is body mass and volume. Essentially, the speed at which the core organs go from operating temperature to frozen is crucial, and it's also important for them to be deprived of oxygen when that happens. Humans are just... too big.

There are ways to adjust cooling rates... for example route the blood externally and chill it like they do in some kinds of surgery.

These experiments are exactly why people were excited about cryonics, until they realized that it doesn't work on anything much larger than a rat.

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.)

I was checking youtube to see if I could see that happen but failed - they were all about thawing rats to feed to snakes. There was however a goldfish dropped in liquid nitrogen briefly and recovering https://www.youtube.com/watch?v=wwolYFGM9pU

Maybe the system relies on average heat randomness to bootstrap again ..

Wood frogs only live 3-5 years, so they probably only go through a max of 5 of these cycles. I wonder how much cellular damage they accumulate during these cycles that they can tolerate due to short lifespans. They also have ~10,000x less neurons than a mammal.

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.

"frogs don’t freeze once and stay frozen. Instead, they spend a week or two freezing at night and thawing during the day until the temperatures drop permanently below freezing"

https://shakerlakes.org/frozen-frogs/

like maple syrup...

Or water… or anything else with a freezing point that the ambient temperature crosses at night

Oh sorry, I more meant specific to the times when you harvest maple syrup.

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...

That’s pretty cool. Is there anything else that requires a freeze-thaw cycle to harvest?

I'm not actually sure. Maple syrup is all I'm aware of.

I don't understand why we're not allowed to regrow limbs. What did that make room for in our DNA?

Some animals regenerate, some form scar tissue. It's thought that scar tissue is a cheaper and faster mechanism than regrowing limbs and has thus been selected in many cases.

If an iguana loses its tail, it doesn't just bleed until the new tail starts forming, right? Doesn't it seal up and then regrow?

Yeah it does form a clot and a thin skin layer, but it remains somewhat like a wound much longer and is easier to hurt again than scar tissue covers up a wound quite quickly.

The only animal that really does it properly is the salamander and I guess our family trees diverged before they figured that out?

Still scientists are working on it - they've done frogs https://www.nbcnews.com/science/science-news/can-humans-regr...

> The only animal that really does it properly is the salamander

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.

Can't just be the salamander. I saw an iguana regrowing its tale just last week. Geckos too. Pretty sure starfish as well.

Now I'm wondering all kinds of things about their brain. Are they capable of forming memories, and would they retain those memories after a freeze/thaw cycle?

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

Reading about them, it seems they migrate in winter (like half a mile uphill), but the adults always return to the same breeding pond in spring, so that information is stored somewhere.

I'm not surprised. There have been studies that show caterpillars retain memories through metamorphosis into a butterfly (a process that basically liquefies them).

Couldn't it just be algorithmic? Go uphill in the summer, then downhill until you hit water, you'll probably end in the same pond?

The hit rate is 100%, apparently.

I would assume that just as a computer’s storage remains intact after a restart, these frogs’ brains have internal structure, synaptic connections etc that are preserved after a freeze/thaw cycle.

That’s a bad assumption though. Based on our inability to bring brains back to life it seems very likely the better comparison is volatile memory like RAM.

As discussed elsewhere in this thread, butterflies retain some memories formed as caterpillars after every cell in their body changes drastically. They never die but they change immensely and still retain memories, so I'm not sure we know enough to say what good and bad assumptions are here.

Also this should be relatively trivial to test.

The nervous system of caterpillars is not disolved during the transformation.

Hibernate and resume.

Curious to how long the frozen structure can "survive". I wonder if it's a good idea to freeze one such frog and thaw it centuries later (an amphibian time-traveler!)

- Artificial experiment [1]: no longer than 3 months (but see disclaimer)

- 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...

If kept in pristine conditions (perfectly sealed to prevent evaporation leading to dehydration, deep freeze), is there a particular chemical needed for life that we might expect to break down first?

Since chemical reactions happen in the freezer just slower...

> 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?

The article says their cells don’t freeze during hibernation. -100C would probably freeze the cells and kill them

*the frog

It's a bit of a fantasy that we might find a perfectly well preserved dinosaur in a glacier somewhere.

Not possible - the oldest ice we've found on the planet is much less than 10 million years old. Even if some area remained frozen long enough to contain an intact dinosaur, it would be buried deeply enough and under enough pressure to just be a bit more arctic oil by now.

What about amber? Don't tell me that's a lie too

Forget the dinosaurs, we can't even preserve the glaciers themselves these days!

Evolutionarily, amphibians are somewhat simpler than mammals, they're smaller than a lot of mammals and they don't live as long, so I suspect some of this is simply that "things that aren't there". They wouldn't have as many problems with advanced glycation end products because the temperature is so low. There's at least one other ice survival strategy: antifreeze proteins. The fir tree and a variety of arctic fish have these: https://pmc.ncbi.nlm.nih.gov/articles/PMC6691018/.

In all cases, I still don't understand how the membrane potentials are maintained or re-constructed in the thawing phase: any pointers?

I think there are threads in Michael Levin's work that suggest membrane voltage potential may be able to be 'encoded' to microtubule structures and converted back into voltage potentials later. I don't think it's firmly established or understood yet but seems like a promising area for research!

Perhaps because ice forms outside cells, freezing ions in place. Even if there was a very small area around ion channels that was liquid that equalized all ion concentrations with the cell, when the extra cellular fluid thaws the original concentrations would be pretty much restored

Aquatic turtles have another brumination (hibernation) strategy. Since they breathe air, yet may get trapped under the ice for months at at time, they lower their metabolism plus have adaptations such as scavenging some oxygen from the water via rectal tissues as well as other chemical activity involving glucose and calcium.

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.

That's a word I don't know (and neither do you): brumation, invented in 1965.

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"?)

Weirdly, I do know this word and I learned it exactly two days ago because I wanted to know the technical difference between Hibernation and Sleep in Windows 11.

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.

Oops, thank you.

Our tortoise, even though he's in a very comfortable climate controlled indoor pen, tries to dig a hole every year to do the same.

He's not very smart but he tries hard.

For those thinking freezing could be an option... there's a fair bit more than just avoiding ice crystals.

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.

Couldn't you inject liposomal ATP into the bloodstream before the cooling process? Then mitochondria could simply be turned off. (I don't mean simple when I use the word simply)

There are no pictures of the frogs in this article. For pictures (of thawed and frozen frogs) you can see: https://shakerlakes.org/frozen-frogs/

From the linked video: timelapse of the thawing process: https://youtu.be/pLPeehsXAr4?t=176

They also have a wiki, but not many photos. One photo is from Quebec.

The wiki also mentions that urea is produced, in addition to glucose, and both act as cryoprotectants.

https://en.m.wikipedia.org/wiki/Wood_frog

Looks like a normal (frozen) frog to me

cant even call that hibernation. There are other knock on advantages to bieng frozen solid, it would slow down and even kill a lot of infectious microbes.It may convey a certain life extension benifit. And threre is not much behavioral adaptation needed,frog gets chilly, snuggles under a leaf,freezes solid, gets defrosted 8 months later and wakes up hungry and horny, not bad.

> it would slow down and even kill a lot of infectious microbes

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 should of elaborated, many of the issues associated with,"conventional hibernation" have to do with lethal infections aquired externaly while hibernating, damp, cold, ....mold as to the cryoprotectants ,side protecting microbes, clearly gut microbes and other internal flora ,would benifit......but ,big but, would a sneeky cryosuspension routine also include a freeze and clense cycle?, why not! and easy enough to verify,right!

I wonder what happens to the gut bacteria ? Do they also freeze and get thawed ? If so, are those bacterium also having a special adaptation, or is it a function of the host ?

I would imagine the frog's internal ecosystem has co-evolved with lots of bacteria that can also be frozen solid.

> It may convey a certain life extension benefit.

I think it would be more interesting if it doesn't affect lifespan. It would be a really counter-intuitive result (to me).

either way, or any info that could be gathered about life expectancy due to cryosuspension hibernation, is good, even a null result is data that plays into many conversations about longevity, space travel, temporary medical suspension to buy time. The fact of this type of biological process, moves the brackets quite a bit in how to think about many? all? other biological processes. Here is a little game....try and think about the world from a wood frogs perspective

> ...the wood frog’s liver produces large amounts of glucose that flushes into every cell in its body. This syrupy sugar solution prevents the cells from freezing...

All natural, no preservatives added, sweetened frog popsicles! Yummy!

I'm not even joking about this -- since frog legs are a thing people eat (taste kinda like chicken), I'm now incredibly curious what this would taste like if you "caught" these in their frozen state and cooked them.

Are we taking syrupy sweet meat? Or just a hint of it?

According to the video in https://shakerlakes.org/frozen-frogs, it's also full of urine. Not sure if any left after the cooking process.

I really expected a wood(en) frog here, qualifying truly as a biological miracle. But the wood frogs are cool as well.

Oh god. This made me wonder, what is wood, anyway? And I've just come away much more confused.

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.

What's really going to bake your noodle later is that Corn is a grass, just like Bamboo.

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.

It's worse than that. _Tree_ isn't even a well-defined thing.

> 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]

[1]: https://en.wikipedia.org/wiki/Tree

I don't know a precise definition, but wood has many origins. Wood has evolved hundreds of separate times, including at least 38 separate times just on the Canary Islands. https://www.researchgate.net/publication/341287935_Multiple_..., https://www.pnas.org/doi/pdf/10.1073/pnas.2208629119?downloa...

It's best to think of it as "tree-ing" or "to tree"

A really, really fantastic article: https://eukaryotewritesblog.com/2021/05/02/theres-no-such-th...

Wood is secondary xylem produced by growth from the vascular Cambium. (Sometimes? I think the issue is that there’s more than one definition of wood depending on context …?). Growth rings?

But palm trees aren’t truly trees, right ? Just called trees…. They’re more of a tree like shrub? I think.

Trying to learn about this through claude was kinda funny.

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.

Could such a mechanism be used for interstellar travel ?

Of the frogs? Sure!

Be careful though, if you send an all female human crew enhanced by frog genes, some of them might change sex on the way.

Only guaranteed to last for four or five months, so probably would be a very short interstellar travel

No. Article says they have 1000x sugar in their blood. When we get to 10x we tend to die.

We could replace some of the Glucose with Xylitol. Xylitol is another sugar that protects the body from Advanced Glycation End Products. AGEs are what makes glucose so dangerous.

https://www.healthline.com/nutrition/advanced-glycation-end-...

How are they thawing from the inside out?

We use glucose to generate energy that we burn metabolically to keep themselves warm all the time. I assume that the frogs can do it also partially.

this seems implausible to me based on how heat generally transfers...

Ok, this is what you really wanted: https://www.bbc.co.uk/programmes/p091w1b3

The content is not available in your location.

Ah, sorry. I'll see if I can find an alternative source.

Edit: I can't and I'm busy. Any UK folk who can provide this for our international family?

> No heartbeat. No breathing. For the entire winter, the wood frog is like a lump of hard, frigid, icy stone carved in the shape of a frog. But it’s alive, in a state of suspended animation.

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 live frozen frog has ice around it's cells. Inside the cells remains liquid because of extra glucose acting as anti-freeze.

A dead frozen frog will be frozen completely, with all the cells having ruptured walls from their insides freezing.

Someone tell Alcor about this.

One min video with some frozen frogs https://youtu.be/SSvspDZOVV0

They only seem part frozen - still a bit bendy when touched.

> Understanding how frogs can do this might provide valuable knowledge to help in the management of high blood sugar in people with diabetes.

Also, space travel!

>Also, the wood frog's ability to withstand freezing may help researchers discover how human organs used for transplants could be frozen and thawed without damage. This would increase the allowable time between removing an organ from a donor and implanting it within the recipient, which could make many more transplants possible.

While certainly some good would come of this, imagine the unintented consequences of such an advancement, especially in a world with stark income inequality.

looking at wikipedia, there is more information:

> Frogs can survive many freeze/thaw events during winter if no more than about 65% of the total body water freezes

https://en.wikipedia.org/wiki/Wood_frog#Cold_tolerance

I hope the frogs don't feel pain... Imagine getting frozen alive and extremely slowly.

The One who created it with care and compassion has arranged its pain. Perhaps it is like us waking up from sleep."

reminds me of the New Avengers episode "the eagle's nest" https://www.imdb.com/title/tt0659325/

Nicely written article. A few pictures could have made it more interesting.

Fascinating phenomena, thanks a lot for sharing!

tardigrades -> wood frogs -> ... -> humans

I now know why I require so much sugar and sweets: I am a wood frog preparing for hibernation!

Not one photo of said frog.

Look, new rule: you write an article about frogs, you include a photo.

here's an illustration of one: https://image.non.io/e9078e7d-5eb4-4787-9fe2-d7068d01a4df.we...

this was really helpful! thanks!

But the article explains perfectly how they look like. White eyes, glucose filled cells, frozen solid as a rock. Bang it against a table, it's definitely frozen. Throw it back underneath those leaves.

Like the Tree Octopus?

> wood frogs spend the winter frozen

> syrupy sugar solution prevents the cells from freezing

So they don't freeze. This is click bait.

Why does it only count if the cells themselves freeze? Also, am I still allowed to play freeze tag, or do we need to rename that?

Can't tell if joking...

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