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Naked mole rats can survive 18 minutes without oxygen (theatlantic.com)
81 points by sohkamyung 217 days ago | hide | past | web | favorite | 65 comments



I guess this is kinda cool, but you have to look past the headline.

18 minutes without oxygen isn't far-fetched for humans. The Guinness world record for "longest time breath held voluntarily (male)" is a bit over 24 minutes.

So, yeah, that line in the article that says "no warm-blooded mammal can...come close to the naked mole-rat’s 18-minute record" seems to be painfully and stupidly wrong.

The interesting part is not that they survive for 18 minutes. The interesting part is that they do fine at 5% oxygen and that seemingly they (almost?) hold their breaths involuntarily after they pass out at lower levels.


Not to mention Dolphins, seals and great whales?


yup, Sperm whales can hold their breath for 90 minutes they divert voluntarily all the blood to focus in the most important organs only.


for the humans, they hyperventilated to supersaturate their blood with oxygen. the mole rat was without such prep.


I was under the impression that hyperventilating is more about the reduction of CO2 in the lungs, rather than saturating the blood with oxygen.

It's basically to fool your body into thinking you've got enough oxygen (since it's C02 buildup in the lungs that triggers the out of air signal to the brain, not the lack of oxygen).

Hence why hyperventilating for, say, free diving can cause one to black out without triggering the suffocation reflex as one returns to the surface of the water.


Perhaps the article meant it was impressive for their body size.


Why is this more impressive at smaller scale?



Put simply, smallers organisms run hotter...have a higher metabolic rate. If you've ever felt the heartbrat of a cat, chicken, or hamster youll notice that it is significantly higher than your own, thus they require more oxygen relative to their size. Interestingly, the article points out that they become someone anaerobic metabolizing fructose, which doesnt require O2, throughout the body as a source of energy instead of glucose

Many people assume metabolism is proportional to surface area based on the argument above. This idea was first proposed by Max Rubner in 1883. In the 1930’s, Max Kleiber proposed that metabolism increases according to body mass raised to the power 3/4. If metabolism were proportional to volume, the exponent would be 1. If it were proportional to surface area, the exponent would be 2/3. But Kleiber’s law says it’s somewhere in between, namely 3/4.

Its not clear which, if either, theory is correct. But both agree t


Can someone explain how the mole rats that stop breathing and are revived after simply reintroducing oxygen into the container? How does the O2 get into the animals lungs/blood stream if the animal stopped breathing?


They stop breathing, but don't die. Presumably, when whatever mechanism they use to measure oxygen concentration tells them that oxygen levels are high enough, they start breathing again.


Yes, obviously, but parent asked how!


One guess would be sufficiently positive air pressure to passively inflate their lungs. Or that they don't stop breathing completely, just almost.


Guess: diffusion?


Uh weird, they survive through glucose metabolysm instead of the aerobic pathway.. which is exactly what cancer cells do to operate with their bad blood supply. NM rats are cancer free yet live like one.


Regarding the set of things that look like cancer, I recently realized that human hair is quite like cancer. It just grows and grows and grows, seemingly without limit.

So are the fingernails.


But hair and fingernails are not alive. They are just extrusions of dead material. 3D printing, basically. Plus all hair has a growth limit after which it's discarded. Head hair of course has a longer limit than other hair.


They don't degenerate, translocate or interfere negatively (although they can curl to the point of biting back). Also these cell don't adapt.


> NM rats are cancer free yet live like one.

Well you know what they say; if you can't beat them, join them.


In addition to all of these strange features listed in the article, they're also the only poikilothermic mammal. Most of the time their body temperature is not regulated and it changes with the environment. But unlike reptiles or fish, if the outside temperature goes too high or too low, naked mole rats can switch back to normal homeothermic behavior and self-regulate the body temperature as needed. This way they can survive extreme conditions, and still when conditions are right they can save a lot of energy and survive long periods of hunger without going into hibernation.


Id always thought they werr just cold blooded. This is so much more interesting!


Can't some whales go hours? I mean these guys are still strange, but this headline is terrible.


Yeah, sperm whales can do 90 minutes and the longest recorded beaked whale dive is over two hours.

Heck, the human record is something like 20 minutes, by some free diver.


To clarify, the static apnea record breathing normal air beforehand is just under 12 minutes.

The record you are referring to involves breathing pure oxygen beforehand, is 24 minutes, and is nonetheless amazing.

https://en.wikipedia.org/wiki/Static_apnea

I'd always thought the egg laying, electrolocating Platypus was the strangest mammal:

"The platypus feeds by neither sight nor smell, closing its eyes, ears, and nose each time it dives. Rather, when it digs in the bottom of streams with its bill, its electroreceptors detect tiny electric currents generated by muscular contractions of its prey"

https://en.wikipedia.org/wiki/Platypus


FWIW geckos need quantum mechanics just to walk.


...and I, for one, welcome our new platypus-gecko hybrid overlords!


Don't sharks do this, too?


Yes, using the Ampullae of Lorenzini in their snout.

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


Too cool. Thanks!


Wales go without breathing, not without oxygen. I'm not sure which category this fits into but it soudns like they just about die but then revive:

> But naked mole-rats? Although they lose consciousness after 30 seconds, and their heart rates crash after two minutes, and they stop breathing entirely after seven minutes, they can survive for a ridiculous 18 minutes.


I thought the egg-laying, duck-billed, beaver-tailed, otter-footed, electrorecepting, venomous platypus was the strangest mammal.


Naked mole rats are very interesting, if I remember correctly, they behave just like social insects (bees, termites, ants, etc.) in many ways, but they're mammals.


Picture a snake trying to invade the naked mole rat tunnel system. There is almost no oxygen.

Maybe normal parasites also die from lack of oxygen.


They metabolize fructose, rather than just holding their breath. And they can survive for over 5 hours in a low oxygen environment. https://m.phys.org/news/2017-04-naked-mole-rats-oxygen.html


Humans are gonna need this soon with how climate change is going..


Why do people do such things or even talk about such stuff? This is so depressing that such experiments are conducted to just know the fact how long a rat can survive :(


The state of medicine today is built on top of similar experiments. Countless people -- yes, people, not just animals -- have died for us to discover so much about the human body and its inner workings. It's unfortunate that most people are either oblivious to this fact, or simply take the immense work going on behind the scenes for granted. Keep this in mind next time you visit the hospital ;)

Performing this experiment could have far-reaching implications. Perhaps it ends up helping scientists understand whether or not such an adaptation could transfer to humans. Or maybe it ends up being crucial in helping us understand the function of a seemingly unrelated process in the human body.

It's important to note that ethics committees nowadays are extremely strict when it comes to using live subjects, humans or otherwise, so rest assured that the experimenters did their best to minimize the suffering of the rats. If they didn't, their work would probably never be accepted for funding and/or publication.


When you talk about people dying for science is it Marie Curie and the radiation poisoning, or Nazi's testing hypothermia? One is someone boldly (of her own volition) pushing the bounds of science, the other is an oppressive group performing horrendous experiments. Perhaps cancer patients on the verge of death opting for a potentially life extending drug?

When humans test on humans (in modern societies where things haven't gone horribly awry), care is given as to whether it's safe for the individual and would help them. Consent is a big word you'd never hear in an animal study. Animal testing is weighed against what benefits "science" in some way and some sort of "unnecessarily cruel" metric which doesn't seem to account for much. Anecdotally, my girl friend is a neuroscientist and has heard about things going on in labs that would make your skin crawl. One study that came to mind is on rats defending their territory based on how much food they were given, led to rats basically ripping each-other apart on camera.

We say these things are okay, and important, but when I think that almost 13,000 animals were killed, beagles, cats, monkeys, rats, just so we could have splenda, I think that whatever we value non-human life at must be so trivially small.


What I had in mind were the people who volunteered for experimental medical procedures. Transplants, blood transfusions, neurosurgery, skin grafts, etc. The techniques were only perfected through the suffering and death of a vast number of nameless people.

> Animal testing is weighed against what benefits us in even the slightest way and is some sort of "unnecessarily cruel" metric.

> We say these things are okay, and important, but when I think that almost 13,000 animals were killed, beagles, cats, monkeys, rats, just so we could have splenda, I think that whatever we value non-human life at must be so trivially small.

That is a deeply philosophical argument. We can obviously agree that -- all things being equal -- a human's life is worth more than an animal's life. But exactly how much more valuable is it? Can we accurately quantify how many mice can die so one human can live? Does it depend on the animal and its intelligence, at least as we perceive it? The questions can go on and on with no end in sight.

Now, I'm honestly not intimately familiar with what goes in the life sciences, particularly when it comes to experimenting on live subjects. Nonetheless, I am convinced that modern ethical standards are a good way to set universal limits to what can be done to animals in a laboratory setting, while also ensuring that we as humans benefit from the results. The alternatives would be either to delay the discovery of new procedures because we don't want to hurt animals, or to just experiment on humans directly. Neither of these sounds like a better option to me.


> That is a deeply philosophical argument. We can obviously agree that -- all things being equal -- a human's life is worth more than an animal's life.

Normally I would agree, but, for example, if there is news that an Elephant trampled a poacher to death you won't find many readers rooting not for the animal.


I think splenda is a good example, in the end after killing thousands of animals to approve it people discovered it can actually cause weight gain[1]! Kind of destroys the original reason for it.

That's the thing with models, they're just models and ultimately they will have flaws. We rely heavily on animal testing and have built up reasoning to say why it's right, and that it helps, but we also don't know how much it hurts our own science with ridiculous blunders like that. Another recen inflammation, and they've been used for decades![2]

That being said, do I think science would progress slower without animal testing, or just far less and safer for the animal testing? Sure, probably, but it's worth the cost, and we'll get some benefits with less horrible blunders by relying on models. Another example, science could progress a lot faster if got rid of safety laws to test on humans, but somethings are just wrong so we don't do it.

[1] https://www.forbes.com/sites/quora/2016/09/08/the-awful-trut...

[2] http://blogs.sciencemag.org/pipeline/archives/2014/08/08/mou...


Wow, looks like I accidentally a secente there and I can't change it.

> Another recent study showed that rats handle inflammation very differently than humans, making lots of past research useless and they've been used for decades![2]


> We can obviously agree that -- all things being equal -- a human's life is worth more than an animal's life.

No, not at all. Ethics are relative. Sure, this is the a generally accepted opinion in our society, but so was slavery.


This is honestly one of the weirdest statements I've ever heard. Are you actually comparing the impact of slavery to the use of animals for research purposes? Please tell me that I misunderstood that.


I believe they are saying times change and some things that seem fine to most of the populous currently seem monstrous later. It's a lot easier to dismiss if you interpret it as you did, though.


Well, the GP mentions moral relativism, so it's no so farfetched.


Here's another view of what goes on in life sciences:

https://academia.stackexchange.com/questions/67897/i-dont-wa...

It's far too easy to ignore the atrocities in our system.


We (in the US) killed 28 million cattle for beef in 2015[0]. Just cause we like the taste of beef.

I gotta be honest, 13,000 animals for a common food product is pretty much a drop in the bucket. Amortize Splenda's animal cost over a 40 year usage timeline against beef, and you're talking 0.001%. (And would drop rapidly if I included chickens, pork, and fish.)

[0] http://www.beefusa.org/beefindustrystatistics.aspx


It's not just the taste though, it's a pretty good price to protein ratio. If we didn't kill animals for protein, it'd be a lot more expensive to get.


Not really. For example, one serving of black beans has as much or more protein than your average hamburger patty, and black beans are cheaper than meat in most places.


Ground beef has 0.26 protein to weight ratio, while pinto beans have 0.22.

About 440g of pinto beans for $0.8, so about 120g/$1 for protein.

Ground beef according to Google factoid was $4/lb in mid-2015, so about 30g/$1 for protein.

It sounds like beef is already an expensive source of protein.


I'd say it's all awful, one being worse doesn't make the other better.


>I think that whatever we value non-human life at must be so trivially small.

If you want to depress yourself further read about the "Great" Emu War.

Not to be a debbie downer, but a lot progress, especially pre-20th century is built on human misery and suffering.


But none of that really justifies animal experimentation.

> It's important to note that ethics committees nowadays are extremely strict when it comes to using live subjects, humans or otherwise, so rest assured that the experimenters did their best to minimize the suffering of the rats. If they didn't, their work would probably never be accepted for funding and/or publication.

I don't buy it. These ethics committees are starting with the presumption that it's ok to use animals in experiments to begin with. Have they outlawed vivisection yet? I've talked to a researcher at a large US state school who routinely sawed through monkey's skulls and installed removable, screw-on skull caps so that they could poke and prod at their brains more easily.

I mean, I'm a hypocrite for saying that though. I still eat chicken. But I don't delude myself about it.


If you don't think it's an effective system, propose an alternative.


I'm not talking about whether it is effective or not. If you want a maximally effective system, do away with ethical considerations altogether.


That's exactly my point. The alternative is to either throw all ethical rules out of the window or to never experiment with any living being for any reason whatsoever. What we have right now strikes a good balance between the two, at least the way I see it.



No kidding. What a sad experiment, to deprive an animal of oxygen and see how long until it stops breathing.


Maybe you missed the part where they say that these animals naturally live in oxygen-deprived environment in their nests? They stop breathing because they evolved to do so in those situations. Would you say it's sad to freeze carp to see at what point they stop breathing, even though carps naturally do that every winter?


What would be an alternative way to learn this that would be more acceptable to you?


Do they have to be naked for this?


Yes they do. If they had fur it would be another specie so wouldn't work.


No but it helps get clicks.


How long can they survive when dressed?




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