Extinct goat was cold-blooded (2009) | Hacker News Reader

Extinct goat was cold-blooded (2009)

phys.org

169 pointssamaysharma100 comments

We still have one cold-blooded mammal species around[1]. And a few marine fish species that are partially[2] or fully warm-blooded[3].

[1] https://en.wikipedia.org/wiki/Naked_mole-rat

[2] https://en.wikipedia.org/wiki/Swordfish

[3] https://en.wikipedia.org/wiki/Thunnus

Huh. TIL tuna fish are warm blooded.

Bluefins can generate so much heat in their bodies that their muscle fibres denature. Sometimes this happens while stressed on a fishing line, for example.

Some lizards are (somewhat) warm-blooded as well: https://www.science.org/content/article/world-s-first-warm-b...

Some days ago there was news about some researchers predicting mammals would be doomed by the next supercontinent cycle, due to too high temperatures incompatible with warm blooded creatures. Well, if mammals can just evolve back cold blood, perhaps that makes their thesis moot. See https://news.ycombinator.com/item?id=37654289

Mammals have adapted to adverse conditions before. However, the current rate of change is unprecedented. Evolution does not happen in one or two generations.

when evolutions happen, they do happen in one generation, that's where new clades are formed

A mutation happens in one individual in one generation. Evolution happens when that mutation propagates through the population by reproduction. That itself takes many generations. Not to mention the fact that the mutation needs to be both advantageous and be recognized as such.

Evolutionary bottle neck events don’t work in such a polite and calm fashion, and there have been many of them.

What happens is 90% of the population (or often more like 99.999%!) that don’t already happen to be carrying an advantageous mutation perish. Sometimes the whole species goes extinct if there is no such mutation already there.

The remainder, if there are any, then don’t have to worry about as much competition, and rapidly reproduce to fill the now mostly empty niche.

Sadly the gene has to give some advantage to its bearer to actually spread in the population. With only future benefits, i does not spread.

This is not true, it can spread. It's called neutral evolution.

It might also just as well disappear again. It's random after all, and when that happens we call it genetic drift. However, it's rare for a gene to be truly neutral.

> Evolution happens when that mutation propagates through the population by reproduction.

Evolution happens when the distribution of genes in one generation differs from the distribution of genes in the previous generation. It happens every generation without fail.

A significant number of mammals have generations every year (or less).

There are observed cases of very rapid adaptations occurring.

Yes, there are annual plants that evolve significant adaptations to avoid water loss within five generations (5 years), in response to drought. Things like having smaller flowers, flowering earlier in the spring, and smaller leaves. Many plants also have a lot of phenoplasticity that allows them to adapt without genetic (evolutionary) change.

Glad to hear we can carry on as usual without worrying about completely destroying life on the planet.

Yes, the planet and life will survive us

In the last couple of years I've been thinking more often about a Venus scenario where life does not survive. We are just hoping that life will find a new equilibrium in the next couple million years like it has in the past. But if temperatures rise too fast, the planet will just get cooked before enough CO2 will be sequestered. The great filter is still in front of us.

I mean, we have bacteria living off of the heat and gases of underwater volcanoes — it is absolutely not realistic to think that life itself will be in jeopardy. It has survived the release of a highly reactive gas that killed off the majority of things (oxygen), a huge meteor that introduced a huge cooldown overnight, etc.

Of course, it doesn’t mean that we should not try to stop the impending doom that will kill off an insane amount of species, and render many populous places unlivable for humans, causing famine and wars - but Life itself will never be in any danger.

I thought so too at first. But there is no liquid water on Venus. So it is possible for all life on earth to just get boiled off.

The Venus is quite a lot closer to the Sun, though. A few degrees C change in the average temperature of the Earth indeed can cause absolute large changes, potentially killing of most more complex life forms, but even that would be very far off from the point where life is infeasible - especially that the bottom of the ocean won’t be reaching anywhere close to temperatures where proteins denaturate.

Venus gets roughly double the sunlight that earth does, also:

“Conditions possibly favourable for life on Venus have been identified at its cloud layers, with recent research having found indicative, but not convincing, evidence of life on the planet.” https://en.wikipedia.org/wiki/Venus

https://www.climate.gov/news-features/climate-qa/whats-hotte...

See, in particular:

http://www.climate.gov/media/11332

We have a long, long way to go before Earth could be considered hot by historical standards. The IPCC worst-case warming scenario, where we do absolutely nothing to curtail global warming, puts us back at the midpoint in 2100.

From the first source:

Our 4.54-billion-year-old planet probably experienced its hottest temperatures in its earliest days, when it was still colliding with other rocky debris (planetesimals) careening around the solar system. The heat of these collisions would have kept Earth molten, with top-of-the-atmosphere temperatures upward of 3,600° Fahrenheit.

The second source is a chart going back 500 million years.

How is that related to IPCC projections and climate change, which are about the environment humans evolved to survive and thrive in - physiologically over 7 million years (when we had the last common ancestor with chimps), culturally and technologically over 10 thousand years.

I’m responding to the comments about the extinction of life on Earth, not the extinction of humanity. As you can see on the graph, for most of the last 500 million years the Earth was hotter than it is now, and obviously there was life.

I was not referencing the first couple paragraphs of the linked article, since obviously the first few million years of Earth’s existence are irrelevant, and they’re the same source, which tells me you did not actually read the article; please read through next time and respond charitably rather than assuming I’m some kind of crank. I would appreciate it if you read to understand rather than to respond. It’s very frustrating when people replying to you assume you are saying something completely different rather than reading what you said within its context - a Venus scenario wiping out all life. HN commenters should do much better. This isn’t Reddit. Your entire comment is premised on me saying or thinking something I never suggested or implied.

It’s true that humanity has survived during hotter and colder periods, but certainly nothing like that depicted on the 500mil graph, and anyway industrial civilization is obviously much more fragile.

If you stick with the text of the GP, none of what you say is there. Have a good day!

Click the parent link on my post.

This is the full text:

> In the last couple of years I've been thinking more often about a Venus scenario where life does not survive. We are just hoping that life will find a new equilibrium in the next couple million years like it has in the past. But if temperatures rise too fast, the planet will just get cooked before enough CO2 will be sequestered. The great filter is still in front of us.

Clearly, even a rapid return to the projected IPCCC 2100 worst-case numbers will not cause this scenario. Would it be deleterious for advanced industrial civilization? [1] Yes. Would it continue to be part of the mass extinctions we're causing? Yes. Will it "cook the earth" or "boil the oceans" as he suggests downthread? No.

[1] And so are a lot of other things. Whether people like it or not, advanced industrial civilization is unsustainable with or without climate change.

I've sometimes wondered if Venus' runaway greenhouse had been caused (presumably unintentionally) by intelligent Venusians in the distant past, how could we find out? What bio- or techno-signatures would we still be able to find? And what possible such signatures would be easiest to look for given the inhospitable conditions?

Humans (on the most basic level) have a much better adaptations to survive hot climate than cold.

Perhaps the plight of humans may be more conditional by the climate’s impact on farming and food supply than on clothing.

In a catastrophic climate change scenario Humans generally don't die because of heat, but because other humans throw bombs at them to get at their farmland.

Seems a bit dangerous compared to planting something else and trading.

In that scenario, humans with barely enough farmland to feed themselves are going to trade food against non-edible crops. Then the traders will be bombed by the humans now starving because their food was taken away, and you have the same situation except more local.

Not all land will grow food. We've invested our food growing capital where it's grown throughout the history of agriculture (about 10,000 years).

Good luck trading for enough food when your former high yield farmland only allows for light goat herding or poverty crops now because the glaciers that you relied on are no longer there and your aquifers are empty.

Also malnutrition and thirst, lack of assets to provide things like health care, heat, and more.

I'll take that any day over 2km thick ice cover. The closes homo sapiens ever got to extinction was 120k years ago during the last ice age.

Is changing climate a challenge? Of course it is, for every living being that got used to the status quo. Being desperate about it is the opposite of what we want to do as desperation leads to stupid decisions (geoengineering, rapid one sided deindustrialisation etc).

How are the consequences of an ice age related to current climate change?

Instead of dismissing other ideas - what should we do?

There there were a lot of scientists in the 70s and 80s predicting collapse of food production, who weren’t slightly wrong but spectacularly wrong.

The last few decades has seen an exponential reduction in poverty, and the largest increase of food production in human history (It’s a statistical fact). To predict that will suddenly reverse is a heck of a bold claim.

It's a bold claim that is also scientific consensus. See for example this summary of the IPCC report: https://time.com/6152615/ipcc-report-climate-change-agricult....

But I won't be able to convince you with that, since you probably already know it, but choose to think happy thoughts instead.

The next supercontinent is expected to form in about 250 million years. Plenty of time for mammals to evolve, if we don't wipe all the other first.

Turning to cold blooded probably doesn’t, but evolution most certainly occurs in a generation. It may mean all but a few who manage to survive die but those are the ancestors of the new species

No, mutation or recombination does happen in one generation. Then it has to spread and that needs quite a lot of generations. Mice can have a successful gene spread out in 20-30 years in a local population, humans need a thousand years for the same.

That argument is only true for humans and other "long" lived species. For example look at at how much canines have evolved in the same time span that homosapiens have stayed relatively "static".

Long and static, in very very relative terms, of course.

If you mean dogs — they were bred by humans for that purpose, that operates very distinctly from “raw” evolution.

The latter is not particularly fast at adopting, it survives mostly by having a huge variety in the first place, and in an adverse environment some will survive, quickly growing in numbers due to the abundance of resources left behind by other former competitors. But that only works if the adversity is not too extreme, at least in case of more complex life forms (plants, animals).

Does that mean it can’t? I know at least a few people who are especially sensitive to heat and cold. It seems likely there are folks out there who could continue to survive environmental changes given our population, just not as many as currently exist.

Our population is as high as it currently is because of technology. Without technology, it is not possible to sustain and feed people in cities.

Or in fact in most habitats humans have colonised within the last hundred thousand years. People forget that fire, spears, clothing, constructed shelters, etc are technology.

This prediction isn't about climate change, it's about the formation of a new super continent. Because it'll be such a large landmass, and the energy from the sun increases by about 1% every 100 million years, the inner parts of this continent are predicted to be too hot to support most life as we currently know it. Of course, who can really say what will happen / evolve / be there by that time anyway?

Not sure this makes sense unless that super hot and dry inner landmass doesn't look like deserts we have today.

Desert animals will thrive there, but I doubt most mammals will evolve to adapt to that environment...

A large asteroid hit the Earth and lead to rapid unprecedented change. Yet here we are.

Dinosaurs and Birds don't had any problems with high temperatures.

If dinosaurs (birds) can be warm-blooded, I guess mammals can be cold-blooded too.

They have the same problems as mammals with high temperatures, but at higher temperatures, because their normal internal temperatures are higher than those of mammals.

Lindy mammals?

There are bison on Catalina Island, left there by a film company around a hundred years ago. They are smaller than bison on the mainland:

“They’re very challenged healthwise when they’re on this island because they don’t have the adequate nutrition during the right time of year,” King said. “So, our bison are in fact a little smaller than the mainland, and it’s not a genetic difference. It’s due to not having the right nutrients at the right time.”

https://www.voanews.com/a/history-catalina-bison-hollywood-t...

The article also notes that bison from the island were relocated back to the mainland on three separate occasions to try to reestablish herds here. I can't currently find a citation, but I recall reading that bison that were returned to the mainland put on weight.

It's well established that island populations of animals trend physically smaller. That part isn't at all news.

> It's well established that island populations of animals trend physically smaller.

Big animals trend smaller (https://en.wikipedia.org/wiki/Insular_dwarfism), and small animals trend bigger (https://en.wikipedia.org/wiki/Island_gigantism). Hence the giant rabbits on Menorca that these goats outcompeted when the islands were connected (https://en.wikipedia.org/wiki/Nuralagus).

Just because their bones grew in cycles like reptiles, does that necessarily mean they have to be cold-blooded too?

I wondered that too. I wonder if you see similar bone growth patterns in hibernating animals?

Well, debunking the myth that extinct goat was cold blooded will be a great subject for articles in the future!

It became extent only 3,000 years ago?! Can we assemble a genome?!

No such thing as hot or cold blooded.

You have:

    Endothermic: Generating internal heat to moderate body temperature, e.g., modern birds and mammals.

    Ectothermic: Relying on the environment and behavior to regulate body temperature, e.g., typical reptiles.

    Homeothermic: Maintaining a constant internal body temperature, e.g., modern mammals, birds, and some others.

    Poikilothermic: Having a fluctuating internal body temperature depending on the local environmental conditions, e.g., typical reptiles and actinopterygiian fish.

Looking at only what you presented, it seems like Endothermic/Homeothermic share a lot of overlap (hot blooded) and Ectothermic/Poikilothermic share a lot of overlap (cold blooded)?

I think endo/ecto are mechanisms and homeo/poikilo are results. They mostly match up (why spend all that energy generating body heat if you're not going to use it to maintain a constant maximally-biochemically-effective temperature?) but not 100%. An ectothermic-homeothermic animal would have to put more effort into using the environment to maintain a constant body temperature. Google says there are some lizards in that category.

I guess the distinction would be that hot and cold are quantitative. There are "cold" blooded reptiles that love temps well in excess of 120 degrees.

Huh. Is the evidence mostly bone growth patterns? That certainly seems likely to follow metabolism... but it does make me wonder what the difference is compared to hibernating mammals. (Much) longer periods at each rate? Something else?

Yes, it is a huge jump to assume the were cold blooded, rather than slow growing, or seasonal depending on the plants they ate. There's a lot of mammalian metabolism that stops working at room temperature.

Bears, and some other mammals, hibernate during which their metabolism drops. Any reason to believe this isn't just an exaggeration of that? It just seems really hard to believe actual cold bloodedness could appear like that. Why wouldn't lizards colonize the island instead?

I would suggest that it's best to think of it as the exact opposite, mammals came from ectothermic ancestors, and gradually began to develop what could be considered "extreme hyper-metabolic states" in comparison, which offered various advantages (denatures the proteins in many microorganisms, allows for consistent physical performance and activity at night when when most of the reptile predators were inactive) at the cost of needing a much higher and constant food/energy intake, and began to spend most of their time in such a state until it became "normal". However many mammals still require the ability to enter significantly lower metabolic states to survive every winter.

A good example is Golden Mantle Ground Squirrels for example, which need to consume enough omega-6 PUFAs (I believe linoleic acid is the primary one involved here, not sure about the others) in order to activate a switch in metabolism that ultimately drops energy use and puts them in a feedback loop to keep them there. [0] They'll periodically have rises in metabolism followed by some activity, and then drop back down into torpor throughout the winter. Squirrels that fail to kick off this change strongly enough are at big risk of burning too much energy and failing to survive the winter. Far less extreme and more well known are bears who also undergo significant fatty acid content changes. [1] Of course, metabolism is hideously complicated, and is effected by things like sunlight (touches vitamin D related pathways, among other things), vitamins (B vitamins are particularly notable) and fatty acids, proteins and carbs which all have have their own individual effects which can change in magnitude or even result in the reverse of what they "should" be doing. Look at this fucking shit and despair of ever trying to make a single correct context independent statement.[2] A perfect example I just found while looking up the other study is that while golden mantle ground squirrels appear to require linoleic acid to enter torpor, this study found that removing linoleic acid 19 days prior to hibernation enhanced how deeply they entered torpor. This isn't surprising to me, because I've heard of the possibility of linoleic acid being potentially exothermic in unusual circumstances, like extreme amounts. So laying off it once the cycle has started may allow the various feedback loops in place when monounsaturated fats run the show to more strongly express [3]

I personally consider all mammals as retaining echos of our cold blooded heritage and capable of enter lower metabolic states, both daily and seasonally (to a widely varying degree) depending on the aforementioned very complex set of conditions. This study seems to agree with me. [4] So I also personally find it quite plausible that if evolution begins selecting against the hypermetabolism that was adopted, then the genetics are still ready and waiting for re-emergence, especially on an island where disease pressure is going to be much more limited. Evolution seems to like adding and repurposing things we already have, adding layers upon layers and rarely ever actually removing things.

As for why lizards wouldn't dominate the island, there were and still are lizards present, unlike the goats who didn't manage to evolve back into lizards fast enough to escape notice by humans and thus extinction (though a quick search seems to show that many lizards on the island are also considered endangered). That said lizards are generally predators/omnivores, whereas the goats are herbivores, so they weren't likely to be strongly competing for the same niche.

[0] "The Influence of Dietary Fatty Acids on Hibernation by Golden-Mantled Ground Squirrels (Spermophilus lateralis)": https://www.journals.uchicago.edu/doi/10.1086/physzool.65.5....

[1] "Lipidomics Reveals Seasonal Shifts in a Large-Bodied Hibernator, the Brown Bear": https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6474398/

[2] Metabolic pathway charts:

- The famous Roche chart: http://biochemical-pathways.com/#/map/1

- Hand assembled map of the above https://faculty.cc.gatech.edu/~turk/bio_sim/articles/metabol...

[3] Short-Term Variations in Diet Fatty Acid Composition and Torpor by Ground Squirrels: https://www.jstor.org/stable/1383506

[4] "Daily torpor and hibernation in birds and mammals": https://onlinelibrary.wiley.com/doi/10.1111/brv.12137

PUFAs also drop body temperature in humans, afaik via suppression of the thyroid. Avoid them if you can.

Yep, it was my own personal issues that got me interested in the topic to begin with. My body temperature had dropped to 96.5-97.5 degrees F for a while. Now, excess omega-6 wasn’t my only issue at the time, but it was definitely something I didn’t need to add to the pile. I’m not currently familiar with potential thyroid effects, mine was “normal”. Though I’m not sure if that’s “it’s normal because everyone is fucked” or actually optimal. I’m more read up on the individual cellular activity, though I’m not a molecular biologist by any means.

To add to the warning: Keto/carnivores beware, pork and chicken fat in the west are very likely to have high omega-6 because of what we feed them. They can have linoleic acid content that even rivals or exceeds vegetable oils. Ruminants like cows don’t seem to have anything close to the same issue, likely protected by their large bacteria filled stomachs.

> Myotragus survived on the island as dwarf cold-blooded animals for millenia because they had no natural enemies, but they could not survive the predation of humans when they arrived on the island about 3,000 years ago.

One more thing killed by humans.

Don't be fooled, animals and other organisms happily extincted each other throughout all the history of life. We just have less data about them.

Very unlikely. needs better proofs

... and they need also to review the concept of fibrocartilage, that shows very similar rings, in animals not suspicious at all of having a reptilian metabolism or cold blood (Like, for example: humans).

The main problem could be trying too hard to milk a poor sample. If this animal was cold blooded, why the other goats and sheep living in bad places didn't developed a similar system? We have lots of sheep races selected for very poor environments. We fully explored their different genetic possibilities... nobody has seen a "crocodile like" sheep in the whole planet

> The bones of warm-blooded animals show uninterrupted fast growth, while the bones of cold-blooded animals have parallel growth lines showing interrupted growth corresponding to growth cycles, rather like the rings seen in tree trunks. Growth and metabolism rates are adjusted to suit the amount of food available, whereas warm-blooded animals require food to be available continuously. The Myotragus bones showed the same interrupted growth as reptiles.

Or the goat skeletons had regular periods of interrrupted food leading to regular harsh starvations which left patterns on the bones, maybe?

Yes I'm sure the experts didn't think of the first idea to pop into both of our heads when they published their scientific paper in PNAS. https://www.pnas.org/doi/full/10.1073/pnas.0813385106

However I'm more curious how a skeleton eats, can you elaborate?

Ok, I did what I criticise others for doing, being the armchair critic. Taken on the chin.

As for the goat skeleton, it eats when the goat eats, you know what I was saying.

> As for the goat skeleton, it eats when the goat eats, you know what I was saying.

I'm not sure why, but this conversation reminded me of this old video. What a trip down (bizarro) memory lane.

https://youtu.be/WQO-aOdJLiw

Please make your substantive points without being snarky.

This is in the site guidelines: https://news.ycombinator.com/newsguidelines.html.

I agree the snark was unnecessary, but in that moment I didn't have the time to think of a way to say that without it being perceived as worse than what I did playfully say.

Anyway, wrist slap accepted. I will do better in the future.

Edit: from that page, what's the meaning of the sentence "Edit out swipes."?

HN comments shouldn't contain swipes or putdowns, but of course those have a way of sneaking in to one's comments anyhow, so that guideline is asking people to re-read what they've posted and, if they notice a swipe, to edit it out.

Kind of a crossover thing from the blind cooking post, but it's interesting that they have smaller eyes and smaller brains.

Basically, if you assume that vision requires a lot of compute power to process, and that compute power (that is, brains) are major energy users, those with simpler vision processing needs use less energy.

It's kind of a first principles thing I suppose. What uses a lot of energy? Brain. What is the brain doing a lot? Managing vision. Idea? Reduce vision input.

how does this apply to octopuses having brain-like tissue ina ll it's arms?

They have that for the same reason, because they have huge arrays of sensors in their arms and they need to process their output close to the sensors, due to the low speed of propagation of signals through nerves.

An artificial robot does not have these constraints of proximity between sensors and the place where their output is processed, because the delay over electrical wires is negligible at the time scale of most sensor outputs.

A big factor is also the lack of predators. To help avoid predators, it helps to have good eyes and the brains to process what you see. If there are no predators, then other factors exert their influence. Large, complex organs consume lots of energy and "harmful" mutations that shrink them will accumulate because the lack of energy on prehistoric Mallorca makes that an advantage.

Wow - mind blown. I had somehow assumed large creatures can't be cold-blooded

It's a pygmy goat, it's smaller than a croc or a dragon.

Are dragons cold blooded? I thought most of them breathed fire.

Comodo dragon, I'm assuming

They're certainly cold blooded enough when it comes to paying them for ssl certs.

Imagine have a tiny, lazy goat for a pet.

I want a cashmere one to use as a pillow

Tiny is done, a Pygmy is about the same or you have a slightly larger Nigerian Dwarf of miniature.

Goats 'thing' is their energy. (they will still snuggle during post lunch nap time though)

It's hard to know why you'd want a lazy goat, what comes to mind is house training. That might work.

Also these goats (Myotragus balearicus) are not cold-blooded (Not sure where the headline came from) and I wouldn't call them a goat, since they are closer to a mountain goat which I don't call a goat because they are not a Capra.

"Myotragus balearicus" would be a good black metal band name now. The cold-blooded goat.

"good" LOL

(2009)

Added. Thanks!

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