7 ms·

What Happened to Ancient Megafauna?

86 points by jnord 2y ago

idunnoman1222 2y ago
This is not about assigning blame, says Svenning. “People who lived thousands of years ago never had access to the full picture. These things took place across long time scales and big spatial scales over which no one had an overview; whatever people did, it was difficult to see the consequences. Plus, of course, people just had to survive the best they could.” - lol even
linearrust 2y ago
> Defined as large-bodied terrestrial mammals with a mean adult body mass of 2,200 pounds or more, today’s remaining megaherbivores comprise the likes of elephants, rhinoceroses, giraffes, and hippopotamuses. Was there difference in hunter-gatherers in europe/asia/americas compared to africa? Why hadn't the ancient elephants, giraffes, etc been hunted to extinction? > I think work over the past few decades has rather convincingly demonstrated that humans had a pretty substantial part in the extinction A substantial part in the extinction? What does that mean? The extermination of the buffalo in the US required industrial scale resources ( guns, railroads, etc ) along with the migration of millions of europeans and habitat loss ( via farming ). It was a conscious and intentional effort. Are they claiming something similar happened throughout much of europe, asia and americas more than 50,000 year ago? > “When we restore forests, we can’t just think about the trees,” he says. “We must think about the animals that belong there.” This. The most devastating blow for the buffalo, wolves, bears, etc was habitat loss. It was ultimately what did them in. Did ancient hunter-gatherers alter their environment to such a degree to wipe out herds of giant animals from entire continents? I have a hard time believing that hunter gathers in tiny tribes traveling on foot with primitive weapons could have hunted and wiped out entire species of large animals from continents. I wish they would give more specifics.
- mr_toad 2y ago
  > Was there difference in hunter-gatherers in europe/asia/americas compared to africa? Why hadn't the ancient elephants, giraffes, etc been hunted to extinction? One theory is that they gradually adapted as humans developed. Once humans spread out to other continents the change was too rapid for the megafauna on those continents to adapt.
  - simonh 2y ago
    Also there were megafauna extinctions in Africa, just over a longer period of time. Then humans expand out of Africa, and within a few tens of thousands of years most of the extra-African megafauna are gone.
- nkrisc 2y ago
  > Was there difference in hunter-gatherers in europe/asia/americas compared to africa? Why hadn't the ancient elephants, giraffes, etc been hunted to extinction? Consider that African megafauna have co-existed with early hominids and eventually humans for millions of years. They may have simply adapted to human predation successfully enough to survive, as one factor. Whereas in North America and elsewhere you have the sudden (on the evolutionary time scale) arrival of Homo Sapiens who are likely already very skilled and advanced hunters among a population of prey animals that have never experienced such a predator. It’s also possible that in tandem, climate change was less severe in Africa than elsewhere over the last 50k years.
  - BurningFrog 2y ago
    Right, we're a native species to Africa, so its whole ecosystem evolved with us. I think of this when I hear about "poachers" killing animals in African nature reserves. How often is that hunter gatherers who been there for thousands of years, and whose hunting is/was really part of the ecosystem?
    - hanniabu 2y ago
      Comparing hunting with rudimentary weapons to hunting with modern firearms is insane
      - yCombLinks 2y ago
        Not to mention modern mobility
        hanniabu 2y ago
        Plus cameras and drones
        adolph 2y ago
        Wild hogs seem to handle it pretty well
- AlotOfReading 2y ago
  They don't know any particular specifics. Our understanding of human organization during the late pleistocene and early Holocene is poor, bordering on non-existent. However, I don't find it particularly hard to imagine humans as a major factor, even if I have some doubts about this particular argument. First, you have to understand that about the late quaternary extinctions, we know not all quaternary extinctions were anthropogenic. Ecosystems were experiencing a lot of different stressors around that time, and by the time extinction actually happens there may have been only small populations left for centuries or millennia. Ecological resilience is also a bit of a funny thing. You might think that you make 10 species extinct has 10x more impact than just 1 extinction, but there isn't a linear relationship. In many ecosystems, there's very little impact from most local extinctions as the graph thins out until all the systemic resilience is gone and the whole thing suddenly collapses into a new state. Did that proximate cause(s) of the last extinction cause the rapid shift? Fantastically deadly hunters like humans that are specialized to megafaunal hunting being able to push the most vulnerable and stressed parts of the ecosystem over the edge isn't an obviously absurd argument to me.
- alfiedotwtf 2y ago
  Thinking out loud… I wonder if it could still be true based on the fact that the larger the animal, the longer the gestation period. For small animals like rabbits, it’s about 30 days - so their chances of “multiplying like rabbits” is obvious - you’re not going to wipe out rabbits faster than the supply. As you move up the size scale, the gestation period gets longer and longer, and each kill gets harder to replace (wales come in at around 18 months!). Kill a mega-sloth and its chances of species survival dramatically drop!
  - shawn_w 2y ago
    The number of offspring in each litter tends to drop with increasing size, too.
- deadbolt 2y ago
  > The most devastating blow for the buffalo, wolves, bears, etc was habitat loss. Wasn't the most devastating blow to Buffalo the campaign by settlers to slaughter them, since they were important to the native Americans?
  - daemonologist 2y ago
    True for the American bison (as far as I know), but there used to be a bunch of species in Eurasia which went extinct or had their range dramatically reduced as part of the broader extinction of megafauna discussed in the article.
  - dghughes 2y ago
    I think the word buffalo really confuses people. Bison are in North America while buffalo (small b) are in Asia and Africa. >Wasn't the most devastating blow to Buffalo the campaign by settlers to slaughter them I hope everyone in the city of Buffalo, NY are OK lol
    - amanaplanacanal 2y ago
      Buffalo buffalo Buffalo buffalo buffalo buffalo Buffalo buffalo.
    - LeFantome 2y ago
      You are of course correct. In North America at least though, I do not believe many people are confused. The term “buffalo” is used much more commonly than “Prarie Bison”. I am not defending it but it is ubiquitous to the point that everybody knows what people mean when they say “buffalo”. If somebody said “buffalo” to me, I would assume they meant bison ( unless I had additional context ). If they meant Asian or African buffalo, I would expect them to say “water buffalo”. Again, I am not arguing what is correct. I am commenting on what I think people, as a group, understand.
- Earw0rm 2y ago
  Not all megafauna are herd animals on the scale of American buffalo. Others were limited to smaller areas or less numerous to begin with, and the ones that survive are probably those that started off most numerous. African elephants are hanging on by a thread, relative to their original number they're down something like 98%. Africa is also _huge_ - around four times the size of the entire continental USA - and suffered perhaps less during the Ice Ages than Northern America or Eurasia, where megafauna would have been squeezed by both the ice - and associated climate changes further south - and a hungry and increasingly innovative human population.
- TeMPOraL 2y ago
  > I have a hard time believing that hunter gathers in tiny tribes traveling on foot with primitive weapons could have hunted and wiped out entire species of large animals from continents One thing humans could was starting fires that would drive many animals into a designated killbox, among other ways of "cheating". Humans were uniquely capable (at this size scale, at least) to both hunt species in excess to their need and cause outsized damage to their habitat in the process.
  - kjkjadksj 2y ago
    The default is to outpace your need. Imagine if we evolved to somehow hunt just enough meat. There’d be some of us with less efficient systems for controlling that behavior that end up starving while they think they are bringing in enough food. Thats no good for reproductive fitness. Overshooting on the other hand is good. Another factor, symbiotic relationships tend take much longer to evolve that carefully balanced relationship between symbiont and symbiont. Parasitic relationships tend to evolve sooner and its also not uncommon the parasite overshoots and kills off its own host.
- trhway 2y ago
  >I have a hard time believing that hunter gathers in tiny tribes traveling on foot with primitive weapons could have hunted and wiped out entire species of large animals from continents last mammoth died just 4000 years ago on an Arctic island - i.e. without humans they survived far longer even in pretty harsh conditions.
- christkv 2y ago
  They are guessing. Probably a ton of compounding factors rather than a single one. Ice age (probably a big one for anything not in Africa), hunting, habitat compression, food competition, etc. I'm also guessing :)
- nihzm 2y ago
  > I have a hard time believing that hunter gathers in tiny tribes traveling on foot with primitive weapons could have hunted and wiped out entire species of large animals from continents. I wish they would give more specifics. This made me recall having read something related to it in the book Sapiens [1]. Indeed, I went looking and quoting from chapter 4 > All the settlers of Australia had at their disposal was Stone Age technology. How could they cause an ecological disaster? There are three explanations that mesh quite nicely. > Large animals – the primary victims of the Australian extinction – breed slowly. Pregnancy is long, offspring per pregnancy are few, and there are long breaks between pregnancies. Consequently, if humans cut down even one diprotodon every few months, it would be enough to cause diprotodon deaths to outnumber births. Within a few thousand years the last, lonesome diprotodon would pass away, and with her the entire species. [...] > The second explanation is that by the time Sapiens reached Australia, they had already mastered fire agriculture. Faced with an alien and threatening environment, they deliberately burned vast areas of impassable thickets and dense forests to create open grasslands, which attracted more easily hunted game, and were better suited to their needs. They thereby completely changed the ecology of large parts of Australia within a few short millennia. [...] > A third explanation agrees that hunting and fire agriculture played a significant role in the extinction, but emphasises that we can’t completely ignore the role of climate. The climate changes that beset Australia about 45,000 years ago destabilised the ecosystem and made it particularly vulnerable. [...] So the extinction was on a very different timescale from your buffalo example, but an extintion nonetheless. In the ellipses the book briefly points to some evidence to support these theories. [1]: https://en.wikipedia.org/wiki/Sapiens:_A_Brief_History_of_Humankind https://en.wikipedia.org/wiki/Sapiens:_A_Brief_History_of_Hu...
- graemep 2y ago
  > Was there difference in hunter-gatherers in europe/asia/americas compared to africa? Why hadn't the ancient elephants, giraffes, etc been hunted to extinction? Elephants and rhinos do survive in Asia.
throwup238 2y ago
I'm still digesting the full paper [1] but it looks like the gist is that when you put all the previously published data together, the timing of megafauna extinction statistically lines up with human arrival better than climate change. The most important pieces of evidence they seem to look at is fungal spores in fossilized poop and sedimentary ancient DNA: > Further, other studies show contrasting patterns. For example, a sedimentary ancient DNA (sedaDNA) study from the Yukon shows strong megafauna decline between 21 and 14,500 years ago, prior to the loss of the mammoth steppe biome and the Younger Dryas. In addition, as already mentioned, many extinct megafauna species have last occurrences in the Early or even Middle Holocene, that is, during the relatively stable climate of the Holocene, meaning that a climatic cause for their extinction is unlikely given their previous survival through numerous, massive climatic shifts throughout the Pleistocene, including long and warm interglacial periods. > An increasing number of studies look at local and regional dynamics in the overall abundance of large herbivores at high spatiotemporal resolution using dung-associated fungal spores. Many of these are able to pinpoint declines to timeframes where the climate was stable, for example, North America ~14–13,000 years ago, prior to the Younger Dryas cooling, and 41,000 years ago in Australia at a time of no substantial climate change These techniques are still very new and they're so sensitive that they should be taken with a grain of salt, sedaDNA especially since it amplifies tiny snippets of DNA found in permafrost. We assume permafrost behaves like an annually laminated sediment but that's controversial and archaeology/paleontology have had plenty of problems before with DNA snippets and contamination. [1] https://www.cambridge.org/core/journals/cambridge-prisms-extinction/article/latequaternary-megafauna-extinctions-patterns-causes-ecological-consequences-and-implications-for-ecosystem-management-in-the-anthropocene/E885D8C5C90424254C1C75A61DE9D087 https://www.cambridge.org/core/journals/cambridge-prisms-ext...
cryptonector 2y ago
This guy (https://www.youtube.com/@Antonio_Zamora https://www.youtube.com/@Antonio_Zamora) makes a very solid argument that in the Younger Dryas a meteorite impactor hit the ice sheet over the Great Lakes, sending huge ice chunks flying that created elliptical craters that then quickly refilled that are called the Carolina Bays, and which are ubiquitous in the South East, and which point back at the impact point(s) (I think he says there were two impact points) in Michigan. The amount of energy delivered by all those ice chunks seems to have been several megatons (of TNT) per square mile. Enough chunks were ejected, and carolina bays formed, to have likely caused an extinction event.
- AlotOfReading 2y ago
  There's a real danger in getting misinformation from YouTube channels. The Younger Dryas Impact Hypothesis has been extensively refuted multiple times. The latest such paper (https://doi.org/10.1016/j.earscirev.2023.104502 https://doi.org/10.1016/j.earscirev.2023.104502) is pretty exhaustive in exploring the history of these ideas and how they fall short.
  - alfiedotwtf 2y ago
    YouTube is like the anti-Wikipedia. It’s easy to create videos and the only check are comments buried 200 comments down
  - hnfong 2y ago
    In your link, the first words of the abstract is: "A series of publications purport to provide evidence that..." So even published papers contain such "misinformation", it isn't specific to Youtube. I have no training in the areas of archaeological evidence, so I don't know what to make of the paper, but it looks like people are just arguing about evidence of whether there was an asteroid impact. It's interesting though that the title of the paper is called "Complete Refutation" of the hypothesis and not of the evidence. If you're nit-picky enough you'd notice that the YDIH isn't a "scientific" hypothesis per se since hypotheses about what happened in the past doesn't really give testable predictions, and actually what they did in the paper was to refute all the evidence of the hypothesis -- but it seems to me it's still theoretically possible for new evidence to come up that definitely supports YDIH. Also, AFAICT this only rules out the asteroid impact. It still doesn't rule out the possibility that the abrupt climate changes during the Younger Dryas causing stress to the megafauna population, which presumably is another thing.
1529454o3 2y ago
[flagged]
defrost 2y ago
The linked nautil.us article is a one sided poor summary of what is still an ongoing debate with strong beliefs on either side. Two people are quoted: * Jens-Christian Svenning, director of the Danish National Research Foundation’s Center for Ecological Dynamics in a Novel Biosphere at Aarhus University. He’s also the lead author on a recent paper published in Cambridge Prisms: Extinction that argues it was not climate change but rather human hunting that caused the extinction of most megaherbivores over the past 50,000 years. and * Felisa Smith, a conservation paleoecologist and professor at the University of New Mexico, believes that the human impact on megafauna extinction is no longer up for debate. “I think work over the past few decades has rather convincingly demonstrated that humans had a pretty substantial part in the extinction,” says Smith. and ... no other views are given. This, currently, isn't a slam dunk for one side, there are strong voices on the other side who can cite examples where humans certainly ate megafauna but not, apparently, enough to wipe them out and also point at concurrent pockets (eg: Tasmania) where there were megafauna, as yet no humans, and still the megafauna died out.
- Xen9 2y ago
  Darwin (1) near consistently included each and every argument & counter-argument to the point where it becomes boring and unreasonable to go any further (2) was absolutely explicit of what was NOT included to the point that there were redunant remarks about that! --- The view of Smith is laughable, for the human population has changed by more than few orders of magnitude since those times. Yet it would be plausible that a global MF ecosystem was distrupted somehow. Another possible reason megafauna died: they eat plants and grew on top of an ecosystem where there was not much competition for plants, and then an increase in efficiency of bacteria, bugs, invertebrates and other compact herbivore species in consumption of the limited amount of plant food pulled the legs under them. Whales were not herbivores, and possibly therefore not subject to same mechanisms (though saying this sort of ruins the metaphor of pulling legs from underneath).
- arthurbrown 2y ago
  Could you provide some more details about the Tasmania example? Seems humans reached Tas "at least" ~40,000 years ago from my simple searching, which isnt too far off from the generalised 50,000 mentioned in the article. Which species went extinct before then? https://www.sciencedirect.com/science/article/pii/S0305440323000997 https://www.sciencedirect.com/science/article/pii/S030544032...
kleiba 2y ago
One idea I had a while back is this: with all our modern technology in stem cell research, gene modification and cloning, shouldn't it be possible to recreate actual living clones from prehistoric dinosaur DNA? I mean, sure, these giant wild animals could potentially become dangerous, but how about we confine them to a remote island or so?!
- alserio 2y ago
  Good idea, like a park of something? The most difficult part would be naming it. You could go for something like Cretaceus Park, but it doesn't sound too good.
  - knifie_spoonie 2y ago
    Billy's Cloneasaurus Park
    - kleiba 2y ago
      Nailed it!
  - kleiba 2y ago
    Oh, a park! Like, where people come and can look at the creatures for an entrance fee? Yeah, sure why not. Also like your naming idea, perhaps something a little catchier?
    - alserio 2y ago
      Imagine a new generation of kids that likes dinosaurs and can actually see them roaming. Can't wait to see the look on their faces when I tell them that I was into dinosaurs when they were still underground
- ainiriand 2y ago
  I believe that you will only need one IT person and I would like the job!
chucke1992 2y ago
It died.
Keysh 2y ago
The (Nautilus) article is confusing in the way it conflates "megaherbivores" (herbivores weighing more than 1 [metric] ton) and "megafauna" (any animal, regardless of what it eats, weighing more than 45 kg[1]). Also: "Giant ground sloths, musk oxen, and short-faced kangaroos: All have gone the way of the dodo" -- A) Of those three animals, only the giant ground sloth was big enough to qualify as a megaherbivore; and B) musk oxen are very much not extinct! [1] Which I assume is a translation of an older definition using 100 lb as the lower limit.
fuzzfactor 2y ago
I always figured they were delicious.
- imp0cat 2y ago
  They probably weren't THAT delicious, but the portions were huge! ;)
rfwhyte 2y ago
It's always seemed patently obvious to me that humans were the primary cause of megafauna extinctions. First and foremost because the timing of extinctions aligns so closely with the arrival of humans in a given region, but also because the climate has changed dramatically over the past few million years or so, with cooler or warmer periods happening frequently over geological timespans, yet we don't see similar extinction events happening around climatic cycles / events other than those that happen to align with the arrival of humans in a given region. The Mammoths of North America for example survived numerous cycles of warming and cooling, some far more drastic than the most recent ice age and subsequent warming period, so why was it only the most recent one that caused their extinction? We already have control data for the effect climate had on megafauna populations, the only variable left is us humans.
mofoteam 2y ago
[dead]

86 points by jnord 2y ago

This is not about assigning blame, says Svenning. “People who lived thousands of years ago never had access to the full picture. These things took place across long time scales and big spatial scales over which no one had an overview; whatever people did, it was difficult to see the consequences. Plus, of course, people just had to survive the best they could.” - lol even

linearrust 2y ago

> Defined as large-bodied terrestrial mammals with a mean adult body mass of 2,200 pounds or more, today’s remaining megaherbivores comprise the likes of elephants, rhinoceroses, giraffes, and hippopotamuses. Was there difference in hunter-gatherers in europe/asia/americas compared to africa? Why hadn't the ancient elephants, giraffes, etc been hunted to extinction? > I think work over the past few decades has rather convincingly demonstrated that humans had a pretty substantial part in the extinction A substantial part in the extinction? What does that mean? The extermination of the buffalo in the US required industrial scale resources ( guns, railroads, etc ) along with the migration of millions of europeans and habitat loss ( via farming ). It was a conscious and intentional effort. Are they claiming something similar happened throughout much of europe, asia and americas more than 50,000 year ago? > “When we restore forests, we can’t just think about the trees,” he says. “We must think about the animals that belong there.” This. The most devastating blow for the buffalo, wolves, bears, etc was habitat loss. It was ultimately what did them in. Did ancient hunter-gatherers alter their environment to such a degree to wipe out herds of giant animals from entire continents? I have a hard time believing that hunter gathers in tiny tribes traveling on foot with primitive weapons could have hunted and wiped out entire species of large animals from continents. I wish they would give more specifics.

mr_toad 2y ago
> Was there difference in hunter-gatherers in europe/asia/americas compared to africa? Why hadn't the ancient elephants, giraffes, etc been hunted to extinction? One theory is that they gradually adapted as humans developed. Once humans spread out to other continents the change was too rapid for the megafauna on those continents to adapt.
- simonh 2y ago
  Also there were megafauna extinctions in Africa, just over a longer period of time. Then humans expand out of Africa, and within a few tens of thousands of years most of the extra-African megafauna are gone.
nkrisc 2y ago
> Was there difference in hunter-gatherers in europe/asia/americas compared to africa? Why hadn't the ancient elephants, giraffes, etc been hunted to extinction? Consider that African megafauna have co-existed with early hominids and eventually humans for millions of years. They may have simply adapted to human predation successfully enough to survive, as one factor. Whereas in North America and elsewhere you have the sudden (on the evolutionary time scale) arrival of Homo Sapiens who are likely already very skilled and advanced hunters among a population of prey animals that have never experienced such a predator. It’s also possible that in tandem, climate change was less severe in Africa than elsewhere over the last 50k years.
- BurningFrog 2y ago
  Right, we're a native species to Africa, so its whole ecosystem evolved with us. I think of this when I hear about "poachers" killing animals in African nature reserves. How often is that hunter gatherers who been there for thousands of years, and whose hunting is/was really part of the ecosystem?
  - hanniabu 2y ago
    Comparing hunting with rudimentary weapons to hunting with modern firearms is insane
    - yCombLinks 2y ago
      Not to mention modern mobility
      - hanniabu 2y ago
        Plus cameras and drones
        adolph 2y ago
        Wild hogs seem to handle it pretty well
AlotOfReading 2y ago
They don't know any particular specifics. Our understanding of human organization during the late pleistocene and early Holocene is poor, bordering on non-existent. However, I don't find it particularly hard to imagine humans as a major factor, even if I have some doubts about this particular argument. First, you have to understand that about the late quaternary extinctions, we know not all quaternary extinctions were anthropogenic. Ecosystems were experiencing a lot of different stressors around that time, and by the time extinction actually happens there may have been only small populations left for centuries or millennia. Ecological resilience is also a bit of a funny thing. You might think that you make 10 species extinct has 10x more impact than just 1 extinction, but there isn't a linear relationship. In many ecosystems, there's very little impact from most local extinctions as the graph thins out until all the systemic resilience is gone and the whole thing suddenly collapses into a new state. Did that proximate cause(s) of the last extinction cause the rapid shift? Fantastically deadly hunters like humans that are specialized to megafaunal hunting being able to push the most vulnerable and stressed parts of the ecosystem over the edge isn't an obviously absurd argument to me.
alfiedotwtf 2y ago
Thinking out loud… I wonder if it could still be true based on the fact that the larger the animal, the longer the gestation period. For small animals like rabbits, it’s about 30 days - so their chances of “multiplying like rabbits” is obvious - you’re not going to wipe out rabbits faster than the supply. As you move up the size scale, the gestation period gets longer and longer, and each kill gets harder to replace (wales come in at around 18 months!). Kill a mega-sloth and its chances of species survival dramatically drop!
- shawn_w 2y ago
  The number of offspring in each litter tends to drop with increasing size, too.
deadbolt 2y ago
> The most devastating blow for the buffalo, wolves, bears, etc was habitat loss. Wasn't the most devastating blow to Buffalo the campaign by settlers to slaughter them, since they were important to the native Americans?
- daemonologist 2y ago
  True for the American bison (as far as I know), but there used to be a bunch of species in Eurasia which went extinct or had their range dramatically reduced as part of the broader extinction of megafauna discussed in the article.
- dghughes 2y ago
  I think the word buffalo really confuses people. Bison are in North America while buffalo (small b) are in Asia and Africa. >Wasn't the most devastating blow to Buffalo the campaign by settlers to slaughter them I hope everyone in the city of Buffalo, NY are OK lol
  - amanaplanacanal 2y ago
    Buffalo buffalo Buffalo buffalo buffalo buffalo Buffalo buffalo.
  - LeFantome 2y ago
    You are of course correct. In North America at least though, I do not believe many people are confused. The term “buffalo” is used much more commonly than “Prarie Bison”. I am not defending it but it is ubiquitous to the point that everybody knows what people mean when they say “buffalo”. If somebody said “buffalo” to me, I would assume they meant bison ( unless I had additional context ). If they meant Asian or African buffalo, I would expect them to say “water buffalo”. Again, I am not arguing what is correct. I am commenting on what I think people, as a group, understand.
Earw0rm 2y ago
Not all megafauna are herd animals on the scale of American buffalo. Others were limited to smaller areas or less numerous to begin with, and the ones that survive are probably those that started off most numerous. African elephants are hanging on by a thread, relative to their original number they're down something like 98%. Africa is also _huge_ - around four times the size of the entire continental USA - and suffered perhaps less during the Ice Ages than Northern America or Eurasia, where megafauna would have been squeezed by both the ice - and associated climate changes further south - and a hungry and increasingly innovative human population.
TeMPOraL 2y ago
> I have a hard time believing that hunter gathers in tiny tribes traveling on foot with primitive weapons could have hunted and wiped out entire species of large animals from continents One thing humans could was starting fires that would drive many animals into a designated killbox, among other ways of "cheating". Humans were uniquely capable (at this size scale, at least) to both hunt species in excess to their need and cause outsized damage to their habitat in the process.
- kjkjadksj 2y ago
  The default is to outpace your need. Imagine if we evolved to somehow hunt just enough meat. There’d be some of us with less efficient systems for controlling that behavior that end up starving while they think they are bringing in enough food. Thats no good for reproductive fitness. Overshooting on the other hand is good. Another factor, symbiotic relationships tend take much longer to evolve that carefully balanced relationship between symbiont and symbiont. Parasitic relationships tend to evolve sooner and its also not uncommon the parasite overshoots and kills off its own host.
trhway 2y ago
>I have a hard time believing that hunter gathers in tiny tribes traveling on foot with primitive weapons could have hunted and wiped out entire species of large animals from continents last mammoth died just 4000 years ago on an Arctic island - i.e. without humans they survived far longer even in pretty harsh conditions.
christkv 2y ago
They are guessing. Probably a ton of compounding factors rather than a single one. Ice age (probably a big one for anything not in Africa), hunting, habitat compression, food competition, etc. I'm also guessing :)
nihzm 2y ago
> I have a hard time believing that hunter gathers in tiny tribes traveling on foot with primitive weapons could have hunted and wiped out entire species of large animals from continents. I wish they would give more specifics. This made me recall having read something related to it in the book Sapiens [1]. Indeed, I went looking and quoting from chapter 4 > All the settlers of Australia had at their disposal was Stone Age technology. How could they cause an ecological disaster? There are three explanations that mesh quite nicely. > Large animals – the primary victims of the Australian extinction – breed slowly. Pregnancy is long, offspring per pregnancy are few, and there are long breaks between pregnancies. Consequently, if humans cut down even one diprotodon every few months, it would be enough to cause diprotodon deaths to outnumber births. Within a few thousand years the last, lonesome diprotodon would pass away, and with her the entire species. [...] > The second explanation is that by the time Sapiens reached Australia, they had already mastered fire agriculture. Faced with an alien and threatening environment, they deliberately burned vast areas of impassable thickets and dense forests to create open grasslands, which attracted more easily hunted game, and were better suited to their needs. They thereby completely changed the ecology of large parts of Australia within a few short millennia. [...] > A third explanation agrees that hunting and fire agriculture played a significant role in the extinction, but emphasises that we can’t completely ignore the role of climate. The climate changes that beset Australia about 45,000 years ago destabilised the ecosystem and made it particularly vulnerable. [...] So the extinction was on a very different timescale from your buffalo example, but an extintion nonetheless. In the ellipses the book briefly points to some evidence to support these theories. [1]: https://en.wikipedia.org/wiki/Sapiens:_A_Brief_History_of_Humankind https://en.wikipedia.org/wiki/Sapiens:_A_Brief_History_of_Hu...
graemep 2y ago
> Was there difference in hunter-gatherers in europe/asia/americas compared to africa? Why hadn't the ancient elephants, giraffes, etc been hunted to extinction? Elephants and rhinos do survive in Asia.

throwup238 2y ago

I'm still digesting the full paper [1] but it looks like the gist is that when you put all the previously published data together, the timing of megafauna extinction statistically lines up with human arrival better than climate change. The most important pieces of evidence they seem to look at is fungal spores in fossilized poop and sedimentary ancient DNA: > Further, other studies show contrasting patterns. For example, a sedimentary ancient DNA (sedaDNA) study from the Yukon shows strong megafauna decline between 21 and 14,500 years ago, prior to the loss of the mammoth steppe biome and the Younger Dryas. In addition, as already mentioned, many extinct megafauna species have last occurrences in the Early or even Middle Holocene, that is, during the relatively stable climate of the Holocene, meaning that a climatic cause for their extinction is unlikely given their previous survival through numerous, massive climatic shifts throughout the Pleistocene, including long and warm interglacial periods. > An increasing number of studies look at local and regional dynamics in the overall abundance of large herbivores at high spatiotemporal resolution using dung-associated fungal spores. Many of these are able to pinpoint declines to timeframes where the climate was stable, for example, North America ~14–13,000 years ago, prior to the Younger Dryas cooling, and 41,000 years ago in Australia at a time of no substantial climate change These techniques are still very new and they're so sensitive that they should be taken with a grain of salt, sedaDNA especially since it amplifies tiny snippets of DNA found in permafrost. We assume permafrost behaves like an annually laminated sediment but that's controversial and archaeology/paleontology have had plenty of problems before with DNA snippets and contamination. [1] https://www.cambridge.org/core/journals/cambridge-prisms-extinction/article/latequaternary-megafauna-extinctions-patterns-causes-ecological-consequences-and-implications-for-ecosystem-management-in-the-anthropocene/E885D8C5C90424254C1C75A61DE9D087 https://www.cambridge.org/core/journals/cambridge-prisms-ext...

cryptonector 2y ago

This guy (https://www.youtube.com/@Antonio_Zamora https://www.youtube.com/@Antonio_Zamora) makes a very solid argument that in the Younger Dryas a meteorite impactor hit the ice sheet over the Great Lakes, sending huge ice chunks flying that created elliptical craters that then quickly refilled that are called the Carolina Bays, and which are ubiquitous in the South East, and which point back at the impact point(s) (I think he says there were two impact points) in Michigan. The amount of energy delivered by all those ice chunks seems to have been several megatons (of TNT) per square mile. Enough chunks were ejected, and carolina bays formed, to have likely caused an extinction event.

AlotOfReading 2y ago
There's a real danger in getting misinformation from YouTube channels. The Younger Dryas Impact Hypothesis has been extensively refuted multiple times. The latest such paper (https://doi.org/10.1016/j.earscirev.2023.104502 https://doi.org/10.1016/j.earscirev.2023.104502) is pretty exhaustive in exploring the history of these ideas and how they fall short.
- alfiedotwtf 2y ago
  YouTube is like the anti-Wikipedia. It’s easy to create videos and the only check are comments buried 200 comments down
- hnfong 2y ago
  In your link, the first words of the abstract is: "A series of publications purport to provide evidence that..." So even published papers contain such "misinformation", it isn't specific to Youtube. I have no training in the areas of archaeological evidence, so I don't know what to make of the paper, but it looks like people are just arguing about evidence of whether there was an asteroid impact. It's interesting though that the title of the paper is called "Complete Refutation" of the hypothesis and not of the evidence. If you're nit-picky enough you'd notice that the YDIH isn't a "scientific" hypothesis per se since hypotheses about what happened in the past doesn't really give testable predictions, and actually what they did in the paper was to refute all the evidence of the hypothesis -- but it seems to me it's still theoretically possible for new evidence to come up that definitely supports YDIH. Also, AFAICT this only rules out the asteroid impact. It still doesn't rule out the possibility that the abrupt climate changes during the Younger Dryas causing stress to the megafauna population, which presumably is another thing.

1529454o3 2y ago

[flagged]

defrost 2y ago

The linked nautil.us article is a one sided poor summary of what is still an ongoing debate with strong beliefs on either side. Two people are quoted: * Jens-Christian Svenning, director of the Danish National Research Foundation’s Center for Ecological Dynamics in a Novel Biosphere at Aarhus University. He’s also the lead author on a recent paper published in Cambridge Prisms: Extinction that argues it was not climate change but rather human hunting that caused the extinction of most megaherbivores over the past 50,000 years. and * Felisa Smith, a conservation paleoecologist and professor at the University of New Mexico, believes that the human impact on megafauna extinction is no longer up for debate. “I think work over the past few decades has rather convincingly demonstrated that humans had a pretty substantial part in the extinction,” says Smith. and ... no other views are given. This, currently, isn't a slam dunk for one side, there are strong voices on the other side who can cite examples where humans certainly ate megafauna but not, apparently, enough to wipe them out and also point at concurrent pockets (eg: Tasmania) where there were megafauna, as yet no humans, and still the megafauna died out.

Xen9 2y ago
Darwin (1) near consistently included each and every argument & counter-argument to the point where it becomes boring and unreasonable to go any further (2) was absolutely explicit of what was NOT included to the point that there were redunant remarks about that! --- The view of Smith is laughable, for the human population has changed by more than few orders of magnitude since those times. Yet it would be plausible that a global MF ecosystem was distrupted somehow. Another possible reason megafauna died: they eat plants and grew on top of an ecosystem where there was not much competition for plants, and then an increase in efficiency of bacteria, bugs, invertebrates and other compact herbivore species in consumption of the limited amount of plant food pulled the legs under them. Whales were not herbivores, and possibly therefore not subject to same mechanisms (though saying this sort of ruins the metaphor of pulling legs from underneath).
arthurbrown 2y ago
Could you provide some more details about the Tasmania example? Seems humans reached Tas "at least" ~40,000 years ago from my simple searching, which isnt too far off from the generalised 50,000 mentioned in the article. Which species went extinct before then? https://www.sciencedirect.com/science/article/pii/S0305440323000997 https://www.sciencedirect.com/science/article/pii/S030544032...

kleiba 2y ago

One idea I had a while back is this: with all our modern technology in stem cell research, gene modification and cloning, shouldn't it be possible to recreate actual living clones from prehistoric dinosaur DNA? I mean, sure, these giant wild animals could potentially become dangerous, but how about we confine them to a remote island or so?!

alserio 2y ago
Good idea, like a park of something? The most difficult part would be naming it. You could go for something like Cretaceus Park, but it doesn't sound too good.
- knifie_spoonie 2y ago
  Billy's Cloneasaurus Park
  - kleiba 2y ago
    Nailed it!
- kleiba 2y ago
  Oh, a park! Like, where people come and can look at the creatures for an entrance fee? Yeah, sure why not. Also like your naming idea, perhaps something a little catchier?
  - alserio 2y ago
    Imagine a new generation of kids that likes dinosaurs and can actually see them roaming. Can't wait to see the look on their faces when I tell them that I was into dinosaurs when they were still underground
ainiriand 2y ago
I believe that you will only need one IT person and I would like the job!

chucke1992 2y ago

It died.

Keysh 2y ago

The (Nautilus) article is confusing in the way it conflates "megaherbivores" (herbivores weighing more than 1 [metric] ton) and "megafauna" (any animal, regardless of what it eats, weighing more than 45 kg[1]). Also: "Giant ground sloths, musk oxen, and short-faced kangaroos: All have gone the way of the dodo" -- A) Of those three animals, only the giant ground sloth was big enough to qualify as a megaherbivore; and B) musk oxen are very much not extinct! [1] Which I assume is a translation of an older definition using 100 lb as the lower limit.

fuzzfactor 2y ago

I always figured they were delicious.

imp0cat 2y ago
They probably weren't THAT delicious, but the portions were huge! ;)

rfwhyte 2y ago

It's always seemed patently obvious to me that humans were the primary cause of megafauna extinctions. First and foremost because the timing of extinctions aligns so closely with the arrival of humans in a given region, but also because the climate has changed dramatically over the past few million years or so, with cooler or warmer periods happening frequently over geological timespans, yet we don't see similar extinction events happening around climatic cycles / events other than those that happen to align with the arrival of humans in a given region. The Mammoths of North America for example survived numerous cycles of warming and cooling, some far more drastic than the most recent ice age and subsequent warming period, so why was it only the most recent one that caused their extinction? We already have control data for the effect climate had on megafauna populations, the only variable left is us humans.

mofoteam 2y ago

[dead]