Welcome to r/science! This is a heavily moderated subreddit in order to keep the discussion on science. However, we recognize that many people want to discuss how they feel the research relates to their own personal lives, so to give people a space to do that, **personal anecdotes are allowed as responses to this comment**. Any anecdotal comments elsewhere in the discussion will be removed and our [normal comment rules]( https://www.reddit.com/r/science/wiki/rules#wiki_comment_rules) apply to all other comments.
**Do you have an academic degree?** We can verify your credentials in order to assign user flair indicating your area of expertise. [Click here to apply](https://reddit.science/flair?location=sticky).
---
User: u/mvea
Permalink: https://www.theguardian.com/science/article/2024/jun/27/last-woolly-mammoths-arctic-island
---
*I am a bot, and this action was performed automatically. Please [contact the moderators of this subreddit](/message/compose/?to=/r/science) if you have any questions or concerns.*
for a second I thought you were saying that it was your personal belief that 12 cheetahs started the species, rather than saying that you recalled that fact from somewhere, and I thought to myself “what an odd thing to share”
Imagine if the Wrangell Island Woolly mammoths survived the extinction event. You would probably have a headline like this:
"The Wrangell Island Woolly mammoths were discovered in 1820's by joint European-American arctic expedition team. They became rare by 1860's as new settlers to the Island began hunting them for meat, fur, and ivory. By 1890 the last mammoth was shot by a drunk prospecter who decided it would be fun to shoot something after a night of drinking whiskey and gambling with the boys. Here is picture of Gergory Horton holding his Winchester Rifle and standing proudly atop the dead mammoth, which was a pregnant female. The mother and her fetus were later shipped to the London Museum of Natural History and put on display."
The Dutch used them as an easy source of food, and the introduced rats ate the eggs. Your right though, there wasn't really much hunting needed though. Islands species living on remote islands don't have fear of humans. Dodos had no natural predators prior to humans.
The Falkland Island wolf for another example swam up to the first human colonists greeting them with wagging tail. They did not run from humans and so were easy to kill. Humans clubbed many of them to death.
Yeah, spay, neuter, and keep your kitties inside. They're still vicious little murderers, but at least indoors they're only murdering the animals that don't have the sense not to go into the murder house.
Yeah coyotes got a couple of my in-laws' cats. :( And even in areas without coyotes, outdoor cats have a significantly shortened life expectancy due to cars, parasites, and bigger, meaner cats.
In the United States, over 1 million vertebrate animals are killed by vehicle collisions every day. Globally, the number amounts to roughly 5.5 million killed per day, which when extrapolated climbs to over 2 billion annually.
My cat does nothing compared humans
Why do you think this is relevant? Cars do damage. Cats do damage. That’s like saying if I only shot and killed one person, it’s nothing because Stephen Paddock.
Because I have never seen people bitching about cars, but anytime a cat is mentioned someone is always saying keep your cats indoors. I am saying stop driving cars if you actually care about the environment.
False equivalence. People need to drive cars to live. Your cat doesn't need to be let outside to live.
This is like people complaining about the CO2 emissions of concrete in nuclear power plant construction as a reason not to build them. It's a completely misleading argument meant to draw attention away from the actual problem of fossil fuel consumption.
I was also thinking about the Thylacine (Tasmanian Tiger). It got shot, poisoned, and trapped into extinction by ranchers. Even though the animal did not kill livestock.
Yep. And the last known living one died of Hypothermia because the zoo keeper forgot to let it into its night enclosure. Poor thing. The photos of it haunt me.
Me too. Some people who've hiked the remote regions in Tasmania claim that they still exist but refuse to tell anyone where they saw them. It gives me hope. Let them rebuild in privacy as long as possible before we rediscover them and start breeding programs and set up protective fences and the like.
As a Tasmanian; no... no chance sorry.
The first and biggest issue is that Tasmanian tigers were Midland creatures. The midlands is now completely given over to pasture. That's also why all Tasmanian emus are gone. The landscape they had adapted for was entirely erased, and enclosures removed their ability to move to and from any scattered foliage that our idiot ancestors had failed to eradicate in their vendetta against all things living. The midlands is now basically a desert for most of its breadth.
The mountainous rainforest plateau is undeveloped... But is a completely different biome to the bushland that the tigers lived in. It's high altitude, extremely cold, extremely wet, with totally different animals and ecosystems
It's basically like taking an ostrich out of savannah and putting it in an alpine skiing retreat. It isn't going to survive. They can't cross those mountains, and even if they could, the weather conditions on the other side of the range are too extreme for them. That's why that side of the island is almost unpopulated; it's too extreme for anything except for absolute niche creatures to live in. It was used as the site for the most remote prison colony because it was (nearly, with a few high profile exceptions in the brief nice times of year) guaranteed to kill anyone who left shelter. Sadly, that applies to the animals too. You have to be specialised to survive year round.
Furthermore, having grown up in those temperate rainforest regions, there is absolutely no way you could maintain a secret location away from the population centres. There aren't the necessary roads and infrastructure; the tracks are all well known and widely used with no detours or opportunities for 'secret' routes anywhere. Every single one is known and used often by hunters, forestry workers, campers and hikers. Tasmania isn't that big, especially next to mai land Australia; there isn't a large space for things to hide in.
I've been camping with friends and we heard sounds, absolutely. But it was just plain hope; there are countless groups, people and bodies who desperately hope the Tiger is still out there somewhere and would do anything in their power to bring them back... But it isn't out there. It's gone.
From what I remember they're the animal we are most likely able to clone out of extinction, something to do with having the most intact DNA sequences out of all the extinct animals we could possibly clone.
It'll be tricky; none of our cloning techniques have been developed for marsupials, and there's some very key differences between marsupials and placental mammals. That's one of the reasons the thylacine cloning program is getting so much support, because even if it fails (and lots of experts expect it to fail) the techniques that need to be developed for it should be useful to save currently endangered marsupials.
I believe there's a couple of animals from the family that Ostriches, Emus, Kiwis and Cassowaries belong to that we also have pretty much entire DNA sequences for.
So those two are also on the cards.
Yep, they were basically hunted to extinction in the mid 1800's for their feathers, meat, and oil.
The Galapagos Giant Tortoise was also hunted to extinction due to the fact that it was, apparently, delicious. Of the 12 surviving subspecies (of the original 14 or 15), several are currently endangered.
No way they would have survived 70 years after discovery. Europeans killed off the estimated 2000 Stellar's sea cows only 27 years after discovering them.
To be fair, they were pretty much on the way out anyway.
Turns our raising sea levels had cut them off from their typical range and they were already dwindling.
Humans were just the final nail in the coffin.
Do you see manatees everywhere there's water?
Sea Cows were in the same family. They had preferred ranges, and also they were herbivores so the plants they eat grow in particular conditions.
In a
And do we see manatees preferred ranges shrinking as sea levels rise? Obviously a species isn’t going to use the entire ocean, I’m asking why the ocean being bigger would cause them to want less space.
Think of it this way.
Say your a group of people living in an archipelago where the islands are "connected" by relatively shallow seas where plenty of fish gather, in addition to other marine life (seaweeds, moluscs, and shorebirds).
The people living there don't have boats or the ability to make them, they're manner of moving from island to island is literally swimming through the shallow seas, and some of the islands are far enough away that this is time consuming and somewhat dangerous.
If the sea level rose 20 feet, then the distance gets farther. Also while they still have access to shallows where they can Harvest food, if they deplete an area it is now more difficult (or potentially not possible) to move between islands.
This is basically the situation that Sea Cows were in. Stuck in an area they couldn't leave where they would be especially susceptible to any changes in their local food supply.
For more information, look at Wikipedia. They have a section called "Dead Clade Walking" and "Extinction Debt" that goes into better detail.
“The mammoth’s tusks were mounted on a tree ring from the largest and oldest known Redwood he chopped down on a prospecting trip to California in an old growth forest. The rest of the tree was used to build a cabin for loggers.”
It would be difficult for a large and isolated population of megafauna to survive humans in the age of gun powder. Even now, remaining large animals are being killed in huge numbers for profit, due to habitat loss, and by the agricultural cartels.
For example, lions used to be native to Europe. Not even talking about the ice age. I'm talking more recently, like the bronze age. Greek scholars like Herodotus wrote about lions in Greece. There are even ancient Greek artworks depicting chariot riders hunting lions.
I'm guessing since they only analysed the remains of 13 specimens that it's based on genetic variance of each sample and charting then against time. Kinda like when people do a DNA test and they tell you how much of your DNA matches your dad/mom/sister/cousin
[https://en.wikipedia.org/wiki/Younger\_Dryas\_impact\_hypothesis](https://en.wikipedia.org/wiki/Younger_Dryas_impact_hypothesis)
This theory has really caught my eye mostly because there are a whole bunch of things that all happened pretty much at the same time. Goblekii Tempe was also in this time frame. There is still some healthy debate about it, but I lean towards this side as we learn more.
They have different samples dates from different eras and compared the observed heterozygosity of the earlier samples to the more recent samples. Then they simulated 108 models with varying severity of bottlenecks and recoveries and found the best fitting models to be those with a bottleneck of 8 Ne (effective population size) individuals. Only a bottleneck of that severity resulted in the closest fit for loss in observed heterozygosity.
I’ve linked to the news release in the post above. In this comment, for those interested, here’s the link to the peer reviewed journal article:
https://cell.com/cell/fulltext/S0092-8674(24)00577-4
From the linked article:
The last woolly mammoths on Earth took their final stand on a remote Arctic island about 4,000 years ago, but the question of what sealed their fate has remained a mystery. Now a genetic analysis suggests that a freak event such as an extreme storm or a plague was to blame.
The findings counter a previous theory that harmful genetic mutations caused by inbreeding led to a “genomic meltdown” in the isolated population. The latest analysis confirms that although the group had low genetic diversity, a stable population of a few hundred mammoths had occupied the island for thousands of years before suddenly vanishing.
Dalén and colleagues analysed the genomes of 13 mammoth specimens found on Wrangel and seven earlier specimens excavated on the mainland, together representing a span of 50,000 years.
The findings, published in Cell, reveal that the Wrangel population went through a severe bottleneck, reduced to just eight breeding individuals at one point. But the group recovered to a population of 200-300 within 20 generations, which appears to have remained stable until the very end.
Similar thing for First Nations people in Australia. Many species died out when they first moved to australia.
I understand the reluctance for people to call it out as it can get used as a club to attack First Nations people. Who, later, lived in balance with the wildlife until white colonists arrived.
So pointing the finger at First Nations gets used as an excuse to ignore all the destruction that colonisation of Australia resulted in.
We should be able to talk about it but i understand why it is a sensitive issue in Australia, New Zealand and America.
The Māori definitely killed off the Moa bird. No doubt about that. I’m not sure why it’s so politically charged to admit to the same about other megafauna extinctions.
The timeline is much more definitive with the Māori because it only happened in the past few hundred years. Megafauna extinction and human habitation in Australia is tens of thousands of years ago, and we dont really have a very precise time for either event, much less evidence that they coincided
It's so weird. The people alive today didn't do those things, the people alive back then did. People act as if what someone's ancestors did is what they are literally doing right now, which is obviously ridiculous.
Because it’s not relevant to this paper nor is it a proven hypothesis at this point. Humans didn’t verifiably arrive on Wrangel until after the mammoths had died out. And a severe bottleneck and subsequent recovery are not consistent with predation.
It is complex. In most cases, human expansion into new areas happened at the same time as climate shifts. There are definite cases where human predation was the main factor, and cases where it was not. For Eurasia, if I’m not flipping them in my head, the wooly rhino and the mammoth are a good example of that dichotomy. The mammoth steppes were a vast expanse of open terrain with abundant forage, but it was not the prairie grasses that modern people think of as being standard. Those C4 grasslands are in many ways a modern phenomenon, and they have a very different nutritional profile for grazers compared to the mammoth steppe, which had a lot more forbs, and was dominated by C3 photosynthesis.
The demise of the mammoth was largely caused by the end of the ice age, and an ecological transition that removed the food source they were dependent on. A huge animal can only exist with a reliable source of its preferred food.
However, hunting pressures on an already stressed population can not have helped, and it is also thought that the woolly rhino would have been fine, if we hadn’t eaten them all.
This was the case for many megafauna. I think one good piece of evidence is elephants. Despite human presence, they have not gone extinct, because they did not face the same habitat loss. They have had more recent problems caused by humans, but if they were easily made extinct by humans with spears, this should have happened thousands of years ago.
So, it can be complex. I’m pretty sure the Māori killed the Moas, and I suspect the native horses and camels of North America also largely fell to hunting pressure, while the mammoths and mastodons were probably just on their way out. Giant sloths could go either way, but I suspect hunting was a big factor.
However, I have not seen the same reluctance to credit native people’s with extinction as you imply. It has clearly happened, many times, it’s just obvious.
I mean, I doubt it's so much a reluctance to say it, as it is a reluctance to publish that in a peer reviewed paper.
And that's okay, in my mind. In the softer sciences, there might be something that basically the whole community agrees is likely what happened; but there's no direct evidence for. I think in that case it's probably prudent not to talk about it like it's fact.
A recovery to 200 is good, but that doesn't sound like a complete recovery. Whatever the bottleneck wad, it was still affe ting them most likely ( though it could be two unrelated pressures)
Well yeah it's kind of silly to think that ancient people were stupid enough to think that completely eradicating their largest source of food and basically everything else just for fun was a good idea. I'm sure they didn't help, but still.
>silly to think that ancient people were too stupid to think that completely eradicating their largest source of food
I believe modern people do the same as long as there is a profit motive. Ancient people maybe had a different points system than ounces of gold or a central bank currency, but I don't see why the game would be fundamentally different.
Humans didn't get to Wrangel Island until the mammoths there had died out. We've driven a lot of animals to extinction, but the Wrangel Island mammoths, no.
I don’t think that is true. Earliest human remains found on Wrangel are a few hundred years later than the last mammoth, but human remains are hard to find. Humans certainly played a major part in mammoth extinction elsewhere, the only reason the mammoths survived on Wrangel is humans didn’t make it there.
As of now, we see humans got there 10000 years after other parts of N America and 200 years after the mammoths went extinct. Very likely to find some slightly earlier evidence of humans that exactly lines up with the last mammoths.
Still wouldn’t explain the bottleneck and recovery. It’s plausible that they did kill the last of the mammoths, but that’s not what this paper is about.
Eh. Give ancient people a gun or other easy method to hunt and the knowledge on how to use it pretty sure their primary animal food source is soon drastically over hunted and probably killed off as well. The limiting factor on human 'greed' for ancient or tribal people isn't some sort of noble savage impulse or something it's lack of technology to do the same thing enmasee. Humans are pretty much all the same in that regard. It's knowledge of how that's a bad thing to do environmentally and for that long term profit and stability thing that we don't do it more now.
Welcome to r/science! This is a heavily moderated subreddit in order to keep the discussion on science. However, we recognize that many people want to discuss how they feel the research relates to their own personal lives, so to give people a space to do that, **personal anecdotes are allowed as responses to this comment**. Any anecdotal comments elsewhere in the discussion will be removed and our [normal comment rules]( https://www.reddit.com/r/science/wiki/rules#wiki_comment_rules) apply to all other comments. **Do you have an academic degree?** We can verify your credentials in order to assign user flair indicating your area of expertise. [Click here to apply](https://reddit.science/flair?location=sticky). --- User: u/mvea Permalink: https://www.theguardian.com/science/article/2024/jun/27/last-woolly-mammoths-arctic-island --- *I am a bot, and this action was performed automatically. Please [contact the moderators of this subreddit](/message/compose/?to=/r/science) if you have any questions or concerns.*
I believe all modern cheetahs are similarly descended from just 12 individuals. Too bad the mammoths couldn’t make a strong recovery.
for a second I thought you were saying that it was your personal belief that 12 cheetahs started the species, rather than saying that you recalled that fact from somewhere, and I thought to myself “what an odd thing to share”
we're putting the work in to make sure cheetahs go back whence they came though.
What's scary is there is evidence humans dropped to like a couple thousands in population during the last Ice Age
i think that was the Toba eruption event, much longer ago.
Imagine if the Wrangell Island Woolly mammoths survived the extinction event. You would probably have a headline like this: "The Wrangell Island Woolly mammoths were discovered in 1820's by joint European-American arctic expedition team. They became rare by 1860's as new settlers to the Island began hunting them for meat, fur, and ivory. By 1890 the last mammoth was shot by a drunk prospecter who decided it would be fun to shoot something after a night of drinking whiskey and gambling with the boys. Here is picture of Gergory Horton holding his Winchester Rifle and standing proudly atop the dead mammoth, which was a pregnant female. The mother and her fetus were later shipped to the London Museum of Natural History and put on display."
This is basically the great Auk but with the north Atlantic instead of Wrangel islands
And the Dodo.
Dodo hunting is more myth than reality, it was introduced predators that wiped them out.
The Dutch used them as an easy source of food, and the introduced rats ate the eggs. Your right though, there wasn't really much hunting needed though. Islands species living on remote islands don't have fear of humans. Dodos had no natural predators prior to humans. The Falkland Island wolf for another example swam up to the first human colonists greeting them with wagging tail. They did not run from humans and so were easy to kill. Humans clubbed many of them to death.
It was pigs rooting for their nests and eggs.
Yup, and rats, and some other animal whose name escapes me
Jellyfish probably.
Those damn jellyfish, eating all the endangered eggs.
Housecats may look harmless but their species kill more animals every year than any other (non-human) and it's not even close.
Yeah, spay, neuter, and keep your kitties inside. They're still vicious little murderers, but at least indoors they're only murdering the animals that don't have the sense not to go into the murder house.
Where I live outdoor kitties routinely get murdered by coyotes.
Yeah coyotes got a couple of my in-laws' cats. :( And even in areas without coyotes, outdoor cats have a significantly shortened life expectancy due to cars, parasites, and bigger, meaner cats.
The number is thought to be 30+ billion animals annually.
In the United States, over 1 million vertebrate animals are killed by vehicle collisions every day. Globally, the number amounts to roughly 5.5 million killed per day, which when extrapolated climbs to over 2 billion annually. My cat does nothing compared humans
in the united states, roughly 1 billion birds and 6 billion mammals are killed by free range cats annually
Why do you think this is relevant? Cars do damage. Cats do damage. That’s like saying if I only shot and killed one person, it’s nothing because Stephen Paddock.
Because I have never seen people bitching about cars, but anytime a cat is mentioned someone is always saying keep your cats indoors. I am saying stop driving cars if you actually care about the environment.
False equivalence. People need to drive cars to live. Your cat doesn't need to be let outside to live. This is like people complaining about the CO2 emissions of concrete in nuclear power plant construction as a reason not to build them. It's a completely misleading argument meant to draw attention away from the actual problem of fossil fuel consumption.
I was also thinking about the Thylacine (Tasmanian Tiger). It got shot, poisoned, and trapped into extinction by ranchers. Even though the animal did not kill livestock.
Yep. And the last known living one died of Hypothermia because the zoo keeper forgot to let it into its night enclosure. Poor thing. The photos of it haunt me.
I hold out a small glimmer hope that maybe few are still out deep in the Tasmanian bush and one day we find them and start breeding programs.
Me too. Some people who've hiked the remote regions in Tasmania claim that they still exist but refuse to tell anyone where they saw them. It gives me hope. Let them rebuild in privacy as long as possible before we rediscover them and start breeding programs and set up protective fences and the like.
That's a possibility as well. Perhaps there have been some found, and they are closely monitored with the location being kept secret.
As a Tasmanian; no... no chance sorry. The first and biggest issue is that Tasmanian tigers were Midland creatures. The midlands is now completely given over to pasture. That's also why all Tasmanian emus are gone. The landscape they had adapted for was entirely erased, and enclosures removed their ability to move to and from any scattered foliage that our idiot ancestors had failed to eradicate in their vendetta against all things living. The midlands is now basically a desert for most of its breadth. The mountainous rainforest plateau is undeveloped... But is a completely different biome to the bushland that the tigers lived in. It's high altitude, extremely cold, extremely wet, with totally different animals and ecosystems It's basically like taking an ostrich out of savannah and putting it in an alpine skiing retreat. It isn't going to survive. They can't cross those mountains, and even if they could, the weather conditions on the other side of the range are too extreme for them. That's why that side of the island is almost unpopulated; it's too extreme for anything except for absolute niche creatures to live in. It was used as the site for the most remote prison colony because it was (nearly, with a few high profile exceptions in the brief nice times of year) guaranteed to kill anyone who left shelter. Sadly, that applies to the animals too. You have to be specialised to survive year round. Furthermore, having grown up in those temperate rainforest regions, there is absolutely no way you could maintain a secret location away from the population centres. There aren't the necessary roads and infrastructure; the tracks are all well known and widely used with no detours or opportunities for 'secret' routes anywhere. Every single one is known and used often by hunters, forestry workers, campers and hikers. Tasmania isn't that big, especially next to mai land Australia; there isn't a large space for things to hide in. I've been camping with friends and we heard sounds, absolutely. But it was just plain hope; there are countless groups, people and bodies who desperately hope the Tiger is still out there somewhere and would do anything in their power to bring them back... But it isn't out there. It's gone.
From what I remember they're the animal we are most likely able to clone out of extinction, something to do with having the most intact DNA sequences out of all the extinct animals we could possibly clone.
It'll be tricky; none of our cloning techniques have been developed for marsupials, and there's some very key differences between marsupials and placental mammals. That's one of the reasons the thylacine cloning program is getting so much support, because even if it fails (and lots of experts expect it to fail) the techniques that need to be developed for it should be useful to save currently endangered marsupials.
I believe there's a couple of animals from the family that Ostriches, Emus, Kiwis and Cassowaries belong to that we also have pretty much entire DNA sequences for. So those two are also on the cards.
Auk? That reminds me, we did the same to Aurocks. https://en.wikipedia.org/wiki/Aurochs
Holy hell. I didn't know they held on until the 1600's. That somehow hurts more than had they died off 4000 years ago.
In a way, they're not actually extinct. Cows are just domesticated Aurochs.
Yep, they were basically hunted to extinction in the mid 1800's for their feathers, meat, and oil. The Galapagos Giant Tortoise was also hunted to extinction due to the fact that it was, apparently, delicious. Of the 12 surviving subspecies (of the original 14 or 15), several are currently endangered.
And probably delicious. Endangerously delicious, if you will.
No way they would have survived 70 years after discovery. Europeans killed off the estimated 2000 Stellar's sea cows only 27 years after discovering them.
Stellars sea cows were, by all accounts, delicious
Ancient humans went through all the trouble of hunting mammoths They must have been delicious!
To be fair, they were pretty much on the way out anyway. Turns our raising sea levels had cut them off from their typical range and they were already dwindling. Humans were just the final nail in the coffin.
How would rising sea levels stop them from swimming somewhere? Wouldn’t that just expand their available area?
Do you see manatees everywhere there's water? Sea Cows were in the same family. They had preferred ranges, and also they were herbivores so the plants they eat grow in particular conditions. In a
And do we see manatees preferred ranges shrinking as sea levels rise? Obviously a species isn’t going to use the entire ocean, I’m asking why the ocean being bigger would cause them to want less space.
Think of it this way. Say your a group of people living in an archipelago where the islands are "connected" by relatively shallow seas where plenty of fish gather, in addition to other marine life (seaweeds, moluscs, and shorebirds). The people living there don't have boats or the ability to make them, they're manner of moving from island to island is literally swimming through the shallow seas, and some of the islands are far enough away that this is time consuming and somewhat dangerous. If the sea level rose 20 feet, then the distance gets farther. Also while they still have access to shallows where they can Harvest food, if they deplete an area it is now more difficult (or potentially not possible) to move between islands. This is basically the situation that Sea Cows were in. Stuck in an area they couldn't leave where they would be especially susceptible to any changes in their local food supply. For more information, look at Wikipedia. They have a section called "Dead Clade Walking" and "Extinction Debt" that goes into better detail.
“The mammoth’s tusks were mounted on a tree ring from the largest and oldest known Redwood he chopped down on a prospecting trip to California in an old growth forest. The rest of the tree was used to build a cabin for loggers.”
Easier to imagine humans killing the last of these great beasts than them surviving till modern times.
It would be difficult for a large and isolated population of megafauna to survive humans in the age of gun powder. Even now, remaining large animals are being killed in huge numbers for profit, due to habitat loss, and by the agricultural cartels. For example, lions used to be native to Europe. Not even talking about the ice age. I'm talking more recently, like the bronze age. Greek scholars like Herodotus wrote about lions in Greece. There are even ancient Greek artworks depicting chariot riders hunting lions.
As a layman, I’d be interested to better understand how it got down to just 8 individuals. Do they know how many males & females?
I'm guessing since they only analysed the remains of 13 specimens that it's based on genetic variance of each sample and charting then against time. Kinda like when people do a DNA test and they tell you how much of your DNA matches your dad/mom/sister/cousin
[https://en.wikipedia.org/wiki/Younger\_Dryas\_impact\_hypothesis](https://en.wikipedia.org/wiki/Younger_Dryas_impact_hypothesis) This theory has really caught my eye mostly because there are a whole bunch of things that all happened pretty much at the same time. Goblekii Tempe was also in this time frame. There is still some healthy debate about it, but I lean towards this side as we learn more.
It’s goofy pseudoscience for rubes. There is no “healthy debate” amongst actual scientists.
They have different samples dates from different eras and compared the observed heterozygosity of the earlier samples to the more recent samples. Then they simulated 108 models with varying severity of bottlenecks and recoveries and found the best fitting models to be those with a bottleneck of 8 Ne (effective population size) individuals. Only a bottleneck of that severity resulted in the closest fit for loss in observed heterozygosity.
I’ve linked to the news release in the post above. In this comment, for those interested, here’s the link to the peer reviewed journal article: https://cell.com/cell/fulltext/S0092-8674(24)00577-4 From the linked article: The last woolly mammoths on Earth took their final stand on a remote Arctic island about 4,000 years ago, but the question of what sealed their fate has remained a mystery. Now a genetic analysis suggests that a freak event such as an extreme storm or a plague was to blame. The findings counter a previous theory that harmful genetic mutations caused by inbreeding led to a “genomic meltdown” in the isolated population. The latest analysis confirms that although the group had low genetic diversity, a stable population of a few hundred mammoths had occupied the island for thousands of years before suddenly vanishing. Dalén and colleagues analysed the genomes of 13 mammoth specimens found on Wrangel and seven earlier specimens excavated on the mainland, together representing a span of 50,000 years. The findings, published in Cell, reveal that the Wrangel population went through a severe bottleneck, reduced to just eight breeding individuals at one point. But the group recovered to a population of 200-300 within 20 generations, which appears to have remained stable until the very end.
When did humans arrive on Wrangel?
I bet 4,000 years ago.
There is something within anthropology culture recently that prevents them from saying the obvious about prehistoric megafauna extinctions.
Similar thing for First Nations people in Australia. Many species died out when they first moved to australia. I understand the reluctance for people to call it out as it can get used as a club to attack First Nations people. Who, later, lived in balance with the wildlife until white colonists arrived. So pointing the finger at First Nations gets used as an excuse to ignore all the destruction that colonisation of Australia resulted in. We should be able to talk about it but i understand why it is a sensitive issue in Australia, New Zealand and America.
The Māori definitely killed off the Moa bird. No doubt about that. I’m not sure why it’s so politically charged to admit to the same about other megafauna extinctions.
The timeline is much more definitive with the Māori because it only happened in the past few hundred years. Megafauna extinction and human habitation in Australia is tens of thousands of years ago, and we dont really have a very precise time for either event, much less evidence that they coincided
It's so weird. The people alive today didn't do those things, the people alive back then did. People act as if what someone's ancestors did is what they are literally doing right now, which is obviously ridiculous.
Because it’s not relevant to this paper nor is it a proven hypothesis at this point. Humans didn’t verifiably arrive on Wrangel until after the mammoths had died out. And a severe bottleneck and subsequent recovery are not consistent with predation.
It is complex. In most cases, human expansion into new areas happened at the same time as climate shifts. There are definite cases where human predation was the main factor, and cases where it was not. For Eurasia, if I’m not flipping them in my head, the wooly rhino and the mammoth are a good example of that dichotomy. The mammoth steppes were a vast expanse of open terrain with abundant forage, but it was not the prairie grasses that modern people think of as being standard. Those C4 grasslands are in many ways a modern phenomenon, and they have a very different nutritional profile for grazers compared to the mammoth steppe, which had a lot more forbs, and was dominated by C3 photosynthesis. The demise of the mammoth was largely caused by the end of the ice age, and an ecological transition that removed the food source they were dependent on. A huge animal can only exist with a reliable source of its preferred food. However, hunting pressures on an already stressed population can not have helped, and it is also thought that the woolly rhino would have been fine, if we hadn’t eaten them all. This was the case for many megafauna. I think one good piece of evidence is elephants. Despite human presence, they have not gone extinct, because they did not face the same habitat loss. They have had more recent problems caused by humans, but if they were easily made extinct by humans with spears, this should have happened thousands of years ago. So, it can be complex. I’m pretty sure the Māori killed the Moas, and I suspect the native horses and camels of North America also largely fell to hunting pressure, while the mammoths and mastodons were probably just on their way out. Giant sloths could go either way, but I suspect hunting was a big factor. However, I have not seen the same reluctance to credit native people’s with extinction as you imply. It has clearly happened, many times, it’s just obvious.
I mean, I doubt it's so much a reluctance to say it, as it is a reluctance to publish that in a peer reviewed paper. And that's okay, in my mind. In the softer sciences, there might be something that basically the whole community agrees is likely what happened; but there's no direct evidence for. I think in that case it's probably prudent not to talk about it like it's fact.
4001 years ago
Those last 8 tried their best.
Read that as "gnomic meltdown" and instantly started to have horrific flashbacks.
The plague was us, humans, there’s plenty evidence of prehistoric human civilization on the island.
Wouldn’t really match the genetic data which indicates a post bottleneck recovery. Consistent predation would be more in line with a steady decline.
The evidence of human activity starts at around the time the mammoths disappeared.
A young wooly mammoth and an old wooly mammoth are sitting on top of a hill…
how do the Paleontologists know wooly mammoths didn't all just die from natural causes?
A recovery to 200 is good, but that doesn't sound like a complete recovery. Whatever the bottleneck wad, it was still affe ting them most likely ( though it could be two unrelated pressures)
What ever reason they come up with, needs to explain all the mammoths that were suddenly deep frozen in their place, or their theory is not right.
8 Wooly mammoths were probably all closely related… let’s hope that they didn’t have too much memory of the matings…
Well yeah it's kind of silly to think that ancient people were stupid enough to think that completely eradicating their largest source of food and basically everything else just for fun was a good idea. I'm sure they didn't help, but still.
>silly to think that ancient people were too stupid to think that completely eradicating their largest source of food I believe modern people do the same as long as there is a profit motive. Ancient people maybe had a different points system than ounces of gold or a central bank currency, but I don't see why the game would be fundamentally different.
Humans didn't get to Wrangel Island until the mammoths there had died out. We've driven a lot of animals to extinction, but the Wrangel Island mammoths, no.
I don’t think that is true. Earliest human remains found on Wrangel are a few hundred years later than the last mammoth, but human remains are hard to find. Humans certainly played a major part in mammoth extinction elsewhere, the only reason the mammoths survived on Wrangel is humans didn’t make it there. As of now, we see humans got there 10000 years after other parts of N America and 200 years after the mammoths went extinct. Very likely to find some slightly earlier evidence of humans that exactly lines up with the last mammoths.
Still wouldn’t explain the bottleneck and recovery. It’s plausible that they did kill the last of the mammoths, but that’s not what this paper is about.
They did it to giant sloths in North America.
When you have enough food to eat, you have 100 problems. When you don't, you have one problem, and "let's not eradicate this animal" isn't it.
Bad take, we extinguished quite handidly and recently the passenger pigeon in North America. It’s just human stupidity
That....was a couple hundred years ago??? What?
It sure was, buddy
It doesn't really matter how long ago it was, to disprove your point.
Eh. Give ancient people a gun or other easy method to hunt and the knowledge on how to use it pretty sure their primary animal food source is soon drastically over hunted and probably killed off as well. The limiting factor on human 'greed' for ancient or tribal people isn't some sort of noble savage impulse or something it's lack of technology to do the same thing enmasee. Humans are pretty much all the same in that regard. It's knowledge of how that's a bad thing to do environmentally and for that long term profit and stability thing that we don't do it more now.
We still have like 40% of humans believing that climate change isn't real.