End of the Megafauna with Ross MacPhee - AMNH SciCafe

You’ve probably heard of woolly mammoths and giant ground sloths-but what about gorilla-sized lemurs and 500-pound birds? Beginning about 50,000 years ago, many of these strange animals-megafauna-went extinct.
Ross MacPhee, curator in the Museum’s Department of Mammalogy, uses colorful illustrations to take us on a journey back in time to the world of the “megafauna,” and explains what scientists think may have happened to them.
To listen to the full SciCafe talk, including Q&A, download the Science@AMNH podcast on iTunes, Soundcloud, or wherever you get your podcasts.
Or listen here: www.amnh.org/explore/news-blo...
This SciCafe took place at the Museum on December 5 2018.
#Extinction #Mammoth #Megafauna #Pleistocene #AMNH #SciCafe #Paleontology
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[@patrickbrownrigg1058]

The ecological zonation for ~25,000 years ago chart reflects coastlines for the present day. A chart showing the coastlines when the level then was ~400’ lower than now would be another interesting perspective. Thanks, great stuff here

[@avencebi]

I think it's ridiculous to just consider the over hunting theory not only do I not believe that they hunted random species to extinction but there were other beasts here that humans would have encountered like the short faced bear and American lion that would've been terrible for early humans to run into...something dramatic definitely happened 12,000 years ago that changed the history of the planet

[@TonyTrupp]

Carnivores like the lion and bear may have also come under increased pressure by competing with humans for common game animals. Human’s wouldn’t have necessarily needed to hunt them directly. There’s also a lot of other areas of the world that had megafauna species wiped out as humans arrived, not coinciding with rapid climate change. For example the moas of new zealand being wiped out by the polynesians a few hundred years ago, or the megafauna of australia being wiped out when humans and dogs arrived there after the land bridge formed from papua new guinea. Or the giant sloths that died off in caribbean islands thousands of years after they disappeared on the mainland, also coinciding with human’s arrival.

[@avencebi]

I see you guys points about Human technology (spears/ranged weapons) and examples of extinct by humans (moa/ giant sloth). Humans certainly put pressure on the other species but again to claim they were the major reason I think gives humans too much credit we are talking about major megafauna from North/ south america and Europe/Asia not just isolated creatures in New Zealand some of these animals were already exposed to human like creatures so they would've known to fear humans and not just stand there like the dodo etc...idk if you guys have seen the recent study but scientists now claim that some of the megafauna like mammoths and wooly rhinoceros actually lived thousand of years after what they originally claimed saying wooly mammoths survived in mainland until after the pyramids were built only disappearing after the climate/environment they lived in cease to be leading to their demise.

[@TonyTrupp]

@@avencebi those megafauna lived through about 20 glaciation cycles over millions of years, many of which were just as extreme as this last one. And yet those others didn’t cause a massive extinction of megafauna like this last one. That should tell you it wasn’t just climate. Humans really were a new kind of predator, able to hunt in groups, setting grasslands on fire, throwing spears from a distance. You can watch videos online of africans killing hippos and elephants with spears. The large size of the megafauna would have no longer protected them from thrown spears via atlatls. The slow reproduction rates of those large animals made them more susceptible to eventual over-predation. There are also multiple studies in both north and south america that show major pulses of extinction corresponding right when there’s a massive spike in the number of large clovis or fishtail spear points. Those spear points then rapidly declined in frequency after that extinction pulse. This occurred in south america about 400 years after north america, as would be expected as the human population took time to grow further south.

[@wegojim5124]

We hunted their prey to extinction.

[@21LAZgoo]

@@TonyTrupp humans have been doing that in africa longer than anywhere else, yet they still have all their megafauna

[@tomasfrybl3597]

After this video I went to Joe Rogan's show with Graham Hancock and Randall Carlsson.

[@AggressiveMediocrity1]

When randall starts with his slides, I listen.

[@21LAZgoo]

@@AggressiveMediocrity1 *YE.*

[@airmark02]

Yes

[@wbbartlett]

Because when you want rational scientific input, Hancock is the first person you should turn to 🙄

[@ericvulgate]

most of human history is sitting on the continental shelves offshore.

[@tothetruthandbeyond4510]

eric vulgate yeah, you're right. I still 110% believe that an asteroid hit earth.

[@Bix12]

@@tothetruthandbeyond4510 And you'd be right, too...actually, i think it's the debris field of a huge asteroid which broke apart and it now inhabits a portion of the sky in the general direction of the Tauris constellation...and the Earth passes through this debris field like clockwork, although I cannot recall how many years that is...but it is extremely dangerous for our little blue marble. However, Dr Robert Schoch, Harvard trained geologist who pointed out the massive amount of rain-water caused erosion in the enclosure from which the Sphinx was wrought, thinks it might've been a series of solar plasma flare-outs around 12,800 years ago rather than an asteroid impact. This was a few years ago...there is more evidence for an impact now.

[@Koofuku1ce]

@@tothetruthandbeyond4510 The Younger Dryas period was almost certainly the aftermath of the 1.5 km across iron asteroid that hit in the Hiawatha Glacier, Greenland approx. 13000 years ago. It was a huge cataclysmic event, flinging rubble and boulders into the atmosphere which would then rain down to earth like in all those ancient texts when it rained fire from the heavens, melting lots of glacial ice, causing floods, turning 9% of the earth's biomass into an inferno, killing civilizations and turning many animals and megafauna extinct. You will find no skeletons of megafauna in north america above the layer of ash.

[@vanglhun]

yep just a few metres in rise of seawater and boom😂

[@jbyrd655]

'Bout the only thing worth saying regarding this opinion is how undefined and easily refuted it is. Have you ever looked at an ice age land area map?

[@TheCam4]

Overgrill brought about overchill followed by overkill. Hah!

[@livefire666]

That makes perfect sense actually, humans had to survive the cataclysm as well, so being picky how much you kill in those times would of been less a concern. Humans at that time would of been convinced its the end of the world happening around them just as they would if they were around to witness the KT event. Is there any cave drawings of this impact happening? You would think there would be by the humans then..

[@21LAZgoo]

@@livefire666 some scientists say some drawing on a pillar in gobeklitepe represents an impact

[@sent4dc]

2:00 wow, I just realized something. My friend Tyler is a mega-fauna and I'm not :( he's definitely over 100 lb.

[@OMGAnotherday]

sent4dc - Hehe - Don’t eat him! 😂✌️👍🏼✊🏼

[@morpen1234]

Most humans are. 100 lb is around 45kg

[@MarvinMonroe]

You weigh less than 100 pounds?

[@donaldplaysyertrousers134]

@@MarvinMonroe no. I'm a man

[@2degucitas]

Whoever put the screen up behind the speaker is brilliant. It was so distracting before.

[@jackspratt2001]

Seems to me that the younger Dryas impact is pretty well proven.

[@klikssiikubra314]

It's really not

[@surfk9836]

Sorry but no. Hancock has purposely left out contrary evidence from his readers. His critics have stronger evidence contrary to his assumptions.

[@jollyroger7624]

@@surfk9836 it was scientists that put forward the theory, Hancock came later. The evidence is obvious, science is slow, or debilitated if you like !?

[@J.Millhouse]

SurfK9 such as? I’m not agreeing with either side, just tired of seeing people claim knowledge of evidence where they have none *edit: minor spelling error adjusted

[@chriscottrell641]

@@surfk9836 I highly suggest you, and anyone else reading this, to look up the running bibliography for all papers published on the Younger Dryas over the past decade or so. The evidence in support of an extinction level impact event is getting to be overwhelming.

[@ClarkSpark77]

There is no reasonable way tribes of hunters wiped out all of the giant sloths, mastodons, mammoths, giant beavers, short-faced bears, freakin camels, horses, saber-toothed tigers, etc. across two continents. "Megafuana wouldn't recognize human hunters as a threat", is verging on comical as a sensible argument for overkill. Apparently hunters would be able to saunter up to the saber tooth/mammoth etc. and slice his throat. Makes zero real world sense. Hunter tribes had no survival incentive or capability to wipe out the entirety of all the largest mammals in their world. The black mat geological layer is the evidence and the smoking gun. Impact markers like nano-diamonds, melt glass, and spherules are found in the black mat layer and they are formed during bolide impacts to our planet. Most people aren't ready to hear the implications of this... But the evidence for the catastrophic meteor(s) strike on the Laurentide ice sheet 12,800 years ago is overwhelming. Occam's razor says so.

[@jeupater1429]

Agreed. By this guys own data: Human enter eurasia 250,000 yo. Megafauna goes extint there 12,000 yo. His conclusion: "The coupling of the arrival of humans and megafauna extinction gives particular strength to the overkill argument!" Yeah, the coupling of a 238,000 year difference. What the hell is he smoking

[@justmenotyou3151]

Anthony zamora has videos about an impact on the ice sheet around the Great Lakes, resulting in secondary ice impacts forming the Carolina bays and Nebraska Rainwater Basin. The megafana would have been pulverized. Makes a lot of sense.

[@tinhlam2826]

Dude you need to remember. Without hunting megafauna, no small animal or plant would be enough to feed these large numbers of people.

[@orpheusmorphius2624]

Incredible lecture on the topic I'd buy his books

[@spencergellsworth]

Fantastic book & fantastic speaker

[@paninidagoat8780]

I wish he would make a book about the world without humans and have peter schouten back for great illustrations and focus on new areas like the Everglades or Indian rivers, or southern europe, to name a few areas and take us through a human free world

[@pookie4660]

In the past 6 months two Greenland craters have been found. The latter just a week ago. Further the ice samples from North Pole/Greenland pulse 1 data shows a almost unbelievable sea level rise. Interesting that megafauna seem to drop like flies around this same time.

[@AmericanMuseumofNaturalHistory]

Dr. MacPhee addressed the Hiawatha crater of Greenland in the full version of his talk. If you're interested, you can hear it on our podcast! www.amnh.org/explore/news-blogs/podcasts/podcast-scicafe-end-of-the-megafauna-with-ross-macphee

[@glengravel]

the floods that happened 12,000 years ago - caused such world wide devastation that 1-2-3-4 perhaps even more impacts would not have been enough - the better theory is a celestial body from outside our system strayed past the earth and adding it's pull to that of the moon - caused all the water on the earth to flow over to one side (like it does in smaller amounts when it's just the moon) and the water stayed there - while the planet kept spinning only subsiding when the extra-celestial body moved it's gravitational pull far enough away to longer affect the earth

[@dd_2023]

@@glengravel Annunaki story ..many mud floods and apocalyptic fires, as recently as 1815. Research mud floods and millennial reign

[@pookie4660]

@@AmericanMuseumofNaturalHistory Never saw this reply. Appreciated and will watch in the next week. Cheers!

[@21LAZgoo]

well, one of those craters has been dated to 58 million years ago, although i dont think this disproves the impact hypothesis at all

[@johnortmann3098]

There's a fourth factor rarely mentioned: When humans arrived in a new place the took control of and completely changed the fire regimens. This in turn altered, destroyed and created new ecosystems.

[@wegojim5124]

That goes under overkill i guess

[@21LAZgoo]

sudden increased wildfires, loss of freshwater, the landscape becoming much more arid and the quick disappearance of grasslands made the megafauna very quickly collapse and go extinct in australia around 40,000 years ago, humans arrived 25,000 years prior to that and nothing bad happened to the megafauna. Obviously the megafauna were definitely hunted in that timeframe, but the population was stable until around 40,000 years when it started to suddenly collapse also neaderthals and the elasmotherium which is the 2nd largest rhino that ever lived, went extinct around this time too

[@bkjeong4302]

@@21LAZgoo Ground sloths were, for the most part, not grassland animals; in fact they BENEFITTED from grassland being lost to woodland, as most were browsers or mixed feeders. This whole idea that megafauna were grassland animals as a whole really needs to die. Some were, but others were animals of more vegetated and warmer habitats and thus were actually set up to benefit from a warming climate (and did indeed increase during prior interglacials). American mastodons, Smilodon, and most of the Australian megafauna (save the giant stenurithine kangaroos) were also animals of warmer, wetter, more vegetated environments.

[@21LAZgoo]

@@bkjeong4302 thats true, i was just talking about the megafauna in australia in that comment. also this video says that the reasons there were very few extinctions in africa and south asia is because of coevolution with hominds, but homo erectus arrived in europe at the same time it did in south asia yet most of the megafauna in europe still went extinct at the end of the ice age

[@bkjeong4302]

@@21LAZgoo Europe (and Eurasia in general) wasn't hit nearly as badly as the Americas or Australia-only around 30% of Europe's Pleistocene megafauna went extinct.

[@richardsleep2045]

Thanks for this balanced explanation/introduction.

[@OMGAnotherday]

Richard Sleep - I was waiting for the put down on ovegrill, pleasantly surprised on the outcome of this presentation.

[@21LAZgoo]

@@OMGAnotherday well, the overgrill that happened 14800 years ago did cause a huge sudden population collapse in the megafauna because the bolling allerod

[@dave9351]

Excellent presentation

[@zenonpinezka]

Great summary at the end.

[@iambodybuildingyt221]

Great video

[@karenspivey9420]

I was there! Loved it!

[@Bootrosgali]

Theres only 9 mins left and he is only getting going ,, is there a part 2!

[@istitutodigemmologiagenova1976]

Merry Christmas to you all !

[@nickcullen4567]

the missing bodies and bones could possibly have been used for tools or other things perhaps? evidence in native weapons show the use of animal bones and teeth for weapon enchantment from the basic club to spear heads, also jewelry which could also be a way to explain how people find random fossil pieces scattered all over as they may have been dropped by the owner? even perhaps a percentage ground down for shamanism practice and so forth fertility from eating a crocs balls or so forth. to reinforce the overkill theory at-least

[@KR-tu1kh]

Good call on the crocs balls. I suppose after killing a mammoth, it was customary to drag into the arctic and bury in the tundra. I'm surprised there aren't any large roads left from all the hauling, being that millions of animals are buried around the arctic.

[@dd_2023]

all the bodies from mud floods are missing ... yet, we just discovered 12 individuals, shackled & executed, that were 2,000+ years old. Where are the millions of bodies from the mud floods? Jewelry, tools? Millions, possibly billions? Can you see where your theory might be flawed?

[@justmenotyou3151]

Anthony zamora has videos about an impact to the ice sheet around the Great lakes, resulting in secondary ice impacts forming the Carolina Bays and Is Nebraska Rainwater Basin. It would have pulverized the North American fana. Makes a lot of sense.

[@VashLoot]

What puzzles me about all of this is the fact that we still have too few ancient human remains. According to this we existed 250,000 and we have more mega fauna bones than we do human. 2nd thing that still about all of this is that Africa, didn't experience that much mega fauna death. How is that possible if it is partially blamed on human overkill?!

[@21LAZgoo]

they said it was because hominds coevolved with the megafauna in africa and south east asia, but the earliest hominds like homo erectus that arrived in south asia arrived in europe at the same time yet most of the megafauna in europe still went extinct at the ending of the ice age

[@VashLoot]

@@21LAZgoo Nah. That just sounds like an excuse. Like Honestly, because they grew up with them? Really? The other thing that doesn't make sense is the lack of Neolithic evidence in Africa. There are bones but not enough to say extended period of time in 100,000k years. There is a great lack of data from anyting before 32000k bce. The archeological data seems to be missing a great lot from this period of time.

[@21LAZgoo]

@@VashLoot bro i agree with you lol i dont think humans overkilled the megafauna either, what i said above was a reason that overkill advocates give to why megafauna in africa and south asia was nearunchanged, and based off of early hominins being found in europe at the same time as they are in south asia, and i also found out that some of those hominins found in europe were even older than the ones found in africa, i think this proves overkill to be even more wrong

[@justmenotyou3151]

​@@VashLoot most evidence was along the Palocoast which were drowned. Evidence lost.

[@akashs8819]

Some of the elephants are bigger than the mammoths.

[@dutchieee6465]

Weren't humans now found to be in the ''New World'' as far as 130 thousand years ago?

[@nmarbletoe8210]

possibly Denisovan

[@wlhgmk]

Just a wee niggle. If we are going to call the icy period between the Emian interglacial and present Holocene interglacial, then we have to coin a new term for the 2.75m year period in which there were around 50 cycles between glacial and interglacial periods.

[@psycotria]

Ice Age. I tell people the fact that we are still in an ice age now.

[@matthewstorer8236]

Exactly! Thank you. Nobody ever mentions this!

[@21LAZgoo]

that Eemian period nearly made mammoths go extinct, if the younger dryas impacts happened right after that period what happened 12900 years ago wouldve happened then

[@IMakeThingsonPaper]

why was the segment on over grill or impactor edited out of this video?

[@OMGAnotherday]

J Potts - There was enough in the presentation and accepting of overgrill. They didn’t dis the idea.

[@AggressiveMediocrity1]

There was an impact crater found in Greenland which would have added a lot to this and this gentlemen may have discussed it.

[@21LAZgoo]

@@AggressiveMediocrity1 hiawatha crater has now been dated to 58 million years ago, although there are still sites in north america that could possible impact sites

[@AggressiveMediocrity1]

@Z2B1RDIUS the potential connection was so intriguing.. back to the drawing board.

[@21LAZgoo]

@@AggressiveMediocrity1 true, although there are still possible impact sites in North America like lac st jean and lake nipogon that show evidence of catastrophic meltwater outflow and some other possible sites, because the main impacts were on ice they wouldn’t look like normal impact craters

[@MH-ms1dg]

15:55 it's now at least 20k i think

[@astick5249]

I mostly want the giant ground sloths back.

[@jointcerulean3350]

The ground sloths last strong hold was on Caribbean islands and became extinct due to humans some 6,000 years ago in the Holocene. Tho they weren’t as large as the ones on the mainland, still very much impressive and unfortunate that they did not survive to the present . And it would be great to bring them back, as well as extinct meiolania turtle and land crocs of the South Pacific.

[@ABC-yt1nq]

I just tried to wipe your avatar off of my screen. Well done!

[@21LAZgoo]

@@jointcerulean3350 who knows if there is evidence of ground sloths 6000 years ago on the mainland too, because it was thought that mammoths on the mainland continents all died out 10,000 years ago and only st paul and wrangel island mammoths lived longer, but now there is evidence in the yukon and in northern mainland siberia that mammoths survived in those places until 5000 and 3900 years ago, places were humans were already at for tens of thousands of years

[@alphalunamare]

9:08 It is rather odd that the Ice did not cover the Temperate zones in the Southern hemisphere to the extent that it did in the North. Clearly something is amiss with this image or of the understanding that it represents.

[@delishme2]

It does, go back and look, but there aren't any continents or land masses that close to it....

[@psycotria]

The Southern Ocean is a poor substrate for ice sheets, which brought the cold out of the north. Even today, the Southern Hemisphere is warmer, with the (getting colder) cold being trapped in Antarctica.

[@williewonka6694]

Land gets much colder than water and ocean currents distribute warm water to the higher latitudes. Glacial ice sheets largely occur in the northern hemisphere.

[@alphalunamare]

@@williewonka6694 That makes sense. Perhaps if tectonics had been different and more land be in the south then such would be otherwise. You cracked it! 🙂

[@williewonka6694]

@@alphalunamare Not me, just read about more glaciation on the land in the northern hemisphere and unimpeded circulation of southern seas around Anarctica.

[@erich930]

So, if the definition of mega fauna is an animal that is over 100 lbs, and if a fully grown human is well over 100 lbs, therefore humans are mega fauna, and so are deer and horses and elk and moose and bear, etc...

[@PlatformNo14]

Yes they are.

[@andrewbourn5269]

120 meters. 394 feet ! A touch more than 300 feet

[@thomasaurelius7134]

That's easy, they used everything so there isn't much left of any of the bodies if any. Maybe the spare random kill that couldn't be put to use properly.

[@baconator953]

Exactly

[@nmarbletoe8210]

how does one use a five foot long leg bone?

[@dirtbikerman1000]

Look at the bone yard in Alaska

[@morrgash]

So long story short is that we still don't know.....

[@tothetruthandbeyond4510]

Morry it was an asteroid.

[@tothetruthandbeyond4510]

Morry they just have to find the impact site. They've got and uncovered 5% of Gobekli Tepe. They just have to uncover the rest.

[@darkpandalord3844]

@@tothetruthandbeyond4510 if it was an asteroid the world currently would be a drastically different place though.

[@vanglhun8550]

@@darkpandalord3844 like it or not there's evidence of the asteriod impact

[@baconator953]

@@tothetruthandbeyond4510 uhm You do realize how massive our world is, right? Why did only big animals die and not smaller ones?

[@geofflewis8599]

it's not hard to understand, megafauna need lots of forage, as a result of a 'nuclear winter' brought about by the impact, the greenery disappeared and they starved, probably in months.. .

[@nmarbletoe8210]

"supply chain issues" as we would say today

[@Purplestickypill]

Obviously history and geology is showing us that what ever major disaster happened it missed most of Africa

[@21LAZgoo]

the younger dryas caused a giant buffalo, a large zebra and a very large wildebeest to go extinct in africa, although yes compared to the rest of the world africa barely lost any megafauna

[@yossarianmnichols9641]

Don't think we would be eating a 30ft lizard, we would be running from it.

[@useodyseeorbitchute9450]

For killing a dragon one gets princess and half of the kingdom. In practice for such megafauna it was food for whole clan until meat got bad and having let's say an increased mating potential for dude who managed to take down such beast. Clearly worth it.

[@glenncordova4027]

Just kill off all their food. 30 foot lizards gotta eat.

[@LordDirus007]

Graham Hancock was right

[@oobrocks]

Overkill is the only solution. The idea of "where's the bodie," is a stupid pt. They died somehow so "where's the bodies," no matter how they died

[@21LAZgoo]

how, humans coexisted with the megafauna for hundreds of thousands of years in eurasia and in north america tens of thousands of years, and then they all of a sudden collapse when these huge and quick climate changes take place

[@oobrocks]

They didn't

[@21LAZgoo]

@@oobrocks there have been human remains found in eurasia in a greek cave where the back part of a human skull was found that dates to around 210,000 years, and also part of a human jaw with some teeth found in israel that dates to around 177,000 to 194,000 years, and the earliest evidence so far of people in the north america is 24000 years possibly even older as new evidence is always coming out. So like i said, humans have been coexisting with the megafauna in eurasia for around 100,000-200,000 years, and humans in north america have been coexisting with the megafauna for at least 10,000 years if not older as new finds are always coming out

[@keithparker7732]

it there was no evaporation then where did the ice come from

[@jessfulbright9015]

First, humans have been in North America at least 23,000 years (google footprints at White Sands, NM), and probably much longer than that. Second, if humans had hunted any species to extinction, it would have been a species of turtles. Third, there is a huge difference between an Ice Age and a glacial period.

[@miquelescribanoivars5049]

Mainland giant tortoise are actually among the FIRST megafauna to become extinct as humans dispersed. The retraction of the range of Megatestudo atlas is a very close match to the expansion of Homo erectus out of Africa, and endemic mainland giant Meiolania and Giant American tortoise are also among the victims of the megafauna extinction. Only the Aldabra and Galapagos species survived because those island were never settled permanently by humans until recent historic times. And for the record, yes tortoise are slow and take a lot of time to mature, but they also have a whole lot more babies than any large mammals, so they can bounce back much quicker if hunting pressure stops.

[@imafkingbeastandrewtateise9563]

Megalania was definitely not 30 feet long lol

[@vesuvius115]

I think it was a mixture of things. A changing climate, humans, and a possible impact. We have caused extinctions before such as Thylacine and Kauai O' O' and us introducing wolves to North America could be one thing that aided in their extermination. A sudden climate change could of been sparked by a possible impact, its happened before. I don't think humans were responsible for EVERYTHING, but a large group of us and a group of wolves working together like back then could definitely been enough to do it. Instead of charging are prey down like tigers as well. We use to basically run the animal down to the point it over heated, Everytime the animal saw humans, it kept moving, but these animals couldn't sweat like us, so became exhausted. When it was exhausted enough, we went in for the kill. I think killing the herbivorous megafauna, aided in the downfall of carnivores that ate these megafauna along with the changing climate.

[@21LAZgoo]

humans were in north america at least 24,000 years ago. there was a 250,000 year old mastodon pelvis that had a mastodon carved into it along with tools found in a 250,000 year old stratum layer in mexico, even though this evidence is very solid i dont know if mainstream will ever accept it. it makes no sense that the 130,000 year old cerruti site is much wider known, when the evidence it has isnt as strong and also the date is nearly twice less than that of hueyatlaco. oh well i gues

[@speedracer2008]

Extinctions, in general, can’t be attributed to one cause. It’s often multiple causes. The extinction of the dinosaurs, for example. Yes, the impact of the asteroid into the Gulf of Mexico wiped out many dinosaurs at the beginning, but many survived the initial impact. The debris of the impact was shoved into the atmosphere and blocked out the sun. This prevented plants from using photosynthesis and eventually left the herbivores with no food. The carnivores had a banquet, but, then, they died with no more food to sustain them.

[@taboovsknowledge1603]

Before the cataclysm, it would have been a really cool place/time to visit. The giant sloth, wonder if they could be, over time, allow you to pet it? I still would go heavily armed and with a high tech sensor system for big cats & bears!

[@Dman9fp]

The world still is a pretty neat place, just have to look harder and use your head I think. But don't get too attached of course as I've learned lately lol, nowhere and no species is quite safe from modern corruption of man

[@taboovsknowledge1603]

@@Dman9fp The corruption is beyond 1984

[@Dman9fp]

@@taboovsknowledge1603 Oh yeah, only a matter of time before they remove KZbin comments entirely (many channels have the algorithm set to auto remove "controversial" comments) if they got rid of KZbin downvotes... But I didn't realize that, one KZbinr brought it up and makes more sense than not

[@Epsilonsama]

Not really. Most of the planet was actually pretty inhospitable with huge Ice Sheets covering the North, Tundra all the way down into the Mediterranean and Asia and long Deserts and little folliage. In between you had the big plains where the Megafauna lived which where big because for Mammals Size means better resistance to Cold.

[@erikhendrickson59]

Would truly be a sight to behold these MASSIVE creatures! It's difficult to imagine, but the Aboriginal people would've hunted 6,000 pound descendants of the modern wombat -- with simple flint-tip spears! Our ancestors were truly incredible!

[@billquigley6556]

Yep.

[@21LAZgoo]

yeah man plus those sabertooth chonks which weighed twice as much as lions

[@asiseeit2041]

Sorry man, we got hit by a big comet. And it jacked the whole world. To think man hunted all these species to extinction is just crass

[@Buckshot9796]

Nature created a hyper- predator when human and wolves teamed up. Together we both stood a much greater chance of having something to eat at the end of the day than we did alone.they Anyone who has hunted with dogs understands how deadly effective the human /wolf partnership is.

[@CandideSchmyles]

170+ peer reviewed papers now supporting the impact hypothesis in spite of the tenured ivy league opposition to real progress.

[@21LAZgoo]

yessirrrrrr YDIH cannot be denied

[@nmarbletoe8210]

I'm guessing a lot of those are from Ivy league schools, but I agree with the gist. "Ivy covered professors in Ivy covered halls..." But actually Harvard has free thinkers like Avi Loeb, and they can't be fired, so they can say what they want.

[@justmenotyou3151]

Anthony zamora has videos about an impact on the ice sheet around the Great lakes, resulting in secondary ice impacts forming the Carolina bays and Is nebraska rainwater basin. The North American megafana would have been Pulverized. Makes a lot of sense.

[@joecaner]

I'm a fan of Over Grill. Please pass the BBQ sauce.

[@FrontierLegacy]

He never mentioned disease.

[@miquelescribanoivars5049]

... Which is nearly impossible to test on extinct fauna. For what it's worth it's been attempted on extinct Megafauna from areas that are better for the preservation of DNA and so far linking diseases with extinction of megafauna has proven inconclusive while there seems to be a direct link between extinction and climate changes and human intervention.

[@FrontierLegacy]

@@miquelescribanoivars5049 True but if we look at invasive species and the introduced diseases that come with them. The die off rates of populations that are not resistant to those diseases can, if spread quickly enough lead to a decline in breeding adults that lead to extinction. This hypothesis has been purposed for the extinction of the dinosaurs so why would it not be plausible for the extinction for the megafauna?

[@miquelescribanoivars5049]

@@FrontierLegacy One has to consider that disease are likely to have a much more drastic effect in population swith a small range and low genetic diversity and both climate change and human intervention can easily be the cause behind those risk factors.

[@FrontierLegacy]

@@miquelescribanoivars5049 If the species did not migrate. Taking a look at what species went extinct, many of them, given their surviving relatives, must have migrated over large distances. Therefore spreading disease and devastating the populations. Now, this is simply a hypothesis. I never said I subscribed to it just that it is plausible. As the speaker said, a combination of these, including spread of disease, could be the explanation of extinction.

[@miquelescribanoivars5049]

​@@FrontierLegacy Migration may help to spread disease but it's effects on genetic diversity far outweight those caused by disease. Now, if a migratory species can no longer migrate due to changes in the enviornment/sea level/predator pressure. Now THAT'S when they are screwed. Just look a reindeer and saigas.

[@zakariwalker7477]

If we only got into the Americas 18,000 years ago, then how do you explain all of the things in the Americas like megalithic stuff and cave paintings

[@glenncordova4027]

There was a 30 foot long lizard, not a dinosaur. That is bigger than the biggest crocodile. Sorry, not sorry, I missed that.

[@benquinney2]

Mega mammals

[@BasePuma4007]

Those god damn egg head apes with their pointy sticks and clever tricks up to no good like always.

[@yossarianmnichols9641]

so elephants and hippos can survive human hunters but mammoths and short face cave bears cannot.

[@oliverdouglas9912]

It explains this in the video. Hippos and elephants live in africa, where humans are native. While short faced bears and mammoths lived in europe and america, where humans were invasive

[@raine5508]

@@oliverdouglas9912 I disagree

[@21LAZgoo]

@@oliverdouglas9912 yet humans coexisted with the megafauna in north america for at least 10,000 years, possibly even longer as new evidence is always coming out

[@BMLocal374]

Watch Randall Carlson and Graham Hancock. They’re the only ones who have a clue

[@twonumber22]

Hancock is a book pusher. Among many others, his ridiculous claim of ancient sites in India as being a depiction of Draco is outrageous.

[@Bix12]

Right you are, David. I'm watching this to find out A) if he even gets it right B) he gives credit where credit is due. Isn't it great to see all these knuckle draggers who have been slamming Graham and/or Randall all these years getting their asses handed to them?! I think it is sweet justice.

[@twonumber22]

@@Bix12 lol

[@tothetruthandbeyond4510]

William L. Yeah it'll be great once they find an impact site. and Slamz Dunk mate you don't know what you're talking about he's not 100% saying Angor Wat is the Draco constellation. He's saying at that time it has a resemblance to it.....

[@Bix12]

@@tothetruthandbeyond4510 i dont think there is an impact site per se considering it hit a 2 mile thick ice sheet...but they have found a burn off/charcoal layer with iridium and nanodiamonds - it will be accepted science soon....after the herd of indoctrinated elders is culled somewhat

[@sohowsoon6652]

let us stay away from crowd size

[@benquinney2]

TypeVIIc Type 95 Seawolf

[@monsterzero5843]

I have one question how did the earliest homo sabians get to Madagascar and those island in the Pacific Ocean

[@tothetruthandbeyond4510]

indowolf rex by boat they think.

[@DilbertMuc]

@Dirty Magic11 There are no aquatic apes. Apes can't swim and fear the water. A chimp in a zoo that falls into the water ravine drowns as his center of gravity being buyont is to the front. His legs are too short and too light. Monkeys have tails and can swim. Humans can swim. But no apes.

[@DilbertMuc]

@Dirty Magic11 Understood. But humans and apes separated some 2-3 million years in the lineage and evolved differently. Apes got nowhere, still living in trees and with limited capabilities and intelligence. However, check out Prof. Randall Carlsson's videos about human evolution and lost civilizations. Homo sapiens has been around unchanged for 200.000 years, but our known history goes back only 10.000 years to the last ice age. What happened in the remaining 190.000 years? Humanity accelerated from cave men to astronauts in only 10.000 years since hunting mamooths and it is hard to accept that they hunted mamooths for the previous 190.000 years. We were the same species and people. And there were warm periods in between the ice ages during the past 200.000 years. Thinking about that is highly compelling... ;)

[@DilbertMuc]

@Dirty Magic11 Human-like creature? On the contrary, I find it odd that we see a lot of variations of species everywhere, but not in humans. A cat, what is it? A tiger, lion, cheetah, housecat, puma...? It is all cats. There are many types of races in a species, but there is only one human race in the world (apart from 3 races/types of it: caucasian, mongoloid and negro). In Europe you are not even allowed to mention the word race, because it is racist and Europeans have to say "human in ethnic form". Anyway, they started to find various types of homo sapiens just like the Denisovans, Neanderthaler, Flores etc. Why shouldn't be there a much bigger variant from the past? But why are there no bones or fossils? I am not talking about the Yeti.

[@DilbertMuc]

@Dirty Magic11 You're right about fossils. But my question was somewhat different. In every culture there are ceremonial burials, which is just human nature. Even Neanderthals had burials and thus we could find fossilized/unfossilized bones. If there was a culture of "homo sapiens giganticus" with a higher civilization then there should have been cemeteries or burial sites. But there are none. In addition I wonder about past civilizations... why don't we find any hidden "advanced garbage" dumps like sealed nuclear dumps or signs of buried technology remains? So far there are none. I we'd dissappear, in 10.000 years nothing would be left of our civilization but future humanoids would find garbage dumps and underground caves with trash, nuclear remains, polluted underground water from oil fracturing and so on... giving hints about our capabilities.

[@GREGORYJHALL]

Over hunting hypothesis is ridiculous, not possible at all. Comet impact makes the most sense

[@justmenotyou3151]

Anthony zamora has videos about an impact on the ice sheet around the Great lakes, resulting in secondary ice impacts forming the Carolina bays and nebraska rainwater basin. The north american megafana would have been pulverized. Makes a lot of sense.

[@miquelescribanoivars5049]

Explain why the extinctions in Sahul happened earlier? Why the ones on islands adjacent to the mainland happened later? Why small species were not affected? Or how marine ecosystems were not affected at all, in spite of collapsing after the K/Pg impact?

[@juancuelloespinosa]

if earth is defined as a system of biological activity, then only a certain amount of biomass can exist on the surface at any one time, is there evidence of a human population explosion, consistent with the megafauna drop, in these areas?

[@mostlynew]

Science advances, one funeral at at time. ~. Max Planck

[@audrasenig7368]

Bible thumper?

[@airmark02]

Because academic careers and tenured university positions depend on the status quo

[@towboattrash]

I’ve waited years and nobody has proven yet that species are not supposed to go extinct. All that has been proven apparently is, that when a species does go extinct, it’s humans fault.

[@RemoteViewr1]

Pure speculation. Spitballing. Fragmentary ideas.

[@kennethmikaelsson7990]

Tjeck the iridium...Randal Carlson has a god idé on wats up

[@MrRalphla54]

The crater in Greenland and Saginaw Bay and the Carolina bays all point to a meteor impact. This is backed up with debris from these impacts found around the world. This guy is so invested in the old science he cannot grasp or does not want to grasp what really occurred.

[@OMGAnotherday]

Atila Hunn - That’s not what I picked up. He did give cognisance to an impact.

[@baconator953]

Different species went extinct in different years, sometimes seperated by thousands or even millions of years. Australia is thousands of miles away. So is South America. Megafauna existed all over the world... Dung microbes only found in grass-eating animals and microscopic ash particles show there was a massive change in the ecosystems of the planet after humans arrived to different continents, burned forests down, and began farming. A recent mammoth trap was discovered in Mexico, with 14 mammoth remains in it. We've been destroying the world in large scale for millions of years. Only now we have machines.

[@matthewstorer8236]

@@baconator953 Boy are you spot on. I truly believe nature has a reset button. I also believe it about to be pressed.

[@21LAZgoo]

@@baconator953 mammoths went extinct in europe at the same time that they did in north america despite humans arriving and spreading in europe tens many tens of thousands of years before there are some studies that say that the huge warming 14800 caused and didnt cause a megafauna population collapse, one study that was based off spormellia which i think your talking about said the was a megafauna population collapse in north america 14800 years ago, another study says that megafauna populations increased from it

[@jaygosev3589]

In a nutshell, the comet that created the Hiawatha Crater under the Greenland Ice Sheet around 12,000 years ago wiped out the majority of mega-fauna. Man-made extinctions occurred on islands like Madagascar. There, saved you both time and money. You're welcome

[@justmenotyou3151]

Anthony zamora has videos about an impact on the ice sheet around the Great lakes, resulting in secondary ice impacts forming the Carolina bays and Is nebraska rainwater basin. The north american megafana would have been pulverized. Makes a lot of sense.

[@inertparticles]

isn't he Canadian?

[@squaredharbors5988]

yes

[@coyotehump8253]

Fire and flood

[@21LAZgoo]

yessir

[@hornthieves]

transcendent

[@billstream1974]

This guy doesnt understand that a hunter gathering society would not overkill its food source. There was a impactor which occured approximately 12800 years ago. Prior to this time the clovis culture was flourishing after that boundry they were gone. Its is believed by many there were multiple impacts on the North American and European Ice sheet.

[@jholt03]

Where’s the crater? Where’s the crater? Blah blah blah… People are confusing a comet with a meteorite. If a two mile wide high density meteorite composed mostly of solid iron and or other heavy solid metallic materials strikes the earth it’s pretty likely to penetrate the atmosphere and leave a crater. If the same size cosmic impact is a caused by a fragmented comet made mostly of frozen gases and ice, which would also be travelling much, much faster than a typical meteorite, and it happens to enter the earth’s atmosphere above a 2 mile thick ice sheet, could we expect it to leave the same characteristic crater as the much denser, much slower moving meteorite? Because of the different characteristics between a comet and a meteor, the answer is no. If the earth gets hit with a fragmented comet the majority of the energy would be released when the comet hits the atmosphere rather than the ground, especially if the comet comes in at a more oblique angle, which would likely be the case due to the highly elliptical orbit typical of most comets. Take an ice cube directly out of the freezer and drop it in room temperature water. The rapid temperature change will cause the ice cube to pop and fracture. Now imagine a comet traveling at a speed of many thousands of miles per hour with a core temperature in the range of -200 degrees Celsius. The heat generated from friction when it enters the atmosphere would cause an almost instantaneous detonation, releasing energy in the form of enormously devastating atmospheric shock waves. This kind of event would have been more than capable of causing the mega fauna extinction associated with the younger dryas without leaving a crater discernable today. Particularly if the explosion occurred over an ice sheet up to two miles thick. Anthony Zemora's work exploring the origin of the Carolina Bays made me a believer.

[@MAGAman-uy7wh]

The three "causes" do not explain Buffalo in North America. IF the three "causes" occurred simultaneously (or nearly), then that might have been enough. All three have merit but none are conclusive. The comment posted by Eric Vulgate also has merit, but would not explain locations of fossils found and would have less impact on the surviving mainland. The micro nova concept provided by Dirty Magic 11 is an interesting concept . I do not know how that could be verified in the fossil record. Plants that existed then as a food source for mega Fauna may have been impacted. Is there any evidence of plant extinction that coincides with these three main concepts? A three year continental drought would have been enough to cause these extinctions.

[@fooslinger]

He certainly is smug and dismissive of catastrophic events that would cause extinction of mega fauna.

[@ctmhcoloradotreasureminehu8385]

25:22 to 25:30 he hits the nail on the head.

[@brianjacob8728]

I think you have to put more credence in all of the megafauna of the americas going extinct AT THE SAME TIME. What you say about life histories is true, but not true in the same regards for all these different fauna, as they would be able to respond to climate change (sic, the climate is always changing) or supposed hunting pressures. Surely some of these fauna would have been able to respond more positively to the impacts of either of these scenarios. For instance, do you think humans were really hunting saber toothed cats for food to the same extent that they were safer, more easily gathered food sources? Of course not. Yet the big cats and bears went extinct along with the horses and the mammoths... That leaves you with the impact hypothesis, which, as happened with the dinosaurs, was much more indescriminant, and if you're talking about basically melting all of the ice cap at once, would wipe out these fauna regardless of more or less advantageous life histories, as well as explaining the reintroduction of another period of extreme cooling/ice age as all this freshwater going into the north atlantic would have killed the north atlantic oscillation. This alternative fits more of the data better and more comprehensively than the other two.

[@nmarbletoe8210]

Yes I also like the Impact / climate change idea. There's a paper out that says Europe cooled in one year around the time of the YD onset.

[@brianjacob8728]

@@nmarbletoe8210 Agree, but bear in mind, one year was probably as fine of a scale as they could measure. This cool down may well have been more rapid than that.

[@Heywoodthepeckerwood]

Yeah, I can see a band of men killing a short faced bear with spears...

[@MrBadjohn69]

So no real unbiased science shown in this video

[@robertcharpentier6852]

This video is a bit out of date since a Greenland meteor/asteroid/comet strike crater has been found under the ice sheet there, which occurred at exactly this same time as all the mega fauna disappeared. The force of that blast from the extra-terrestrial object was more than that of all the nuclear weapons currently present on earth today by several times. It is estimated by current data that most of the human population in North America was wiped out by the blast as well as all the mega fauna. Additionally the blast was so great in scale that it also killed off the mega fauna in Central and South America as well as Europe and Asia. It had an incredible effect on the climate and probably caused an ice age that lasted for at least several hundred years after destroying entire habitats across the globe. We humans today are just one meteor/comet/asteroid strike away from extinction. Bet on it! StocktonRob

[@tenkdkme]

All of what you just said is unproofen speculation. I crater could be from as early as 3m years ago and most definitly didnt not impact the climat in south america since its just 31km wide so a lot smaller than other craters that are responsible for extincions.

[@bkjeong4302]

The megafauna did NOT all disappear at once like you claim. It disappeared at different times in different places, and only one of these times actually matches the supposed impact. The impact, for example, couldn’t possibly have killed off Australian megafauna, because they were already extinct at that point. Nor could it have killed off Madagascar’s megafauna, which lasted into historical times.

[@21LAZgoo]

@@bkjeong4302 your right, first there was a big sudden population decline at 14800 years ago because of the massive warming spike from the bolling allerod, and then the younger dryas came which wiped out the clovis people and decimated that already low population of megafauna even more, and then the last of them died out at 11600 years ago which is another massive warming spike

[@bkjeong4302]

@@21LAZgoo Except that Australia megafauna died out 40,000 years ago, before any of that. Also, the Younger Dryas was not some one-off cataclysm. We have evidence that the same sort of sudden cooling event happened in the interglacial before this one (there were actually many warm periods-the “ice age” was not continuous!)

[@21LAZgoo]

@@bkjeong4302 youre right i forgot to be specific about that, the australian megafauna did collapse around 42000 to 40000 years ago which is 25000 years after humans arrived there, and as for what you said after that, changes like that did happen before and they did coincide with fauna population declines, although the amount of them happening in a short amount of time and the intensity of them was probably not as much as the 3 big changes at the end of the ice age during those other times times to kill off every single one of the megafauna however i think the 3 big changes at the end of minused the population enough for them to all go extinct as they collapse right at those boundries

[@scorpiovenator_4736]

Who new intelligence would be so bad for everything else

[@Bootrosgali]

OVERGRILL ! OVERGRILL ! OVERGRILL ! Just think of the movie that will come out of it!!!

[@al20o33]

So sad, so true. So many more extinctions have happened since this video. Humans will never learn. The planet and all its ecosystems will not be safe until we are long gone.

[@jessfulbright9015]

Start @11:54 end @12:08 "Another aspect of this is that there was more than one ice age, in fact there were twenty-two, that we know of, advances and retreats of the ice in the last 2.6 million years..." WTF? Why would you choose that wording? There have been five ice ages in the last 2.6 billion years, they are well documented and named. We currently live in the Late Cenozoic Ice Age, which began 34 million years ago. The last 2.6 million years have been the coldest of the current ice age, this period is called the Quaternary Glaciation and coincides nicely with the Pleistocene Epoch. There were many advances and retreats of the ice in the last 2.6 million years, these are called glacial periods and interglacial periods, not ice ages. By about 20,000 years ago the planet had reached its coldest point in over 400 million years, then something drastic happened. The Quaternary Glaciation came to an end and very abrupt global warming took place, it was interrupted by the Younger Dryas event, but 11,700 years ago rapid warming began again and by 10,000 years ago the earth had warmed by about 16 degrees centigrade. For the last 10,000 years the earth's temperature has remained amazingly steady, not varying more than a couple of degrees either way. This doesn't mean the Late Cenozoic Ice Age has ended, we are simply living in an extremely stable interglacial period of that ice age that we have named the Holocene Epoch.

[@Appleblade]

Hopefully we can put enough CO2 back in the atmosphere and keep the planet warm and green. ;) Puzzled why Mr. MacPhee left out infectious diseases.

[@tomfitzgerald8150]

BECAUSE ANIMALS DONT LIVE IN CITIES UNLESS WE MAKE THEM!!!

[@user-ff4jl5ic9n]

I watched til 1:48 seconds. So interesting how the megafauna you showed, the sloth etc, still exist. Just diminished in size. I know from Randall Carlson that about 120 survived and 120 disappeared. Doesn't it make more sense that they did indeed not disappear, but just morphed, and that it was the earth that radically changed in a cataclysm. A cataclysm that every cultures have stories of. The telephone game would tell us all of their stories differently after thousands of years, possibly 12k year. i don't really do dates, but the evidence tells me, and there is so much more, that it was some time before a massive cataclysm that few survived. How few, who is to say at this point. Clearly the bibles' versions are twisted and distorted, but with the Gilgamesh, and the indus valley version we have some idea an arc of some sort was involved, the moon, a ship, a series of ships, high mountains, caves underground, we have many varying stories, no one can say for sure, yet It will be interesting to see what Ai has to say about it.

[@danchkovckoe]

+

[@johnstojanowski8126]

The cause of the extinction of the Pleistocene Megafauna, as stated by Ross MacPhee is still being debated. I believe my theory, ‘The Gravity Theory of Mass Extinction’ (GTME) is able to resolve the cause of the extinctions. GTME posits that when large mass on the surface of the Earth moves to high latitude one or more of the Earth’s core elements (Inner core, Outer core and densest part of the lower mantle) moves off-center. This results in a gravitational gradient around the globe, i.e., surface gravity lowers in one longitudinal region and a corresponding increase antipodal to the lower surface gravity region. The guiding scientific principal that governs this is the Law of Conservation of Angular Momentum. The start of the recent Ice Age occurred about 2.4 mya. Large surface mass (in the form of ocean water) was transferred to high latitude forming polar ice caps. As stated, this caused one or more of the core elements to move off-center lowering the surface gravity in one longitudinal region. That region was determined by the longitudinal distribution of polar ice/glaciers relative to the Earth’s axis. That region was not permanently fixed. As the polar ice distribution changed, the region with the lowest surface gravity changed. This is why megafauna developed in different regions at different times. It is also the region why megafauna extinctions were not synchronous worldwide. The Australian megafauna extinctions occurred about 50,000 to 40,000 years ago while the Western hemisphere extinctions occurred 20,000 to 10,000 years ago. It is possible that the appearance of Homo sapiens during the decline of megafauna in different regions at different times occurred because the increasing surface gravity, to near current value, allowed them to function in a manner that they were unable to do in a much lower surface gravity environment. Because the GTME posits that the Neanderthals gradually developed in a low surface gravity environment, which their body plan implies, their extinction during the same period of extinction of Eurasian megafauna is explainable; they were human megafauna. They didn’t become extinct from competition with Homo sapiens. It also explains why they seemed to have survived longest near the western coast of Europe, indicating the lowest surface gravity region was moving from east to west due to the changing distribution of polar ice at that time. This gravitational phenomenon is explained in two of my books: The Gravity Theory of Mass Extinction Ice Age Extinctions, A New Theory

[@rvaneman]

Lot of things said are already proven otherwise. people come to America 18.000 year back is so many times proven a wrong assumption. And many more things said are just mainstream old and wrong assumptions.

[@Sal.Manila]

Personally, I think that a global disease could’ve occurred. If bacterial/viral plagues became widespread, it’s possible that they may have had a great impact on extinctions. With a decline in population by disease, weakened megafauna could’ve been wiped out more easily by hunting.

[@KR-tu1kh]

The overkill theory was a great place to start. Kind of like trying to figure out how to drive a car by sitting in the trunk first. Move on. The theory doesn't hold water no matter how many patches you put on it.

[@ctmhcoloradotreasureminehu8385]

@5:35 hard to take someone serious when they do not know the difference between an ice age and a glaciation period within an ice age.

[@TheNoldaz]

@@mrervinnemeth We are in an intermediary between two glaciations of the ice age were in since 2 millions years

[@MarvinMonroe]

@@TheNoldaz yeah always kinda annoys me when I hear "the last ice age" when theyhe mean the glaciation that started to end 12k years ago

[@drhominidae]

We definitely know more about the Impact Hypothesis than we do about the Human Hunting Hypothesis (a couple of examples of marks on bones) or the Climate Change Hypothesis (assumed causation). The only thing that keeps people from saying so seems to be a reluctance to accept it or at least to investigate it honestly. There is overwhelming evidence for it. The "Black Mat" is not just in North America, but found across the Northern Hemisphere which appears to be a purposeful admission on the speaker's part. You may not agree with the hypothesis, but at least be honest about the data that is available. Making general statements and omissions just makes a person look petty, manipulative, and self-serving.

[@nmarbletoe8210]

I think many people have read the paper trashing the impact hypothesis and not the rebuttal, or the GISP ice core paper from 2013. Ice core dates the impact within 5 years, ~12,895 BP

[@justmenotyou3151]

Anthony zamora has videos about an impact on the ice sheet around the Great Lakes, resulting in secondary ice impacts forming the Carolina bays and Is nebraska rainwater basin. The north american megafuna would have been pulverized. Makes a lot of sense.

[@johanbtheman]

Honestly not sure how you made the connection with humans and extinction, it's too far a part from when humans arrived and other species got extinct.

[@iggytull624]

Nothing new here but I'll say it again. All of the planets deserts lie on the Tropic of Cancer and the Tropic of Capricorn. So all things being equal, Occam's razor would suggest climate change would have been a massive factor.

[@robinhawkins335]

The eastern Oregon desert is not near those lattitudes also Occam's razor is a somewhat feeble tool.

[@imjennasidel6703]

I really think the extinction being caused by humans is stupid explain this to me if where we go we “overkill” everything how didn’t we ”overkill” everything in our continent of origin Africa. I think there’s a big flaw in this theory.

[@imjennasidel6703]

And why would humans with spears be hunting terror birds? They went extinct to I think this makes no sense.

[@glenncordova4027]

@@imjennasidel6703 if you kill off all the animals that terror birds eat those birds are out of luck.☠️

[@imjennasidel6703]

@@glenncordova4027 what about the Giant armadillos

[@imjennasidel6703]

@@glenncordova4027 and the giant beavers the 4 species of mammoths

[@21LAZgoo]

@@imjennasidel6703 and bird species that also went extinct

[@chir0pter]

This is a bad summary. For one, studies (e.g. Surovell and Waguespeck 2008) have modeled the sparse data we have, and shown that the number of known kill sites is not lower than expected, since all paleo finds are rare, and in fact shows a very heavy hunting pressure. Secondly, it makes no mention of the results of high-resolution proxy studies (e.g. Sporormiella), which show the bulk of the decline, at least in North America, predated both Clovis (specialized big-game hunters) and the Younger Dryas cold snap and associated impact theories. Finally, if you think that humans were merely a helping hand to climate in some cases as habitats shrunk, why then did animals disappear from the habitats that expanded or changed little, such as grasslands, temperate woodland, or tropical/subtropical forests? Clearly, in those cases, if not all, humans were necessary and sufficient.

[@21LAZgoo]

yeah, people coexisted with the megafauna for tens of thousands of yeats in north america and then after that the fauna populations suddenly started to collapse because of that massive warming spike 14800 years ago

[@chir0pter]

@@21LAZgoo " people coexisted with the megafauna for tens of thousands of yeats in north america" no they didn't. and there Bolling Alerud/Younger Dryas was more northern hemisphere and there were plenty of warmer habitats that expanded and southern hemisphere habitats relatively unaffected by that climate shift and they were emptied of megafauna too. also the vegetation didn't change until after the megafauna were gone (again sporormiella studies) which shows that it wasn't climate change altering habitat causing megaherbivores to die out. animals can move around.

[@21LAZgoo]

@@chir0pter bolling allerod was 14800 years ago, earliest evidence for people in the americas is 24000 years ago possibly even older as new evidence is always being found, so i guess you could say that people in north america coexisted with the megafauna for ten thousand years, instead of tens of thousands of years

[@chir0pter]

@@21LAZgoo The evidence for humans that far back is equivocal, scarce, and geographically limited. Sparse populations that may not have been big game hunters may have coexisted in some areas like the Pacific coast far back but it’s clear that Clovis was the end game, after people had driven megafauna to low abundance over time. After megafauna gone, you had ecological release of novel plant communities, showing the role of the megafauna in structuring flora; if it was climate first, then changing plant communities would have occurred before megafauna extinction. Read the sporormiella papers.

[@21LAZgoo]

@@chir0pter I think i saw those, there were some people who said that those sporormiella studies werent totally reliable because the doodoo could also be from modern animals or something like that i forgot, i read it off somewhere but i cant find where i read it off from rn so i guess i wont count that, but what i will say is that the clovis people, they spread rapidly throughout north america starting 13,400 years ago until they get wiped out and the megafauna gets decimated at the same time at the younger dryas onset 12900 years ago, that study you are showing (and im not saying its reliable i think thats true, as that huge meltwater spike did cause some faunal population collapses) shows that 2% of the megafauna population was still alive right after 13700 years, and what that means is that by the time this collapse in megafauna population has occurred, the clovis people arent even in north america yet. also, there was some site that showed that the south american fauna coexisted with humans for thousands of years but then when that meltwater spike came 14800 years ago the fauna populations collapsed, bruh i used to be able to see it but now it wants a subscription, and there was a study released last year that showed that around 14000 years ago when the trees and shrubs expanded, the megafauna were still abundant, and then shortly after they had expanded was when the megafauna started to collapse also, theres evidence of human footprints that date between 21130 and 22800 years ago, so the evidence for humans at that time is unequivocal

[@nokiot9]

:: Paul Martin wants to know your location::

[@nokiot9]

Aw damn lol you got him 🤦‍♂️😂

[@nokiot9]

You can’t really talk about this without mentioning him.

[@21LAZgoo]

there were people in north america 24000 years ago possibly even older than that as new evidence is always coming up, and paul martin says that the clovis culture quickly spread throughout north america in a span of 13400 to 12900 years ago (which is true) and were the ones that killed off the megafauna, yet the megafauna population gets decimated with very few survivors and the clovis people get wiped out at the same time at the younger dryas onset

[@fabzlab1980]

we dropped nuclear bombs ....overkill and grill at same time

[@21LAZgoo]

could be, if it has taken us around 700 years to be able to make a bomb that is 4 times as powerful as tunguska, then who knows what humans hundreds of thousands of years could do

[@RandallDibble]

The overkill idea is largely promoted by those who don't hunt. Those who hunt generally are faced with the reality of hunting and don't sign on to the idea. GO hunting with a shrape stick in order to feed yourself and you will question the theory of over Kill.

[@nmarbletoe8210]

Agree. But, remember that we are used to living with laws that prevent the most effective mans of harvesting animals, such as trapping, baiting, poison, etc. Hunting should probably be called harvesting. I bet 90% of the meat was not "shot" but trapped or tricked.