How Did Pleistocene Megafauna Go Extinct? GEO GIRL

[@GEOGIRL]

I hope you enjoyed the video! You can support the Dino Survival Kickstarter here: www.kickstarter.com/projects/davidgamemaker/dino-survival? And you can check out the Dino Survival website here: dino-survival.com/products/dino-survival-card-game?

[@babotond]

those are danish words, so the r in Allerød is a deep raspy throat sound, and ø is like _fur._

[@kerriemckinstry-jett8625]

That looks like a cool game! It scratches two itches: games & dinosaurs. I've been looking for a more adult version of a dinosaur game for awhile... the current ones are more like "help your dino get off the island before the volcano blows, ages 4-6".

[@drewharrison6433]

Dire Wolf is also a Grateful Dead song and a monster in D&D.

[@bkjeong4302]

I have to say there are some serious issues with the video in terms of accuracy, and it’s incredibly frustrating because you’ve ended up spreading some common but harmful misconceptions around. To boot: - “competition with modern animals” flat-out doesn’t work as a cause of extinction for the megafauna, because the “modern” animals were NOT newly evolved competitors. Most living animals had already evolved by the Late Pleistocene, BEFORE any of these extinctions happened. In other words, extinct Pleistocene megafauna couldn’t have been outcompeted by modern animals because they WERE among said modern animals (evolutionarily and ecologically). - you’re trying to describe all Pleistocene megafauna as being cold-adapted, when a lot of them weren’t (basically everything that was reliant on forested settings like Smilodon or mastodons, most ground sloths, etc), and still other basically didn’t care (Arctodus, etc). This has MASSIVE implications for why they went extinct, since any sort of climate-driven extinction would have only harmed one set of megafauna and benefitted the other set more suited for the new conditions. - The Younger Dryas was NOT a one-off climate cataclysm. Similar climatic fluctuations happened during the early stages of all previous interglacials. And yes, previous interglacials existed throughout the Late Pleistocene-the “ice age” was NOT a continuous glacial period. Since the megafauna survived all those changes (and tying into the above, each change only harmed one set of megafaunal species while benefitting the other set due to different climate and habitat requirements), that further reduces the role climate could have played in megafaunal extinctions. To sum it all up-the only possible cause that actually fits the overall data is some sort of human impact, whether it be hunting, spread of diseases or habitat destruction.

[@Akio-fy7ep]

@@bkjeong4302 It is completely implausible that humans drove 30+ continenal genera to extinction. Humans have driven island species to extinction, but never managed it on a continental scale. Humans were in North America for many thousands of years before the event. I am surprised and disappointed to find anybody still promoting that old saw. The only animals for which a human cause can be plausible is the mammoth, as we know happened much later when Inuit reached Wrangel Island. What we know happened at the right time was the comet strike, coincident with the start of the Younger Dryas. Nobody knows what was its role in triggering the YD, if any, and might not for a long time. But that it caused continent-wide wildfires is no longer in question, supported by spikes in platinum concentration and ammonia from dozens of sites in North America and in Greenland and Antarctic ice cores. Failing to mention the comet strike is a big disappointment, that could be fixed in a subsequent video. See particularly papers by Wendy Wolbach and James Kennet. Martin Sweatman wrote a good survey article in (I think) 2019.

[@kerriemckinstry-jett8625]

Pleistocene megafauna need to be recreated as plushies. Everyone wants to cuddle with a wooly rhino plushie, right? And how adorable would a glyptodon plushie be?

[@Smilo-the-Sabertooth]

Definitely one of my favorite subjects by far that you’ve covered. Something that I also know a great deal about as well, especially when it comes to the bizarre and magnificent Megafauna.

[@GEOGIRL]

Smilo! I was hoping you'd see this one, I thought of you when I was going over the Smilodon part! ;D

[@Smilo-the-Sabertooth]

@@GEOGIRL Yes of course, the best way to catch my attention!! So nice to know I crossed your mind during the Smilodon part. :D And don’t worry, I’ve still been watching all your other videos, even though I haven’t been commenting as often as I used to. ;)

[@Mrbfgray]

She's out of date on human occupation of Americas which is now confirmed at least 27k yrs ago, possibly much older. (see White Sands footprints latest dating) So the human linked extinction hypothesis is much weaker today.

[@donaldbrizzolara7720]

Rachel: The Rancho La Brea tar pit fauna holds a veritable treasure trove of data on Pleistocene megafauna and pollen. I know several west coast universities are actively pursuing the extinction problem based on this data. When I was a student at UC Berkeley I had access to the then department of paleontology’s massive vertebrate mammal collection. It was extraordinary and a sight to behold.

[@DinoSurvivalOfficial]

Hi Rachel, Thank you so much for featuring my game and your feedback! I hope your viewers enjoy it and that I get to make expansions for it.

[@kerriemckinstry-jett8625]

Hi! I backed it. I've been looking for dinosaur games which aren't geared for small children or have some kind of silly theme (like a dino version of a war game or something) but one which is made for people who think dinosaurs are cool & want to learn more. Fingers crossed, you get to make the expansions. 🦖🦕

[@charlesmartin1121]

Dinosaurs have always been my first and foremost interest, but the Pleistocene Megafauna is right behind them in total badassery.

[@PrincepratapsinghRawat-cw5em]

Same here

[@jointcerulean3350]

Awesome! Also Australia has some really unique megafauna such as giant ziphodont terrestrial land dwelling crocodiles that could gallop, and armored horned land turtles, and other cool species as well.

[@glenwarrengeology]

Sthenurus was an interesting genera.

[@SRWGodzilla4787]

Also the komodo dragon on steroids and the Giant wombat

[@glenwarrengeology]

@@SRWGodzilla4787 Diprotodon and Megalania.

[@josejaviergd9993]

Glad to have you back, greetings from Mexico

[@hdufort]

The megafauna went extinct but some of the fruits that depended on them for survival and seed dispersal (such as mango and avocado) survived thanks to us hungry/crafty humans.

[@mozismobile]

What about the giant wombats? There was also a giant platypus 5-15MYA but it had teeth so even weirder than the modern ones.

[@TheJake76]

20:10 human arrival has actually been pushed back quite a bit to 24,000 to 26,000 years ago and that evidence was found all the way into New Mexico. So humans had coexisted with the North American mega fauna for 12 to 14,000 years before they began to experience the extiction event.

[@christophersmith8316]

Smilodon has such a specialized kill method for large prey I imagine they were more solo hunters rather than large prides.

[@cerealport2726]

Australian megafauna was not at large as in other places, but I am not sure I would have liked to meet a group of 800lb wombats if they were in a bad mood. Red Kangaroos and Cassowaries are classified as megafauna, and are still around today. Both very dangerous when annoyed.

[@miquelescribanoivars5049]

Large male Diprotodons were the size of a female asian elephant, would still rank in the top 5 of largest land animal if they survived (but mastodon, giant sloths and gomphotheres didn't)

[@cerealport2726]

@@miquelescribanoivars5049 perhaps they tasted quite nice when flame grilled...?!!

[@danwylie-sears1134]

As for the relatively large presence of dire wolves in fiction, my guess is that it came from the popularity of La Brea tar pits as a tourist destination. It's certainly much older than Game of Thrones.

[@supersleepygrumpybear]

Probably actually? Maybe..? It's a D&D thing- I remember fighting Dire Wolves in Baldur's Gate 2 back in 2000, but considering how many video games and movies were influenced by California (and Texas) geographies, including the La Brea Tar pit smack dab in the middle of downtown LA. Sure. I can imagine Gary Gary Gygax and Dave Arneson were imagining their war-fantasy game while they were lost in browsing California's tar pit-

[@j.f.fisher5318]

Also, wolves loom large as a fictional threat, but real wolves aren't nearly so dangerous. Dire wolves are a way to boost the danger of wolves to the level of threat that fiction presents. Also, the name is hype.

[@danwylie-sears1134]

@@j.f.fisher5318 Indeed.

[@andrewshear2927]

I found your channel a couple of years ago and I found it fun. Also I have to point out that you forgot the American Lion.

[@benmcreynolds8581]

Prehistoric megafauna and everything else that was around during that era is some of my favorite moments in all of earth's timeline. The amount of different types of animals is crazy! We all know the most popular but there are so many different species with in these different animal groups. For example there was so many different types of saber toothed cats, big cats, giant Mustalids, crazy kinds of marsupials, giant kamodo dragon type lizards, the list goes on and on. The biodiversity was so complex and impressive back then. It's a dream to imagine what those habitats and ecosystems must have been like.

[@georgefspicka5483]

Hi Geo-Girl 😊, this is my most favorite extinction-debate that I follow. I tend to favor the impact theory, but I'm open to all ideas. I've seen the two NOVA presentations plus a number of other papers, articles, and presentations. Not only does all this hint at what may be the cause, to me it shows some psychological insight as to how researchers think through what happened. I may have mentioned that back in January, the Natural History Society of Maryland acquired a Alaskan Mammoth, estimated to be some 40 million years old.

[@GEOGIRL]

I also find the impact theory so interesting! I watched the NOVA series on it too and have now read many papers (in prep for the YDIH video that will come week after next) and it is so back and forth depending on whose paper you read haha! I mean, I don't think we have a clear consensus yet, but it is certainly something I can't wait to see more future research on :D

[@FrancisFjordCupola]

Megatherium was always one of my favorites. Just because it's a cool name, heard it was a giant ground sloth later.

[@peteronyoutube612]

Rachel is back! I'm sure I'm not the only one who noticed you didn't post a video last week: we all deserve time-off, and I hope you enjoyed yours. Welcome back!

[@GEOGIRL]

Thank you so much! Yep, two weeks off actually! (sorry for the break, it was not intentional, I just overbooked myself on other projects haha) Hope you enjoy the video :D

[@hazardousmaterials1284]

Two weeks off! But who’s counting! 😊

[@urrywest]

@@GEOGIRL I almost exprienced a mega fauna extinction event, suffering from what I think was a generalized infection disorder supposedly reversed by broad specrum antibiotocs. It woundn't be the first time.... There are other theorists who think that the desese resistance of humans is not all that advanced as compared to crocidillians... To be sure I need to read the diognostic report now that I am feeling a bit stronger after two days.

[@josemariatrueba4568]

I also like her videos a lot. Her ability to communicate is great. Her speech is very clear, and I love her accent, too. The only thing that disturbs her videos is that she must fit the official narrative in order to get a good job at any university. I'm afraid that we must wait until she retires and she's free to talk her truth in order to hear the right conclusions on a lifetime, learning more and more as time goes by.

[@urrywest]

@@josemariatrueba4568 My impression is that things that have to do with eocnomics and politics and commersce [like medicine] twisted at the university and often become non arts where as basic scinece is pure art-science. Why is my imression wrong?

[@rebeccawinter472]

Thanks Rachel. Hope the paper writing went well! Looking forward to next video on the YD. Lots of silly theories bout that.

[@jasoncuculo7035]

Megafauna from around the world. Today there are North American Bison, there was a buffalo species as well as giant Bison species nearly 3 meters to the shoulder in the Pleistocene. Giant armadillos, and giant ground sloths. Giant deer in Europe (Megaceros) and in India a 4-ton tortoise that lived in the Decan Peninsula, Smilodon fatalis, but multiple other saber-tooth tiger and cat species. Many other giant species, 17-foot iguana in Equatorial West Africa, even giant beavers, a 1,500 pound (650 kg) giant Antigua Rat in the Caribbean and so forth.

[@joer4]

Hi, I really love your work and always enjoy your videos. One small critique of this video however is that you don't point out that you are focusing on the megafauna extinction that occurred in the Americas and, to a lesser extent, in Serbia which was connected to North America by the Bering Land Bridge. A similar megafauna extinction occurred 40,000 years ago in Australia, also coincidental with the arrival of humans on the continent. Interestingly, African megafauna survived into the present age, on the continent where humans evolved. The continuing human caused mass extinction event however may overwhelm these majestic creatures in time as well.

[@davidniemi6553]

The paradox of megafauna surviving longer in Africa may have something to do with them evolving along with early, middle, and modern humans, vs. having modern humans suddenly show up out of the blue.

[@ronaldbucchino1086]

Been watching a KZbinr who explores the southwest native american cliff dwelling sites -- we always thing about other hostile human tribes being predatory -- however maybe megafauna bears, wolves and cats should also be considered -- I am sure some archo-geologist have documented what animal bones are found in common with these ancient human dwellings' Maybe? Good job Doc!!!

[@ronaldbucchino1086]

kzbin.info/www/bejne/qpizqnlomqetrq8

[@esslar1]

Good point about how humans affect megafauna is more than just hunting. Humans cause many changes in environments that also can lead to extinction along with hunting.

[@TrivettTurner]

Yea, but nomadic hunter gatherers are the subset of humans *least* likely _&_ capable of affecting the environment in such a way.

[@esslar1]

@@TrivettTurner Forager-gatherers and their surroundings co-evolve. That takes time. When humans first came into N. America, they were, in a sense, an invasive species. So, they had an effect there that was far greater than in the places they'd already lived in for 10s of thousands of years.

[@TrivettTurner]

@@esslar1 Invasive species are one who's food consumption rate and reproduction rate are on a level that the new habitat can't sustain & isn't balanced out by predation. It takes 9 months to make a new human & stabbing at hairy elephants with sharp sticks sounds more like Darwin Award competition than it does a long term food acquisition strategy. Plus doing it while wearing clothes made from everything a sabertooth eats, all while not weighing as much as an SUV, being encased in bone armor, nor having teeth the size of howitzer shells. Really think about it for a bit.

[@NachtmahrNebenan]

Hey, I'm here! 👋 I'm 197 cm at 95 kg - Megafauna is here 😅

[@charlesmartin1121]

Your a funny large guy.

[@joecanales9631]

Howdy Doc. Thanks for your enjoyable video. Looking forward to seeing your insights into the Younger Dryas, which sounds like it was more impactful than the Older Dryas. I think Dryas was an Arctic Tundra flowering plant.

[@rursus8354]

Some two-legged marauders? UPDATE: 'dryas' means tree in Greek.

[@JusNoBS420]

I find these megafauna especially interesting. New to your channel. Thanks

[@footfault1941]

"Mega" is probably because of downsized modern counterparts, but truly "Mega", tons way above, took place before KPg extinction. Super-Mega? Curious things are: 1) land animals underwent miniaturization, roughly speaking, 2) those giants are mainly composed of herbivorous members, while predators are way lighter, compared to the Mesozoic era, & 3) gigantism in mammals (although not presented here avian giants shared the same fate). Compare to extinction events in this site, this time around it looks as if less complex. Earlier videos demonstrated narratives ranging wide, series of geological setups etc. That may indicate this extinction event might be quite different, despite climate change, overall condition might be relatively calm without noticeable volcanic activities or receding coastlines etc. This video may need sequel! By the way, was the extinction featured here limited to landscape, no coinciding things happening in the ocean?

[@skipugh]

Thank you. You make this very easy to understand 😊. The charts are especially helpful. One of your earlier videos probably covered my question; but, how do we know what the temperatures and CO2 levels were millions of years ago ?

[@GEOGIRL]

There are various proxies (signatures in the rocks) we can use to reconstruct past T & CO2, I talk about this at length in the 'how we study earths past' video, here's the link if you want to check it out: kzbin.info/www/bejne/gGq3lpKpfL-SmZIsi=__PJeeHmpyJE06d7 ;)

[@ncpolley]

The Dire Wolf is a common fantasy staple, i believe it comes from Dungeons and Dragons. It may be based on the real thing.

[@nathanmiller5658]

Great vid GG. I hope Texas adopts the Glyptodon as the official state prehistoric critter.

[@wildmanofthenorth1598]

I believe I found a piece of armor from a giant armadillo Found it while rock hunting in Arkansas. I could share a picture of it if you are interested in taking a look. I like collecting what I believe are meteorites.

[@pikmin4743]

another great video, Doc! I'll make it easy for you to watch GoT..only watch the first season, and read the books (or don't yet, because the series is not complete) 🙂

[@whiskeytango9769]

Dire wolves, short faced bears, smilodon...if I was part of the group of humans that first wandered into the Americas, it surely would have been terrifying to see these predators who would have had no fear of humans whatsoever.

[@charlesmartin1121]

If you want to visualize what you are referring to checkout 'The Monsters We Met" or something like that. There is an encounter between a Shortfaced Bear and a paleoindian. It will give you nightmares.

[@urrywest]

I can't believe that annoyed humans couldn't have figured out how to destroy short faced bears, other solitary preditors and perhaps some pack preditors.

[@whiskeytango9769]

@@urrywest Maybe true, but in a world where any injury could be fatal, I suspect that humans would mostly avoid them unless they had no other choice.

[@urrywest]

@@whiskeytango9769 I figure we have preditors one with more skills and one with less skills... Teritorial, one would get the other the fuck out of there one way or another. Maybe they would come to an armists? Who knows? I can't imagine humans not being dominant.

[@whiskeytango9769]

@@urrywest Humans are clearly dominant, and also not stupid. Would you and a group of friends tackle a Grizzly if all you have were sharp sticks and no medical care available? I suspect that you would be rather cautious about such things. Now imagine a bear twice the size of a Grizzly and with no fear of humans at all. I suspect that taking on such animals was not the norm, even if it did happen occasionally. I suspect that the introduction of humans into the ecosystem caused extinctions more by upsetting the apple cart more than through direct hunting and extermination. We likely put enough pressure on the easier ones and their extinctions had ripple effects. So, while I am sure that there would have been some intrepid individuals who would want to take on Smilodon or the Giant Short Faced Bear, it was likely not a common thing, nor did it directly result in their extinction.

[@rursus8354]

Notoungulata means "southern hoofed animals". They're very distantly related to the Perissodactyls: horses and rhinos.

[@jasoncuculo7035]

Younger drys is the Genus and species of an artic flower that the sudden cold period from 12,900 years ago to 11,650 years ago (roughly).

[@josemariatrueba4568]

Temperature changes of 15 degrees Celsius, as shown in the graphs, in such a short time.... why? 12900 minus 11300 is only 1600 years or 16 centuries between temperature going suddenly up, to go down suddenly also, and back up again to enter the present warm period. Can you imagine such huge changes happening between the present and the 4th century after Jesus? The best thing that we can say is that we are very ignorant while pretending to have the right answer for any question.

[@AkasaurusRex]

Beautiful Palaeo Girl, well I’m in LOVE 😻😻😻 Great timing for this video ad I finally got to my city s big museum yesterday. It had most Cenozoic fossil displays with just a few but great Dino’s. But very nice ones a Mammoth, Mastodon, American Lion, Short face Bear, Smilidon, Camel. Hadn’t seen those before I LOVE American/Cave Lions! Got some great gift shop stuff too like Mammoth plushie lol And I’m 44 😸

[@michaeleisenberg7867]

Hi Rachel 🚵, I'm back on the elliptical watching 👀 you. Thank you very much for this very interesting video!

[@jasoncuculo7035]

Megalania prisca a 4,500-pound 25-foot monitor lizard that was the Pleistocene apex predator of Australia.

[@loganstrong9874]

Of note I just watched a vid about Saber tooth's fossil at the tar pits in California ,Saber tooth bones from the tar had some with terrible injuries that healed or still on going issue for the Cat .(One cat had a dislocated hip ,and terrible infection ,but the hip area was trying to heal ,the cat only died getting trapped in the tar pits .They wouldn't have being able to hunt unless they were in a group /pride .

[@socket_error1000]

I really think the best evidence that climate change had the most impact is the African megafauna that managed to survive alongside humans to this day. The big difference is that Africa did not experience the same dramatic climate change as the regions where megafauna went extinct. We also have the animals that survived and thrived in the vacuum after the other megafauna went extinct. Bison being a good example. They became the prime prey of the bloodthirsty human hunters and yet the bison population numbered 60 million just 150 years ago despite being hunted aggressively by the Native Americans throughout their history. It is in direct opposition to the idea that human predation caused the extinction event. I believe humans could have had an impact on species already on the brink, but I don't think they were any more to blame than any other predator.

[@charlesmartin1121]

WRONG.

[@georgegibson707]

No, mega fauna still existing in Africa where humans evolved is good evidence that humans caused extinctions in other continents where there weren't early human populations.

[@seanwelch007]

The two earlier geologic periods where the dryas flower was abundant in Europe are the Oldest Dryas (approx. 18,500-14,000 BP) and Older Dryas (~14,050-13,900 BP), respectively

[@PepsiMagt]

Great video doctor Phillips ❤

[@tfsheahan2265]

One thing I've never gotten about the human over-hunting caused extinctions, is the fact that horses and camels that crossed the Bering Straight going west into Asia where human already existed and would have hunted them thrived, and did not go extinct like North America. What would account for that?

[@j.f.fisher5318]

The usual theory is they contacted humans earlier in our technological development and had a chance to adapt to us before we reached an overwhelming level of hunting ability. Similarly, everything in Africa is highly adapted to be very difficult for humans to hunt. By contrast the fauna of the Americas didn't have that advantage and highly developed human hunters slaughtered everything that wasn't fast, dangerous, or both.

[@Madash023]

Great video, always love your stuff! You said sabre-toothed tigers are big cats, but I don't think that's true. Smilodon is the genus, correct? Big cats refers specifically to the genus Panthera, which is why cheetahs and pumas are not big cats. So I don't think sabre-tooths would fall under that clade either.

[@shadeen3604]

Great thanks dr geo girl excellent video

[@tsmspace]

all of these animal family names are so outrageous, being some crazy word, but in the 80's or something someone decided they wanted to use the word "dinosaur" as one of those names, and then somehow the definition for dinosaur that existed for over 100 years just "goes extict"?? BTW english doesn't work that way, ye-old english words can still be used and their ye-old meanings still apply. I mean except dinosaur somehow. Somehow dimetrodon just isn't a dinosaur anymore, even when all of these crazy animal familia names are literally just so that there is a unique word, and have nothing to do with spoken language. A bug is still a bug, even if it's a spider, and a chicken ... is not a dinosaur. It's a fun thought experiment, and it may work out that as a descendent they can be classified in the clade dinosauria (a different word, btw) meaning that a chicken can be called a dinosauria (a different word, btw) , but a dimetrodon , regardless of its status as a synapsid, is one of the original dinosaurs, was a dinosaur for over 100 years, and remains today, a dinosaur.

[@robbabcock_]

Great video! And any viewers that have not visited the Mammoth Site really should see it. 😎🔥🙌

[@GEOGIRL]

Yes! Both of them :D

[@supersleepygrumpybear]

Hey Rachel, I read all the comments (even the trolls), and the answer is Dungeons and Dragons. It's Dungeons and Dragons where Dire Wolves are most attributed in modern fantasy culture. There is Nordic mythology and Fenrir, also Lord of the Rings and Wargs. Although I don't know Game of Thrones, never watched the show or read the books, but I do love history and video games: I'd rather read about Wars of Roses and play Eldenring. I could also swear I fought thousands of Dire Wolves in some JRPG like Final Fantasy or Shining Force ¯\_(ツ)_/¯

[@JennieKermode]

The dire wolves in 'Game of Thrones' look like big wolves, whereas real dire wolves, iirc, were reddish in colour and had differently shaped heads. Four of those fictional dire wolves behave like dogs but two exhibit wolf-like behaviours.

[@Agentlemannevertells]

Danish person here, your pronunciation of Bølling-Allerød isn't that far off.

[@stevoplex]

Stomped by Gomphotheres! 😮 Oh! Oh no!

[@nicholasmaude6906]

I think that human predation played a role in the extinction of the Megafauna, Rachael, remember these very large animals needed large ranges to feed, they had long gestation times (The African elephant at 22 months is the longest) so reproduced slowly and took a long time to mature sexually. This means that the survival rate amongst Megafauna young only to drop a few percent (Due to human predation) for the populations to start collapsing.

[@qwertyuiopgarth]

It doesn't have to be much hunting. If the local population of 'Megafauna Species' can handle the loss of 100 individuals in an average year (natural causes, etc.) and humans move in and bring the death rate up to 101 or 102 that species is going to go locally extinct....although it might take a thousand years and never look like humans are hunting the species 'a lot'. (I would put cash on the Younger Dryas having multiple relevant causes.)

[@j.f.fisher5318]

I feel like hunting has to be part of it because there had been a lot of ups and downs in the climate during previous glacials. One of the ideas I've seen that hasn't been integrated into the question of extinction is humans possibly depending heavily on partially-digested plants from the guts of large herbivores in addition to their meat. If that's true and the herbivores started to starve due to the cooling, humans would have to hunt even more to get enough of the gut contents, killing them off even faster. I think it also helps explain why behaviorally modern humans were around from ca 70kya but didn't develop intensive agriculture until after the younger dryas. After that the walking bags of saurkraut had died off so we needed to grow our own.

[@grindsaur]

Your pronunciation of 'Bølling-Allerød' was actually fairly good :)

[@GeoffryGifari]

Shocking convergent evolution between Glyptodon and Ankylosaurus

[@posticusmaximus1739]

You should see Doedicurus

[@GeoffryGifari]

@@posticusmaximus1739 even more shocking

[@SRWGodzilla4787]

You should see Meiolania, this tortoise even got the Ankylosaur horns and tail club

[@GeoffryGifari]

Hmmm rapid cooling seems responsible for many of these extinctions... what about areas around the equator?

[@ddkapps]

You glossed over quite a bit there. For instance, the overhunting explanation is based entirely on a coincidence of timing, and only really makes sense in the context of Clovis First. Yet almost no one believes Clovis First anymore, as there is now ample evidence of human habitation well before the Clovis culture. Moreover, there is some concrete evidence of the impact theory, which hopefully you will address in the next video. Likewise with the volcanic hypothesis. At this point the field seems to be in flux, and sure there is some controversy as there always seems to be in academia, but IMO the old overhunting explanations don't really fit all that well with the latest evidence. Looking forward to the next video.

[@johnspence5689]

Maybe one day she will

[@boblarson7145]

The Clovis culture is defined by a specific hunting technology. As far as I know, the White Sands footprints have not yet been connected to any particular hunting methods. Therefore, I believe it's still reasonable to infer a connection between the emergence of hunting technology and the disappearance of megafauna.

[@davidniemi6553]

Clovis First is not entirely bonkers but also not entirely true -- there are clear indications of modern humans in the Americas thousands of years before the Clovis era, but the ice age climate did not permit them to grow to the numbers needed to have a big impact. I would expect them to have followed coastlines until they got to promising unglaciated areas, and then to try their luck here and there inland, but fail to establish any large long-term cultures until the climate got more forgiving. And, most of those coastal areas are far underwater these days.

[@SatchwellSavitts]

Wow! I never knew that giant armadillos existed. I always thought armadillos were small burrowing creatures. It's amazing to think about all the giant creatures that roamed the Earth during the Pleistocene Epoch. I wonder what other creatures we don't know about?

[@HuckleberryHim]

There is still the giant armadillo today, which can weigh over 100 lbs

[@onenewworldmonkey]

Your videos have evolved. You are much more comfortable. I must relay a quick story: In the 70s, as a kid, I loved to go to the Carnegie Museum in Pittsburgh. Of course, I loved the dinosaurs (especially triceratops) but I always made a bee line for a taxidermy showcase of two sabortoothed tigers attacking an Arab on a camel. The Arab had a curved knife defending himself gallantly. Eventually, to my chagrin, they got rid of the display because it was too inaccurate for they didn't live at the same time. Additionally, I'm not allowed to say sabortoothed tigers anymore. I also cannot say "American Indian, Oriental, and perhaps even "bee line"? You probably don't even know what a bee line is. When searching for honey one "lines" a bee. In other words, watch a bee collect pollen. It then makes a bee line to its hive, which you follow. What is right today, wont stay right-just sayin. Our being a predator has a negative connotation today. It shouldn't. We've evolved into it for a few million years. You may attack a black friday sale as though it were a herd of deer, but don't know it. We are the reason all those animials in your video disappeared.

[@chilirasbora]

Man had to eat they must have been pretty good

[@paulmryglod4802]

As a kid, i always dreamed of being able to time travel to the pleistocene era to see all the megafauna. This was after my initial thoughts about traveling to see the dinosaurs, but i figured i might get eaten by a t-rex.

[@Insightfill]

I had just read about the isolated "mini mammoths" last week. So sad. The breeding population got so small that it started really messing them up.

[@deadpoolrlz9685]

I would love to live an alternative timeline where pleistocene megafauna never went extinct

[@josiahpappan5122]

The thing I have a problem with is the over hunting as a direct cause of extinction. I know of mass graves of bison being driven off cliffs, but over hunting of mammoths? They were indeed large, but could it have been there were not as many in the first place? Maybe they were not so heavily populated at the end of the ice age and their decline made it easier to hunt. I wouldn't say it was a direct cause rather than an opportunity for humans to take advantage of the situation.

[@GEOGIRL]

Absolutely, extinctions are always more complex than one singular cause can explain :)

[@nuclearnyanboi]

gawd I love this channel

[@GEOGIRL]

[@thoth8784]

Mankind HAD to show up and RUIN everything! Now look how fd up everything is!

[@neotericrecreant]

I like the anthrocothere. they are so cute.

[@jasonpike9626]

I wonder why the straight-tusked elephant Palaeoloxodon antiquus, which was alao an animal from that time, went extinct.

[@jasoncuculo7035]

Rangel Island Mammoth extinct 3,750 years ago, humans appeared their 500 years later (3,250 years ago). In that case it was a crisis in the food they ate and probably genetic continuity in immune system due to isolation. Human activity did play a role in the extinctions worldwide though. There was also a smaller Sicilian Mammoth extinct (I believe 9,500 years ago), miniature Paleo-Loxodonta on Flores and Komodo Island in the Lesser Sunda region of Sumatra. Although the terror bird age was really the Paleocene there were variations in South America until the Holocene, now only the Red-Legged Seriena bird exist from this lie but is the size of a roadrunner.

[@williamnelson5995]

Good video, the Younger Dryas is an interesting twist, but it's awfully hard to believe that even a somewhat faster cooling/warming could have substantially impacted such very widespread species that were all highly mobile and had endured millions of years and many ice ages previously. As you say, the timing of human arrival is real suspicious....

[@malleableconcrete]

I think the current thinking with the Short faced bears, either Arctotherium or Arctodus, is that they probably weren't very carnivorous, this is supported by their large size, close relatives (Brown bears are already quite vegetarian, but Short Faced Bears's closest relatives are Spectacled Bears who's diet is over 90% plant matter, its only really Polar bears that have specialised into a large obligate predatory role), teeth morphology, lack of appearance in predator traps like the La Brea tar pits and I think some work done on the isotopes of their remains that suggest a diet where meat was rare. If that's the case they probably weren't much effected by the declines in potential prey items in contrast to Lions, Saber-tooth cats and Wolves in the environment around them.

[@hoibsh21]

THat's the question: Where did these giant cuties go to?

[@glenncordova4027]

Our stomachs.😋

[@marchismo8514]

I have a really tough time believing this insistence that ancient humans were a major factor, if any, in the Pleistocene extinction. Claiming overhunting is quite a stretch to begin with, seeing as hunting (which needs sustainable practices to endure across time in any environment) was the profession of ancient humans for hundreds of thousands of years, and this practice must've been especially high-level for those people entering the America's given the vast span of time prior to that living sustainably and migrating across the massive continents of Africa and Eurasia. The people were the same, their approach to the fauna and flora of new environments would have been similar. The megafauna were either very similar to the rest of the world, or at least filled the same niches that existed elsewhere. We underestimate ancient humans and how complex their lives were. Living with multiple Homo relatives and a vast array of giant megafauna, nothing even comes close to our lived experiences today or even 200 years ago. For context, this overhunting hypothesis claims that >70% of all animals larger than a medium-sized dog, across 2 continents, in the span of just 2k years, were driven to extinction by a people who spent hundreds of thousands of years coexisting with the same or similar megafauna, including our Homo relatives, in the same or similar environmental niches across the rest of the globe. On top of that, the evidence for humans in the Americas goes back at least 10k years before the Younger Dryas began, so to start with there is no correlation of human arrival = extinction. That doesn't even apply to the rest of the world. So it doesn't make sense that for hundreds of thousands of years people managed to not destroy megafauna across the globe and yet we ignore all of that and insist that because humans have the capacity to be barbaric they must've gone on a blood rampage and eradicate 2 continents worth of megafauna. It's a naive line of interpretation for an obviously complex and very fascinating history.

[@lucash7012]

How come we are trying to revive wholly mammoths and not giant armadillos!!??!?

[@GEOGIRL]

I think it is because we have more complete genomes reconstructed for the mammoths than we have for the glytodons :)

[@cooperdozier7406]

😄I'm sure the defining weight for megafauna is not meant to refer to babies like you say, BUT from a cursory look at google results, elephant newborns can be 200-250 pounds, blue whales newborns 5,000-6,000 pounds, hippos can exceed 100 pounds sometimes, and walrus often. Moose newborns only clock in at 28-35 (max 45) though and polar bears a surprisingly small 1.5 pounds. So some babies *do* in fact exceed 100 lbs at birth 😃

[@cooperdozier7406]

The Game of Thrones books are far better than the TV show anyway. But they might still be hard to put down and I'm sure your very busy with your career and etcetera. Book 5 came out in 2011. Book 6 is still not out though I think I heard it's finished and they're sposed to be at least 7 or 8 books, which will be diverging from the plot in the show... I didn't feel the need to rewatch the TV series after I binged it that one time

[@jeffmcneel6859]

The sloth, likely evolved slothiness as their movements resembled breeze blown movements of trees & leaves (not known yet), the giants were likely losing their slothiness, being a sever handicap

[@Dragrath1]

No mention of the cave lions or American lions Yeah wholly mammoths lasted until around ~4,000 years ago or so on Wrangel island ultimately dying out due to the lack of sufficient population size and diversity to prevent inbreeding to the point of genetic collapse. Its a tragic end really if only Wrangel island were larger though were that the case people probably would have found and settled it sooner. Just as the the mammoth steppe was maintained by mammoths the same is true with African Savanah elephants which play a critical role in their preference to uproot trees to eat their roots I wouldn't be surprised if mammoths had a similar dietary preference. Interestingly based on fossil cataloging the most common North American herbivorous megafauna at least those represented in the fossil record so we may have had a bias in preservation as well) were horses followed by camels I should note that the timing of human arrival in the Americas has been pushed back to over 20,000 years to a largely unequivocal degree by some recent findings which makes the connection less precise. Based on the La Brea evidence and the recent calibration resolution letting us know how the tar effects the carbon isotope ratios and what we now know about indigenous American processes it appears the herbivores loss occurred during the Bølling-Allerød directly following a drastic change in the pollen and other plant fossils found which suggests that land use was probably a dominant factor as thick charcoal horizons date to this time of transition and the pollen which survived the event are all fire adapted and or dependent species. This also fits the patterns seen with the other known example of a Human naive ecosystem across the greater Australian landmass (also known as Sahul) as the post human flora have become much more dominantly fire controlled. Of course the areas effected by this are particularly in fairly arid climates to begin with so this might not have generalized more globally but the shift towards shorter more intense fire regimes with the arrival of humans or the absence of this impact where humans were not present in an area appears to be a much more broadly distributed. Hunting certainly could and probably did have an effect especially for k selected species which can't tolerate high population losses to predation but to me it is looking like human impacts on the landscapes are likely a bigger impact. I also can't help but wonder if the higher rate of insect diversity for fire adapted species here in the Eastern US might be a consequence of this impact though whether this is a trend outside my local ecology is something I don't know about. As for the Dire wolf it had/has long been assumed that they were closely related to wolves and coyotes based on apparent shared characteristics but a few years back their genome was successfully obtained and studied revealing that they were actually part of the south American canid branch with their similarities to wolves and coyotes being an example of convergent evolution. This does solve the riddle for why there is no evidence of them genetically mixing with wolves coyotes and dogs which are all genetically cross compatible resulting in viable offspring. Another curious possibly related factor is that there actually was an early extinction of some megafauna particularly sabertoothed cats within Africa which seems to correlate suspiciously well with the rise of Homo Erectus the earliest human ancestor to show evidence for the control of and use of fire. Given these were the common ancestor of Homo sapiens Homo neanderthalensis and Denisovans the link between fire and these species is pretty deep which potentially further bolsters the argument for fire ecology driven factors.

[@v_zach]

Yes, please cover Holocene mammoths. 😎

[@JungleJargon]

Sooner or later people are going to have to face the fact that the continents broke apart in the days of Peleg, 100 years after the global flood. * It’s the reason for the glacial striations stamped on top of bedrock like a gigantic broken seal in South America, Africa, India and Australia from glaciers that were moving from south to north from the time when they were all still connected to Antarctica at the South Pole. Of course this was after the sediment layers from the global flood were deposited. * It’s the reason fossils and sediment layers line up between South America, Africa, Madagascar, India and Australia. (The fossils and sediment layers were deposited first and then the continents broke apart, 100 years after the global flood.) * It’s also the reason there are many frozen animals and forest ecosystems buried by tsunamis from the rise of sea levels in North America and Siberia as the continents were being shoved into the Arctic from the centrifugal force after the earth broke apart, possibly due to hardening of the sediments and other factors. * It’s the reason animals made it to South America from Africa and humans did not since they were still trying to build the Tower of Babel before the breakup of the continents. Jaguars were separated from leopards, greater grisons were separated from African honey badgers, tapirs were separated from …tapirs, otters were separated from otters and all of the other animals arrived at various places around the world before the breakup of the continents. * It’s the reason why the lifespan of humans was cut in half a second time since the global flood from a less than 500 year lifespan to a less than 250 year lifespan. * It’s the reason why the meaning of the word Peleg in Hebrew that meant “divided” turned into “as (where) the waters flow” in the later Aramaic form of Hebrew. That’s quite an impressive change in meaning. * It’s the reason people isolated into family groups and began speaking their own language. (Everything that happens is of course by the power of God.) *Last but not least, it’s the reason penguins never made it to the Arctic since there was no land there for them to breed in the Arctic. …And now you know the rest of the story, the whole story.

[@megalotherium]

:0 omg this show is about me

[@mqcapps]

How many humans are we talking about...and how many megafauna...sounds like a few hundred

[@davidniemi6553]

By 10,000 BC or so, when the earth was starting to consistently get pleasantly warm, there were many thousands of modern humans in the Americas (my impression is that were a much smaller number of modern humans going back 25,000+ years ago, including in remote parts of South America, but there numbers were so much smaller as to leave few traces and have no impact on Megafauna).

[@Harry_Tick]

I missed you.😢

[@vernowen2083]

The one thing that megafauna needed to survive was high oxygen levels. That's why they either shrunk or died out when oxygen levels crashed 65m years ago. Even human life spans were greatly reduced.

[@stevebloom5606]

Gomphotheres lasted all the way to the end of the Pleistocene. Also, you missed the Australian megafauna. Humans arrived there earlier than in the Americas, so the extinctions are correspondingly earlier. Do an episode on them! Some megafauna extinctions occurred well into the Holocene, e.g, the Irish elk, or even within the modern historical period, e.g. the aurochs.

[@stevebloom5606]

Also the big birdies.

[@tonyp6631]

If you make " mega fauna of the holocene" into a t-shirt, I will buy one😉 also maybe add an arrow pointing to the wearers face like my " I'm with stoopid" t-shirt.

[@GEOGIRL]

Haha I love that! ;D

[@jamesdriscoll_tmp1515]

And giant beaver

[@od1452]

I don't know why the YD happened .. but I suspect the Volcanisum in the Yellowstone area was a major reason. The woolly Rinos and Mammoths lived longer so I don't think that the Human population density was high enough for hunting to really be a prime influence..... unless the mega fauna Gestation and early growing time was very slow. But I don't think there is enough Archaeological Evidence to show Humans as numerous efficient hunters. But I've been out of Anthropology for some time.

[@JeremyBowkett]

Some of the North American Pleistocene megafauna that are with us today are the plains and wood bison and the pronghorn. I believe I read once that some of the populations of plains and wood bison had to be crossbred to save them from inbreeding, but I'm not sure. The modern pronghorn is the last of four genera of pronghorn that lived in North America. Of course, the most spectacular example of a species of megafauna becoming extinct in North America at the end of the Pleistocene and then returning is the modern horse.

[@michaelwood368]

needs more australia

[@dobbersanchez1185]

Mega-pleisto-faunication 🎶

[@silentglacierfang]

7:40, Gomphotheres aren't the ancestors of Mastodons. They are a sister clade. Mastodons are part of Mammutidae while the Gomphotheres in the broad sense are all Elephantida, both clades in Elephantimorpha but separate ones. Elephantimorpha split into Mammutidae and Elephantida as sister clades.

[@footfault1941]

Humans are often blamed for extinction of mammoths & others. One thing not quite clear is in hunting scene of them. Seemingly mammoths were inhabitants of harsh, cold place, which is very tough for the early humans. Is it probably a biased view? Alternatively, mammoths could be seasonally migrants for which humans used to take an opportunistic hunting fest? It seems those wooly giants were away from ordinary human activities (hunting) ecologically. What do think?

[@quantonica5348]

I'm very ok with however you pronounce the names , I still know what you're talking about.

[@toastyburger]

I'm no expert, but I've always suspected over-hunting is a simplification offered by Europeans with a knack for extermination. Many native people have a culture of living in harmony with their environment and managing their resources, and their lack of firearms would make it difficult for them to slaughter animals wantonly. Perhaps that's why the giant wombat (Diprotodon) of Australia co-existed with the Aboriginal people for over 20,000 years before going extinct. I'm not suggesting humans weren't complicit in the extinctions, but it warrants further study. Correlation does not imply causation. EDIT: A March 2024 study by Danish researchers points the finger squarely at human. Their study is a lot more comprehensive than my hunch. See "The late-Quaternary megafauna extinctions: Patterns, causes, ecological consequences and implications for ecosystem management in the Anthropocene" in Cambridge Prisms: Extinction. One telling point is that the extinctions didn't happen suddenly but over time as the human population grew.

[@mohsenalshagdari1686]

informative

[@coweatsman]

Some of these names write themselves. The dire wolf. The situation is dire if meeting one, being so much bigger than the grey wolf. And Smilodon, the smile you would never want to see.

[@HuckleberryHim]

I think this video was good, but it misses a lot. It only covers a tiny fraction of the megafaunal losses, mainly the famous American taxa. Even that is a small sampling of the American extinctions. The diversity of life we lost is truly staggering, from "wombat-lions" to club-tailed horned turtles to giant "ostrich-ducks" to beavers the size of bears, and literally dozens and dozens if not hundreds of other unique examples. I read about this stuff a lot and I still regularly come across bizarre, fantastical beasts I never knew existed, but which humans encountered once upon a time. This gets into the second point: these extinctions were extremely global, affecting literally every single continental landmass and large island in the world excluding Antarctica, and took place across tens of thousands of years (the earliest starting perhaps 100,000 years ago, although 80,000 is a more robustly demonstrable date). The Younger Dryas only attempts to explain one of these events, though it was a big one, involving the Americas. It does even that poorly: it wasn't anything special whatsoever, and climatic fluctuations on par with this or even more intense occurred regularly and never wiped out American megafauna, or had any discernible impact at all, really. The fact that humans arrived exactly coincident with the start of the decline is the smoking gun. It not only happened here, but on literally every single landmass where megafauna went extinct. Every last one of them, without a sole exception, coincides exactly with local human arrival. This isn't a coincidence, as I've said for many years, and in the past few years many very high-quality studies have entirely put this question to rest, with studies looking at both local and global extinctions confirming the "sufficient and necessary" role of humans. None of the other "Big Five" extinctions is thought to have been caused by mild, local climatic fluctuations, though they were similar in scale to this current one. I like that you said that the human hypothesis is not just about hunting. I personally am not sure hunting was even a very important factor, given the sheer scales involved. Humans are more effective at altering habitats, spreading diseases, etc, which are some of the things you mention. I think it is a tragedy that the human hypothesis gets reduced to just "overhunting on steroids", because there is a lot more involved here. Really though, it doesn't matter all that much how they did it. Humans gonna human, and it is very clear from the patterns what the impact of that has been, continuously from 80,000 years ago right up to this day. Otherwise, a few nitpicks: there are a few animals whose babies are actually megafaunal, by the 45kg/100lb definition. Elephants can have newborns weighing over 200lbs, and rhino babies can be over 100lbs. Whale babies are much bigger. I like your overview of proboscidean evolution, but when you say "and finally modern elephants", it makes it seem as though modern elephants are more recently-evolved than mammoths or mastodons (or _Paleoloxodon_, gomphotheres, other recently extinct proboscideans). This is not the case; they are all exactly equally modern. Tens of thousands of years is a blink of an eye evolutionarily. The ones that survived are the lucky ones, but they haven't changed, and if these extinct guys were still around, they'd look and act the same as they did. This applies to all the Late Pleistocene and later extinctions. Giant short-faced bears (_Arctodus_) were probably omnivores, or even primarily herbivorous. The only living tremarctine bear, the spectacled bear, is the second most herbivorous living bear (over 90% of the diet). In fact, all living bears besides the polar bear are omnivorous, and most have at least some populations, at least seasonally, which are very herbivorous. Studies on _Arctodus_ suggest variability, with some bears being very carnivorous and others very herbivorous, very similar to modern brown bears. But I would bet they were more herbivorous overall, as some researchers suggest.