When Birds Stopped Flying

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Ratites have spread to Africa, Australia, New Zealand, and South America. And there are fossils of Ratites in Europe, Asia, and North America too. That’s a lot of ground to cover for birds that can’t fly. So how did Ratites end up all over the world?
Thanks to Ceri Thomas for the Lithornithid reconstruction. Check out more of Ceri's paleoart at / alphynix and nixillustration...
Thanks as always to Nobu Tamura for allowing us to use his wonderful paleoart: spinops.blogspo...
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References:
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academic.oup.c...
digitallibrary....
onlinelibrary....
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[@hyraxy]

i'd love if you guys could do a video about the history and evolution of grass! grass is SO ubiquitous today, and yet so recent, and imagining a world without it is honestly the hardest thing for me to get my head around when i think about past eras in the history of life. what would an open plain even LOOK like without grass?

[@Hashishin13]

There was probably a lot more scrubby land and a fair bit of what is now grassland would probably just be desert.

[@Xn7000]

This is an interesting one. Commenting for additional visibility. =]

[@nuadathesilverhand3563]

Have you ever been to south eastern New Mexico? For those who have, I think enough has been said.

[@Phlebas]

I made this same request a few times in the past, so I'm upvoting this

[@zacharyforbes6086]

you're not the only one@@Phlebas

[@brc9739]

I just wanna say kudos to you guys for taking down a video to correct your facts. Very few other channels match your level of quality and passion for this subject

[@xxDDnicoDDxx]

not only this subject, PBS eons have some of the best researched videos and they're the best imo

[@KhanMann66]

How many KZbinrs out there will willingly re-record their own video just correct a mistake? Very little. Kudos to PBS for going the extra mile for us.

[@ShouldBeKnown]

@@KhanMann66 Another educational channel did that -- kurzgesagt. Kudos to both of these channels!

[@RobertEgbers]

These guys should be very proud of their work. Best efforts scientifically and entertaining without being sensational or reckless. Great job!

[@TeganThrussell]

What mistake did they make?

[@Mrblacksabbathfan]

Wow, re shooting a video in order to fix inaccuracies. Eons, what a class act. One of my favorite youtube channels. Keep it up guys!

[@johnny1498]

Care to elaborate?

[@BioBush]

This is a great explanation of how similar selection pressures will result in similar body types! In the absence of predators and with plenty of food on the ground, these birds specialized towards getting the food and away from escaping predators!

[@Helmic]

What has me confused though is why nearly _all_ ratites did this. Sure, they filled a niche, but why did all these distant relatives of the same flighted ancestor end up filling the _same_ niche instead of diversifying into several different niches? Why did they all become flightless throughout the world with rare exceptions? Why don't some birds of that last common ancestor keep their flight?

[@Monsolido]

I agree it seems unlikely to be explained by convergent evolution alone... happening 8 times! Surely the ancestor had a predisposition to how its descendants would evolve. Maybe it was particularly prone to getting big and heavy? Makes you wonder what genes can hide.

[@somedude140]

@@Monsolido I think it was because they all came from an ancestor that was a grazing herbivore that nested on the ground/wasn't arboreal. The individuals that were bigger were able to avoid predators better, longer legs meant they could outrun predators, and longer necks meant that the ones with longer legs could reach the ground to eat.

[@trentrubenacker9718]

@@Helmic Some ratites do fly. The modern South American (word I can't pronounce, much less spell) still flies. Similar genetic potential perhaps? Evolution works from the existing genome of the species, so maybe something about the ancestor's genome made it easier for these specific steps to unfold. Or maybe it was something about the ancestor's phenotype. If the ancestor was a convenient shape to take this role with little phenotypical change to body shape, a change in size is one of the quickest and easiest things that happens in evolution. So, the ratites didn't have to evolve very much to go flightless, they just tended to get bigger because bigger is an easy transition and happened to drop them beautifully into the land predator niche. Edit: continued reading and Christian Schiller's idea is the thing I was trying to say about the ancestor's phenotype put better.

[@rahowherox1177]

No such absence of predators in africa.

[@festerallday]

This is always how we viewed this in Hawaii. Most birds and trees here developed gigantism due to lack of predation. Birds got large and lots flight, seeds got large and didn't go far from the parent plant. We had the Moa Nalu, which was a giant goose the size of an ostrich. The native Polynesians hunted them extinct too.

[@Tsumami__]

Delicious giant goose dinner is hard to resist

[@jasonvoorhees5180]

It was called the “Moa Nalo” and it wasn’t the size of an ostrich at all they grew to a maximum weight of 16 lbs. no bird in the history of the Hawaiian archipelago ever reached ostrich size for that matter not even the giant flightless geese www.pnas.org/content/99/3/1399

[@whitewolf3051]

Hawaii giant bird *aside,* only *if* humans didn’t hunt the giant flightless birds to extinction, but try to ride them, then we could still have them to ride.

[@festerallday]

@@jasonvoorhees5180 you are wrong. The giant goose was the size of an ostrich. Bones have been found. Go to the Hawaiian section of the university library. There is stuff there that is not published. Or just ask anyone in the evolution and ecology department

[@sairajmenon556]

​@@whitewolf3051 The countless ethical dilemas in both cases aside, I do have to agree that it would be better to have a giant flightless bird to ride than a giant flightless bird to just see and know some cool stuff about 💀😅😭😂

[@primoattilio5207]

Grazie.

[@Linkous12]

So ostriches split from the other ratites before the extinction of the dinosaurs. That's pretty neat. Makes you wonder what the common ancestor looked like.

[@threeomgthree]

Sans Handlebars Every species of non avian dinosaurs were killed by the extinction event.

[@IWasaTeenageTeenWolf]

@@trvth1s I thought bats were considered the most wide-spread and diverse vertebrates.

[@IWasaTeenageTeenWolf]

@@trvth1s Actually, you forgot about orcas and leopard seals. They're common in Antarctica and, well.....they're mammals. In general, Antarctica is so brutal there's less lifeforms there than many other places. Now the North Pole, which is just as hellish as the South......that's swarming with mammals both on land and the sea. And honestly, there ARE bats that live in the deserts. Have you ever seen the millions of free-tail bats that swarm all over Mexico and all through the Americas?

[@ibbi30]

@@trvth1s Modern birds belong to the clade Euornithes, at least according to Wikipedia,, so the clade did survive the extinction event, but its clear from a quick search that the clade was heavily pruned and many basal lines.

[@ekosubandie2094]

probably a bird that look more or less like tinamou

[@nakenmil]

Birds went back to the ground. Mammals went back into the sea. Evolution is funny that way.

[@genebijou3772]

Perhaps to fill in the roles of other extinct species.

[@Ezullof]

That's only something you would think if you first made the addumption that evolution went in a certain direction, though. Evolution doesn't go from water to see, or from ground to the air. That's a wrong way to teach it and to understand it. And it's been known to be wrong for decades.

[@Hashishin13]

The birds actually did go from the ground to the skies and back again. The mammals left the ocean long long ago and returned. Evolution doesn't need intent to have a direction, especially in hindsight. We are describing where the process takes things as a direction, not that the process decided on a destination intelligently. OP was right, even if he sounded misleading to you. @@Ezullof

[@RRW359]

And then mammals ALSO decided to go to the skies.

[@ScionStorm1]

"Go home, Evolution. You're drunk."

[@beretperson]

Demon ducks? You mean geese?

[@ScionStorm1]

Mateo Gg *Black Swan and the Demon Ducks* Sounds like a great band name.

[@lauranolastnamegiven3385]

why do people run from geese? they have no teeth! they can't hurt you, their beaks aren't even pointed

[@lauranolastnamegiven3385]

@Mac Mcskullface please explain to me why I'm wrong, I really don't understand how a goose can hurt us (NOT sarcasm)...I understand being intimidated by something charging at you, but if you stop & think, what's the worst that can happen, non-pointy beak, no teeth, no talons...?

[@iacopoguidi7871]

@@lauranolastnamegiven3385 geese are quite strong birds, and even with no teeth their bite can be really painful. It won't kill you but will definitely hurt. Besides they also flap their wings at you, which again are quite strong, and being slapped in the face by them it's not pleasing either.

[@daynanielsen6956]

@@iacopoguidi7871 Geese are everywhere in Canada, and its known here to steer clear. A simple smack from a wing would break anyone's arm, cause internal bleeding, and not to even mention the claws they have on their feet... Don't mess with them ;)

[@Len124]

So, essentially, flightless birds were an attempt by dinosaurs to reclaim their dominant position on the ground following K-Pg, but were largely outcompeted by mammals.

[@normalmighty]

Moas only thrived for as long as they did because NZ had 0 mammals before we came along.

[@Len124]

@@normalmighty Yeah, it's interesting to see how strategies for filling certain niche's converge or diverge on an island like NZ where the fauna are almost entirely birds (aside from bats), compared to continental ecosystems where mammals mainly dominate. The Kiwi could be compared to a hedgehog, the elephant bird you mentioned could be seen as filling a similar role to large ungulates or other megafauna, and so on.

[@danbennett2891]

I feel like there needs to be a separate video that focuses soley upon the matter of avian dinos surviving the mass extinction event that wiped out all non-avian dinos. Do we not have more information about how this might have played out? Or, are we merely supposing that's what happened? I hope not...

[@Len124]

@@danbennett2891 I'm super interested in that topic too. Though it's not exactly dedicated that topic, it does touch on it more in this one: kzbin.info/www/bejne/h3i1ZqyFp6ibg6M

[@lasagna4layf132]

Lolololol

[@LazyCat010]

So when the non-avian dinosaurs went extinct, some avian dinosaurs became a little less avian.

[@nolanwestrich2602]

That's how niches work. When the ____ disappears, it's time for a completely unrelated animal to become the ____.

[@Ezullof]

@Nolan Westrich well not exactly - that's a rather specific kind of niche filling called "convergent evolution". Niches means that different animals will develop the same evolutionary function. For example, eating insects that live in trees. But they will develop very different tools to adapt - some will have strong beaks and weird tongues like woodpeckers, other will have long claws, sticky tongues, flight capabilities, gliding capabilities, agile arms, agile tail, some will be nocturnal, some will have a very good hearing... etc. Convergent evolution happens only when two undirectly related animals develop similar characteristic to adapt to similar needs.

[@Irken_Invader_Zim]

Nolan Westrich except birds are literally dinosaurs... the same animal that used to be in those niches...

[@s0ul216]

@@nolanwestrich2602 Does that mean there should be the possibility of a humanoid species (the one who isn't related to primate) too back then?

[@KippiExplainsStuff]

@@s0ul216 no. Humanoid is a very new addition and it can't just appear in one go. Evolution doesn't work that way. We would have found some evidence of this by now had there been one.

[@gilberthjimenez431]

Hey guys! Thank you for being so awesome! And thanks for correcting yourselfs (even thought I didn't notice the mistake in the beggining, it is great to see that you take so much care and like so much to give us good information) Anyway, thank you for everything!! And I'll post my first comment again XD Moa's Ark Badum tss! Hahaha Great video guys!

[@hotwaterisspicy]

Gilberth Jiménez right? That’s a lot of integrity! This channel is really great!

[@evaristegalois6282]

0:21 *Giant Moa versus Haast Eagle* Truly a battle for the ages!

[@DRiungi]

bird-on-bird violence

[@bdf2718]

But it's because of humans that there are no moa.

[@ScionStorm1]

When your Pidgeot attacks a Dodrio. :P

[@nathanlevesque7812]

@@londonjackson8986 I wouldn't rule out hte possibility of a jump kick. Cassowaries love doing that and they'll attack anything, even cars.

[@thetitanian5544]

@@londonjackson8986 ha,no moa

[@koaasst]

pretty cool to see up to date production like this. on television you dont get this kind of personal feel. grats to you guys taking the vid and correcting it. that part made me want to not miss any future updates!

[@C0rmac0Neill]

I love the graphics in this. The one of them in descending height order or the Moas Ark one would make great posters

[@sherylhosler9487]

This is awesome because just a few weeks ago we had a researcher working on this topic come to our university department to give a talk. The analyses of these fossils are FASCINATING!

[@Ngamotu83]

Fun fact: It was actually the big flightless moa that brought about the extinction of the massive predatory raptor known as Haast's eagle. More specifically, due to humans hunting moa to extinction, the Haast's eagle lost its main prey and went extinct.

[@ryangshooter_1682]

You know what they call that a keystone species

[@jadetamplin9150]

Id love to see a video dedicated to the haasts eagle

[@ronwastney2530]

There was a high possibility that Maori contributed to the Hokoi extinction by having to defend themselves from eagle attacks

[@whitewolf3051]

Too bad those humans didn’t think to try and ride giant moas instead of hunting them. We *could* still have giant moas, to ride around on. Same with elephant birds.

[@Shiver020]

I really really really do love this series, keep up with this awesome show.

[@chrissscottt]

Here in New Zealand we have a flightless bird called the Takahe which plainly evolved here. We also have a flying bird called the Pukeko which arrived here a few hundred years ago from Australia. But if you compare the two, you can plainly see the Takahe evolved from a much earlier Pukeko ancestor which kinda proves birds lose their ability to fly through evolution.

[@phoeix940]

You also have that adorable Kakapo,, =D

[@kiranroye6498]

intrestingly enough those two birds are in the same genus

[@HappB5]

new zealand is so cool

[@afunnymonkey4948]

Can you discuss African mega fauna next video? They are fascinating

[@martink9701]

are we talking modern or Plio-Pleistocene?

[@afunnymonkey4948]

I would like to see both, they could discuss the evolution of the African mega fauna and how they adapted to the change of the climate and the rise of humans

[@KhanMann66]

Or better yet, how is that Africa is the only continent to have multiple surviving mega fauna, where as everywhere else they have either 1 surviving species or they're all extinct?

[@quen_anito]

Yep! African mega fauna seems to have been better at surviving the rise of humans. Why is this? I want details... Copious details.

[@Bastonikov]

@@quen_anito Maybe because we evolved around them? Dunno, but that sounds like a great vid idea!

[@hokostudios]

That poor Moa. But moreover, that poor Haast Eagle, from whom you cut out an entire claw!

[@danielborza4399]

That's the most unbelievable story you ever shared with us. The same change occuring 6 times independently? Wow

[@olivialea2223]

i’d love to see an episode on the evolution of other modern bird groups and the diversification of birds in general!

[@annikathewitch3950]

The ratites are one of my favorite groups of dinosaurs. Mostly because of The Great Emu War(TM). (For anyone who is unaware of this spectacularly hilarious historical event, Australia declared war on Emus in 1932. Like. Actually filed a formal declaration of war and everything. The Australians lost, largely because, as it turns out, emus are remarkably resistant to machine gun fire.)

[@gavinoaw]

YES, I've been waiting on a video about flightless Birds! Great video, thanks guys!

[@veggieboyultimate]

7:08 funny you should say that because the moa was considered to an a candidate for de extinction, I may not know how long it will happen but it was talked about.

[@benroberts2222]

I'd like to see something on ancient gigantic fern and horsetail forests, perhaps including stuff about the isolated Pacific islands that never saw gymnosperms or angiosperms make it over.

[@johannfuchs4566]

I absolutely love this channel. You, presenters, are too good. Huge respect. ☺

[@Lightning9060]

In New Zealand we didn't have many predators until humans bought rats over, then stotes to deal with the rats, then possums to deal with the stotes and rabbits. So with little to no mammals for millions of years Moas and Kiwis lost the ability to fly in order to live more efficiently, safe energy by nof flying

[@soko4710]

stoats, weasels, and ferrets were imported only with the intention of them controlling rabbits; not rats.

[@soko4710]

and possums were imported for their fur; not for controlling the other pest mammals. smh!

[@phoeix940]

I've also read about the Stephen Island wren (smallest flightless bird) that was supposedly exterminated by a single cat, haha... Poor thing. Really like flightless birds in general, but most of them are extinct due to introduction of rats...

[@soko4710]

@@phoeix940 that is a common claim, but in reality, it was several cats that contributed to the extinction of that wren. additionally, it was also present on the mainland before being restricted to Stephens Island, but was rapidly wiped out there after the introduction of Pacific rats.

[@whatshappenedhere1784]

@@soko4710 ikr, i've seen stoats maul possums to death

[@paulonion542]

You guys are awesome, such a knowledge dump in every single video

[@Boom12]

Great work on being gracious to take up your time to correct a mistake. Not many on KZbin do, so a big pat on the shoulders for all of ya. Since today touched on flightless birds, how about Penguins, or how different mammals or reptiles adapted to the water?

[@highwayfrog23]

Probably one of the best eons videos

[@PepinsSpot]

"Human beings, eating their way thru the world since 200,00 BC!"

[@Showmaann]

This is so fascinating man, the world is incredible

[@mistergrieves]

In fact, the same exact evolutionary process is underway with the rails (Rallidae). Species everywhere are losing or have already lost the ability to fly. Just like the ratites, they’re cosmopolitan; every continent-every island-seems to have its own species. The best example is the Inaccessible Island rail in the Tristan archipelago. It’s the world’s smallest flightless bird and it’s in (one of) the world’s most isolated places.

[@phoeix940]

And they paid for that; most of them became extinct due to introduced animals... Poor Laysan rail... I thoughts the smallest was the Stephen Island wren, though extinct, and was supposedly exterminated by a single cat...

[@mistergrieves]

Phoeηix I meant extant, but otherwise you’re probably right. The related New Zealand rock wren had also been losing the ability to fly but who knows what will happen now.

[@phoeix940]

@@mistergrieves Woah, didn't know 'bout that extant wren, :D

[@dulcearias3676]

I don’t know how I stumbled upon this channel a couple days ago, but I’m obsessed!

[@DustyGozongas]

As first Lady of New Zealand, thanks for correcting the mistake. Also this guy is a daddy. That is all, thank you.

[@willcrago4463]

L Johnson 😂😂☠️ right!

[@grobanlover292]

The best explination I heard for the Australian extinction event was that when humans came to Australia, we instituted Slash and Burn techniques to create arable land, which destroyed the environment enough to lead to the extinction of the megafauna

[@Musketeer009]

First! Or the Common Ancestor to everything.

[@Jesse__H]

186th! A distant relative.

[@kamoroso94]

Hello, LUCA!

[@AngryMothNoises]

They all ready talked about it

[@siyacer]

@Jose Castro lol

[@ApotheosisTK117]

I would love to see a video focusing on the history of prehistoric rhinos, there were so many awesome kinds and different adaptations and even some that survive to the present day!

[@Dinoman972]

Ah, our old friend: convergent evolution.

[@arandomdude1992]

Yes

[@Dodoraptor4]

Haast eagles had a huge disadvantage: They were so specialized at hunting the huge flightless birds (which they were amazing at) that when those went extinct, they couldn’t effectively hunt anything else.

[@Dodoraptor4]

London Jackson but they weren’t effective enough in doing so.

[@Devin_Stromgren]

Hmmm... Makes you wonder what physical or behavioral adaptation made the radites so predisposed to becoming flightless in the first place.

[@mennol3885]

Came here to ask this question. Also with other lineages, it seems to occur many times that a predisposition is build up in a species over a long period of time and then some quick adaptations happen when a nearby niche comes available.

[@dracodracarys2339]

Sort of like how limblessness evolved so many times among squamates giving rise to amphisbaenans and slow worms and glass snakes aside from true snakes, or how eusocial lifestyles evolved multiple times among the hymenopteran insects like ants, bees and wasps? Perhaps they were just better at ground life that gave them the upper hand to more flight-specialized birds, since flyers tend to be poor runners?

[@MuertaRara]

Ratites are my favourite birds, especially Cassowaries! :)

[@xdizzy12]

Could you do a video on the history of our senses? Our seeing, hearing, smelling, tasting and feeling of the world around us? Maybe you could do a series on it. It's something literally everyone can relate to.

[@frostyguy1989]

Here's something insane to wrap your head around. Remember that giant Haast Eagle that hunted Moa? The largest eagle that ever lived has an ancestor that's still around today: a bird called the Australian Little Eagle that is 10-15 times smaller, and evolved into a giant between 700,000 and 1.8 million years ago. That is the fastest and largest evolutionary increase of any vertebrate species ever recorded.

[@Helmic]

I find it weird that the ratites all filled the same niches, though, coming from flight-capable ancestors. You would think that at least some ratites would keep that ability to fly and fill other niches. Did the birds that flew across the continents just have something in their genes that made them likely to grow really big? If so, does that mean that genetic quirk was originally selected against and then started being selected for over and over again? And if that's the case, what changed that made those too-big birds stop dying and start thriving?

[@donotcare57656]

Maybe the one's with flight just couldn't compete well with other birds with flight, and as such only their flightless descendants survived.

[@trentrubenacker9718]

Perhaps it was a phenotypical factor rather than a genetic factor that accounta for the convergence. The common ancestor was large and land dwelling (rather than arboreal), but capable of flight.(geese nest on the ground but fly amazing distances) When the dinosaurs went extinct, the land dwelling lifestyle suddenly had a lot of free food around and way fewer predators, making flight superfulous and size advantageous.

[@Burt1038]

Maybe that bird family was never really good at flying. Kind of like chickens/junglefowl.

[@stephan1330]

@@Burt1038 nah its just millions of years of evolution and the lack of mammalian predator's.

[@StonedtotheBones13]

Just came from a video about early birds on scishow. It mentioned a theory that birds only grow so big bc unlike pterosaurs, they (primarily) use their legs to launch themselves into flight. I'd need more support for that hypothesis, but in the meantime maybe these guys just had some absolute gams. I'd imagine the total body size is more related to isolation and lack of predators tho.

[@lbms3]

One of the best channels on KZbin

[@jayjayspoon8824]

No Moa, no Moa, in old Aeotearoa. Can't get 'em, they've et 'em, They're gone and there ain't no moa. The old Mori-Ori told me the story Of how the Maori hunted This fabulous bird, feared I have heard, As big as you ever wanted. Using their wits, they dug mighty pits Into which the moa tumbled And as you may think, they soon were extinct While the poor Mori-Ori mumbled.

[@MrLarryLicious]

So interesting! Weird that stopped flying in so many geographical locations.

[@davidmccarroll2280]

I'm from New Zealand. So thanks for this

[@noctusowl]

I thought I was going mad as I was sure I got notified before. Thank you for correcting and reuploading de vídeo

[@jonashopper4113]

I would love to see a video that talks about the evolution of seahorses? What do prehistoric seahorses look like? What did they evolve from?

[@mohit5496]

3000 years.. that's so early. Man i wish these amazing creature were still alive

[@actionwd]

Love your videos! I know you guy have already done a video on the Avalon Explosion but I hunger for more information about the Ediacaran period in general.

[@emilyanderson8504]

I could see road runners turning into flightless birds. When I lived in Texas they will actually chase your car on foot down country roads 😂. They just like to run fast lol

[@neilc.8368]

The fact that Haast's Eagle looks like the eagles from Lord of the Rings, and BOTH those things took place in New Zealand blows my freaking mind.

[@yoo7289]

I learned so much about the ratites that I didn't know thank you

[@quantumintellect7261]

Also the Zealandia continent after separating from Australia became submerged making it impossible for kiwi or Moa to reach New Zealand without their ancestors having the capacity to fly.

[@stephan1330]

actually evidence suggests that Zealandia never completely sank as there quite a few fauna that have dated back to gondwana like tree ferns, the tuatara and the saint bathans mammal. if new zealand did completely sink than they would have been wiped out.

[@sakurasweet5625]

Absolutely love your videos, so informative and fun!

[@johnnylama7803]

I Love this Channel💖💖💖

[@SteeIdancer]

Darn this time I wasn’t early. Still keep making awesome content! I learned a lot from this video

[@Tobberz]

PBS: What the BBC online presence should be

[@matth7448]

PBS is rocking on youtube

[@Irken_Invader_Zim]

Seeing those big flightless birds are really the closest thing to seeing dinosaurs...

[@DrThunder88]

Excellent work, as usual! I'd like to know more about the distribution of marsupials.

[@BornAgainCynic0086]

Bloody Cassowaries, give me the shivers. Cranky bloody things.

[@stankyratman5685]

This feels like too hard of an attempt to be Austrian to be real mate

[@MuertaRara]

They're beautiful!

[@slamyourheadin9449]

@@stankyratman5685 Austrian?

[@marcob1729]

Evolutionary inertia/trajectory is fascinating. Very cool how a group of closely related animals tend to repeat the same adaptation independently

[@DannatiNomiUtente]

5:18 I genuinely have never understood this illustration

[@Im-Not-a-Dog]

Thats a Terror Bird in combat with the extinct Three-Legged Saber-Toothed Contortion Cougar

[@DannatiNomiUtente]

@@Im-Not-a-Dog ye thanks, figured as much, i was referring to the way the cat is twisted, seems rather odd to me

[@Naltddesha]

Thank you Eons! I'm so happy I found this channel. It's right up my ally!

[@carolinekleo1]

Hi! I love the show! Can you do an episode explaining which ancestors penguins evolved from please? Thank youu

[@MrPeach774]

Since you took down the other video here is what I would like to see covered: sloths! How we went from giant sloths to tree sloths and why they are so different and their evolution in general

[@eons]

Oh just you wait! We have something really interesting in the works. (BdeP)

[@gretchenwetzel7313]

I second sloths

[@guillermoserranonajera1243]

Thanks for your wonderful .videos! I have a questions: Are the ratites ancestors more prone to evolve into giant flightless birds than other groups of birds? and if so why is that, do we have a clue? Great channel!

[@BrainInAVat7]

Would be cool to see a video on how animals that appear to have changed little over eons have been evolving in less apparent ways.

[@LuisAldamiz]

The "molecular clock" is anything but reliable: it can give some indications but it's not proof of anything unless clearly calibrated to (preferably) several ancient DNA specimens. When this is done, at least in the cases I'm familiar with, which are humans, the ages tend to be quite older than with the basic model. It should never be used as evidence: it's not evidence, just a clue to be pondered with great care and always in agreement with other clues such as fossils, etc.

[@rohanshirodkar8353]

I think the birds lost their wings before they grew big. Why? No matter how large the wingspan of any bird, they can only lift so much weight. The birds with the largest wingspans today are eagles, and the video itself said that Moas were bigger than eagles, and heavier. This meant the moas would need MASSIVE wings to host that big (and heavy) body. Those wings would also consume more energy to fly than any bird could collect, especially a bird with a diet of ferns.

[@elizabethhutt7743]

Ostriches are jerks (I used to work at a zoo), but this was still a great episode, lol. 😀

[@crpth1]

Hehehe so true. While visiting a Ostriches farm in Portugal. I had to duck and step away from one of the fences... One was just about ready to bump my head over the wire fence. LOL :-) Well in Africa was much the same with the "wild" ones. We just had to stay away from them and all it´s fine. Specially while the youngsters or eggs are nearby.

[@lauranolastnamegiven3385]

if you kept me in jail, I'd be a jerk to you, too

[@lapis591]

Probably because they shouldn't be incarcerated.

[@tylerrunyan1428]

so we imprisoned the ostriches for no reason and they the jerks

[@aplaceinthestars3207]

Whenever the subject of colossal flightless birds comes up, my knee-jerk reaction is "WANNA RIDE IT" until I think about just how terrifying emus were when I'd seen them in person.

[@yanksmc7]

I watched the1st video...So naturally I watched this one as well lol. Nice job going back and fixing the video to be factual!

[@vinicius2uiciniv]

Could you tell what exactly was wrong with the first video?

[@PurpleTurtle7288]

Thanks again for another great video!

[@AyeGee721]

If only my ancestors didn't hunt all the Moa to extinction- we Maori love KFC so imagine the possibilities.

[@someonerandom8552]

AJ G Lol! All the mega buckets and feasts. And still enough bird for some wicked wings.

[@lapis591]

@@someonerandom8552 Yeah, this kind of mindset drove them to extinction in the first place.

[@someonerandom8552]

Omega Indeed. At least they died for a cause. Think of all the animals killed simply for their horn or tusks.

[@apoena-allnitemusic7203]

This channel is among my favourite on youtube. I am Brazilian so english is not my natural language. On this specific video for the first time it seems to me the commentator was speaking too fast. You may want to watch out about this guys. You probably should consider the relevance of the audience you have from countries that are not native English speakers.

[@mslindqu]

Very much enjoyed this episode. Thanks for the fix!

[@Rhaenarys]

That's actually an interesting, albeit sad, way of viewing how we caused a species to go extinct, one not usually thought about. The earliest humans used to store water in the ostrich eggs, makes sense. Not so much we hunted them for food, but stopped their reproduction in the nest.

[@amphibiousone7972]

Thanks for fixing the information. This was very enlightening. Great!

[@HatredOfMephisto]

awesome content as always

[@darvinator]

Could you do a video on the evolution of jellyfish? Also, Can you release posters of the backgrounds you use to show the time Period (like the octopus in the Ordovician age)?

[@emu5088]

This is so cool! I've been interested in ratites since 1st grade (in the 1990s), even though I'm from the USA. (Hence my username) So many of these facts are band new to me, since I haven't really looked them up since the early 2000s!! Amazing video!! Thank you so much! Shame they mispronounce ratites, though. They should be pronounced "Ray-tights." Thanks for sharing!!

[@RT710.]

What beautiful *BIRBS*

[@mikkicarr5717]

Speaking of flightless birds, I think an episode on the evolution of penguins would be interesting!

[@AlexanderDockham]

You guys are the best! Making sure to watch the whole video again so my like counts. Thank you for being willing to take down a video after a fact check

[@princesslava15]

I love the episodes that are better written and more dramatic than crime scene procedurals. xD

[@simonj3413]

How about the evolution of lemurs

[@Im-Not-a-Dog]

They have that video now.

[@crovax1375]

Life is as mysterious as it is wonderful

[@keithgawain3614]

So avian dinosaurs took the niches left by the non-avian dinosaurs

[@petercarioscia9189]

Omg Yaya!! New Eons 💕💕

[@Dagobah359]

Could you do a video on the animals that have gone extinct because of humanity (all hominins)? Not just a long list, but the underlying themes. (I'm thinking: the megafauna from Africa evolved alongside us so they knew to avoid the dangerous hunter, whereas megafauna elsewhere went extinct right after humanity arrived.)

[@zakcat5175]

at 4:10 i was just like "its convergent evolution, nothing new" XD

[@TeganBurns]

Thank you swag dad!