Elephant birds: Who killed the largest birds that ever lived? | Hacker News Reader

Elephant birds: Who killed the largest birds that ever lived?

bbc.co.uk

80 pointstegeek58 comments

As far as I can see from the article the "birds" were of the ostrich kind, not the flying kind we imagine when hearing the word "bird". As far as I know the modern science also says that many dinosaurs that didn't fly also had feathers. So why aren't the other dinosaurs considered "elephant birds" while this creature is?

IANAP, but presumably "having feathers" does not make one a bird.

Because even though it's all a continuum, this animal was much closer to modern birds than to dinosaurs based on the various ways these things are classified. For one, it didn't have a dinosaur style jaw and teeth but a bird beak. Where to draw the line isn't easy, it's fuzzy, but I don't think this case is fuzzy. These were birds by every way we discuss what that means today (which never requires flight).

Ancestors of ostriches were normal birds that could fly, relation to dinosaurs is more distant.

It is legacy like many things in zoology like taxonomy. They were thought to be more like giant lizards than birds for a long while even if they couldn't ignore the most obvious convergences. It isn't limited just to ones we know about only through paleontology. There is even a civet genus labeled 'paradoxus' that eats mostly berries and fruit despite being under the carnivora family.

The Aristotelian taxonomy was even worse with things like considering beaver a type of fish and poultry as distinct from meat because meat is land animals.

Common names are even worse for it which is why the current lineial system exists in the first place like all of the different names for mountain lion. Taxonomy isn't objective science in itself (although it should be based off of it to be of any use) but it is very useful to science.

Technically we can reindex the taxonomy and rename any time but it would be such a pain to keep track with multiple systems old and new and all of the controversies that it probably wouldn't be worth it until our understand diverges enough that it loses all meaningfulness.

For instance the classical elements of various systems were discarded completely as useless even as an additional layered category. Fire is a state of matter, earth is actually composed of many of the table of elements even more if we don't have metal separate, water is composed of two different elements that appear elsewhere in both air and earth. And the old associations like gold with fire and sun? Completely unfounded. Thus it is pretty much useless as a tool for improving our understanding and limited to a motif.

Meanwhile even if DNA testing shows that the line of descent doesn't match up at all reliably with parallel evolution the organization could still be good for rough body shape for instance. Even if to give a counterfactual and deliberately absurd example it later turns out that humans actually evolved directly from an extinct strain of whale filing humanity among apes is still informative in morphology and not wrong in that sense even if the descent aspect was shockingly discreditted.

I might try to explain this but I think I will definitely miss something or won't be able to articulate. Instead, I would suggest episode 1 of Life of Birds [1].

David Attenborough talks about the evolution of birds, what classifies a bird, where do we draw the line between dinosaurs and birds (he even talks about this elephant bird) in the first episode of Life of Birds [1]. Also, watch the whole documentary if you're interested.

[1]: https://www.imdb.com/title/tt0175394/

Non-avian dinosaurs had a tail and some teeth.

More info http://www.sciencemag.org/news/2018/09/new-find-clears-madag...

Paper http://advances.sciencemag.org/content/advances/4/9/eaat6925...

Were these birds bigger than dinosaurs?

https://blogs.scientificamerican.com/tetrapod-zoology/the-bi...

According to the modern taxonomy, birds are dinosaurs, with a pretty straight lineage.

Thats what I meant to imply. Dinosaurs are a type of bird that were bigger than "elephant birds", so the headline is (most likely) wrong.

Dinosaurs are not a type of bird, just as a rectangle isn't (necessarily) a square.

You have the direction of the time vector descriptor backwards.

I've never heard of a "time vector descriptor", so what do you mean?

Birds are a type of dinosaur called recently avian dinosaur. The other dinosaurs (non-avian dinosaurs) are definitely not a type of bird.

So no, the title is not really wrong unless there is a yet undiscovered bird that's even larger. The elephant bird was the biggest bird (or avian-dinosaur) that ever existed. It was smaller than other non-avian dinosaurs but these were not birds so no point comparing.

The confusion you are making is sometimes described as politician's syllogism. [0]

1) All birds are dinosaurs

2) All land dinosaurs are dinosaurs

3) Therefore, land dinosaurs are birds

https://en.wikipedia.org/wiki/Politician%27s_syllogism

Apparently some people think birds are dinosaurs and other people (sometimes even the same person) think dinosaurs are birds:

'There has been a recent revival of interest in the famous Early Triassic thecodont Euparkeria, and Welman (1995) has discovered a suite of avian-like anatomical features in the basicranium. Paul (2002:179), an ardent advocate of the “birds-are-dinosaurs,” and more recently, “dinosaurs-are-birds” school, admits that, “Euparkeria is a suitable ancestral type for birds … and … Euparkeria is a good ancestral type for all archosaurs.”' https://doi.org/10.1642/0004-8038(2002)119[1187:BADSAT]2.0.C...

I still don't see what this has to do with a "time vector descriptor".

As long as we're on the topic, not all of what we (the laymen) think of as dinosaurs were dinosaurs! Maybe you knew that already but I only recently discovered that fact and now I'm sharing it. From the wikipedia page:

"Other prehistoric animals, including mosasaurs, ichthyosaurs, pterosaurs, plesiosaurs, and Dimetrodon, while often popularly conceived of as dinosaurs, are not taxonomically classified as dinosaurs. Pterosaurs are distantly related to dinosaurs, being members of the clade Ornithodira. The other groups mentioned are, like dinosaurs, members of Sauropsida (the reptile and bird clade), with the exception of Dimetrodon (which is a synapsid)."

I really enjoy the everchanging Dino-taxonomy. I have a book about Dinosaurs that I read to my kids, and I think most of it would currently be considered wrong.

Unless someone enjoys this subject there's no reason they'd know about the different classifications. I read a lot about this stuff but still need to freshen up my knowledge every time I have a conversation about this for two reasons: the topic is too complex for an amateur and it also tends to be relatively fluid, changing based on new discoveries or theories. Always keep Wikipedia handy :).

If you ever look at different "artist's depiction" drawings about "dinosaurs" you might notice plenty of misconceptions: anatomically incorrect (and impossible) positions, strange mixes of species living in vastly different time periods, animals that aren't actually dinosaurs, etc.

google the constituents of the phrase and build it up from there

birds are dinosaurs and dinosaurs aren't birds

you've reversed the vectored direction of time in your claim

What does a classification have to do with time?

Edit: And what does "vector" add to your sentences?

I think since a vector has a direction, he’s suggesting that the direction of the vector is pointed “the wrong way” with respect to time

What is the difference in meaning between:

  A: "you've reversed the vectored direction of time in your claim" 
  B: "you've reversed the direction of time in your claim"

time has multiple vectors

downvote me if you will but you were the one claiming dinosaurs are birds

I'm not downvoting anything, just trying to figure out what you are trying to say. Can you give names to the multiple vectors of time?

The scientific consensus is that while there are significantly many dimensions to the time space continuum, time makes is only one of those dimensions. Whether or not it is a strictly unidirectional component may be under some debate, but even in quantum mechanics and hypotheses like string theory, there aren’t multiple vectors to time, as it has only one axis and no start or end (that we know of). A vector necessarily has a start, end, and direction.

Perhaps you're thinking of the creatures we saw in Jurassic Park? Yeah, those are somewhat inaccurate. Velociraptor, for example, was the size of a turkey and covered in feathers, with its long tail held upwards, like this:

https://en.m.wikipedia.org/wiki/Velociraptor#/media/File%3AV...

Yeah, basically a weird bird.

The velociraptors in the book, and to a lesser degree the movie, were modelled after Deinonychus.

Michael Crichton thought, correctly, that Velociraptor was a better name.

No doubt. I still preferred the name Raptor to Gecko, too bad it couldn't stay that way.

> Dinosaurs are a type of bird

The opposite. Birds are a type of dinosaurs, but the biggest dinosaurs like Triceratops weren't birds. I'm not wrong, feathers were found in small or middle sized dinosaurs, smaller than the elephant birds.

Capybaras are the largest rodent but not the largest mammal. Elephants birds were the largest bird but not the largest dinosaur.

Moa, from New Zealand, were considerably taller (3.5-4m tall versus 3m tall) but much lighter (230kg versus 500kg).

https://hubpages.com/animals/Comparing-the-Moa-and-The-Eleph...

I'm not a dinosaur expert (but this is hacker news, so...). You know who else wasn't a dinosaur expert? All those people back in the 1800s who lumped theropods, sauropods, and everything else together and called them dinosaurs. So now the definition of dinosaur is, paraphrased from wikipedia, "anything from descended from the most recent ancestor of all the stuff we want to call a dinosaur". I can believe ostriches and elephant birds and small theropods are related. Can you believe the possibly imaginary Brontosaurus and T Rex are related? Is there an intellectually honest reason to lump them together?

Brontosaurus was rebranded as Apatosaurus.

Sort of. Apatosaurus was first, so Brontosaurus lost out as a junior synonym (first to name the things get to name the things, which gives us a silly name meaning "hyrax-like beast" - hyracotherium - for something that's obviously the dawn horse - eohippus)... except that there's very good reason now to believe that they weren't the same species.

Sure, there's an intellectually sound reason for the lumping: There was a long period of earth's history where enormous reptiles were prominent, and almost all but the crocodile family died out. So, it makes sense to have a word for all the age-of-reptiles reptiles we see in fossils. "Dinosaurs" works great. As such, it includes pterosaurs and sea reptiles even.

plesiosaurs and pterosaurs aren't currently considered dinosaurs.

Any DNA?

Might these be recent enough to bring back?

We haven't brought back the passenger pigeon or the Carolina Parakeet yet and both went extinct at the Cincinnati Zoo in the early 20th Century.

Seems to me we'd do better to shut the Cincinnati Zoo...

Both species were doomed to extinction at the point they were housed at the zoo. The passenger pigeon only bred in large flocks and by the time everyone realized they were on the decline, there were no more large flocks.

The zoo at this point were just recording the last survivors for posterity's sake.

> The passenger pigeon only bred in large flocks and by the time everyone realized they were on the decline, there were no more large flocks.

So do penguins, gulls and terns, yet they can be bred in zoos. Also, the big colonies of the passenger pigeon mostly like where a phenomenon of the 19th century (possibly human induced), the effective population size of the species has been shown to have been in the hundreds of thousands range.

Oh, and the Carolina parakeet was bred in zoos, even in Europe. Unfortunately they weren't that consistent back then yet.

Sure, but is that because we cannot do it or because we don't really want to do it? I'd argue that bringing back a the elephant bird would be more exciting (from a 'cool' perspective and scientifically) then bringing back a pigeon or parakeet. There are already dozens (or more?) of species of both of those alive today, with some very close relatives included.

From what I have heard, there are a number of challenges connected here that have to do that birds are usually not a model organism and we therefore lack certain techniques (and knowledge) on how to handle their cells (especially stem cells) in a laboratory (Not surprising since there is not much medical and therefore financial interest in doing so).

The reason why researchers go for those relatively boring species is their boringness: there are closely related species from which you can borrow cells (and eggs) which you than modify. There is no such thing for a huge (another cost factor) animal with no close relative left.

I'd think it would be more exciting in a 'oh the horror, what have we done' kind of perspective. Those things seem scary as hell.

Same, yet I would gladly see it done.

The idea of bringing something old world into current is compelling, definitely morbid in some sense, and primal.

Yeah, not a good mix, but what can I say? This is a want to see happen. I am likely to regret it, but maybe, just maybe it could be a good thing. Somehow.

Yeah but they're working on it:

>The Great Passenger Pigeon Comeback has set ambitious goals to hatch the first generation of new Passenger Pigeons before 2025 and begin trial wild releases in the following 15 years. http://reviverestore.org/projects/the-great-passenger-pigeon...

Yes DNA.

I hope so. https://www.telegraph.co.uk/news/science/science-news/740592...

Even if we can’t clone them now, we should at the very least sequence their dna to digitize what little there is left of it.

The illustration doesn't seem plausible. Their wings would have to look far more bulky to be wide enough to lift their weight.

They couldn’t fly[1].

[1] https://en.wikipedia.org/wiki/Elephant_bird

Oh I see. That explains it.

Why do you think they flew? The top largest birds (by height and mass) alive today do not fly, and could never fly under their own power.

Moa were a massive bird in New Zealand, with some thought to be 4m tall - they didn’t fly. Whilst looking them up I stumbled on the Haast’s Eagle, which hunted Moa. It was huge relative to today’s eagles and hunted Moa. There are accounts from early settlers that may reflect encounters with them.

Thanks for sharing that, I've never heard of the Haast's Eagle.

The ~9ft wing span would be terrifying to see.

> Haast's eagles preyed on large, flightless bird species, including the moa, which was up to fifteen times the weight of the eagle.[9] It is estimated to have attacked at speeds up to 80 km/h (50 mph)

I wonder if these things attacked the early humans that inhabited New Zealand, before they went extinct.

> "The ~9ft wing span would be terrifying to see."

Wow! Looks like large bald eagles can have wing spans of 8ft, so you might get a chance to be nearly (89%?) as terrified :)

> " The largest eagles are from Alaska, where large females may weigh up to 7.5 kg (17 lb) and span 2.44 m (8.0 ft) across the wings."

https://en.wikipedia.org/wiki/Bald_eagle#Description

The Haasts Eagle had a small wingspan relative to it’s size, supposedly as an adaption for forest flight/Moa hunting. So depending on what measure you choose, eg weight, a bald eagle could be less than half the terror.

It’s speculated that they did, and there is a small amount of evidence to support this - cave drawings and word-of-mouth legend among the Māori. https://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&object...

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