Slashdot Mirror


Birds Had To Relearn Flight After Meteor Wiped Out Dinosaurs, Fossil Records Suggest (theguardian.com)

An anonymous reader quotes a report from The Guardian: Birds had to rediscover flight after the meteor strike that killed off the dinosaurs, scientists say. The cataclysm 66 million years ago not only wiped out Tyrannosaurus rex and ground-dwelling dinosaur species, but also flying birds, a detailed survey of the fossil record suggests. As forests burned around the world, the only birds to survive were flightless emu-like species that lived on the ground. The six to nine-mile-wide meteor struck the Earth off the coast of Mexico, releasing a million times more energy than the largest atomic bomb. Hot debris raining from the sky is thought to have triggered global wildfires immediately after the impact. It took hundreds or even thousands of years for the world's forests of palms and pines to recover. Fossil records from New Zealand, Japan, Europe and North America, all show evidence of mass deforestation. They also reveal that birds surviving the end of the Cretaceous period had long sturdy legs made for living on the ground. They resembled emus and kiwis, said the researchers whose findings are reported in the journal Current Biology.

60 comments

  1. Puzzling by ztexas · · Score: 2

    Never understood how birds are the only remaining dinosaurs... wonder what made dinos so vulnerable to this event, where many other large species (crocs, turtles, fish, etc) survive to this day. One might think that some small dinosaurs, or aquatic/marine species would have found a niche on some continent. Population bottleneck, I guess. Imagine if no dinosaurs at all had survived... maybe we'd have a lot more large insects and bats species filling the skies.

    1. Re:Puzzling by Anonymous Coward · · Score: 1

      Never understood how birds are the only remaining dinosaurs...

      Likely nothing more than dumb luck - a few tens of a handful of species (or maybe even less) is probably all that survived.

    2. Re:Puzzling by Anonymous Coward · · Score: 0

      Never understood how birds are the only remaining dinosaurs...

      Define a dinosaur.

    3. Re:Puzzling by TeknoHog · · Score: 3, Informative

      Good point, but there's another issue with large insects; they need a higher concentration of oxygen in the air than what we currently have. Insects have no lungs or blood, they breathe directly into every cell, so they are more sensitive to this. O2 concentration also affects other species in different ways, many things will simply burn out with too much of it.

      --
      Escher was the first MC and Giger invented the HR department.
    4. Re:Puzzling by Anonymous Coward · · Score: 2, Interesting

      According to some estimates that fallen debris may have heated the air to the temperature of a pizza oven. The ground dwelling birds and small mammals would have needed only 30-40 cm of ground to protect themselves from it. Also, animals capable of diving would have access to food supplies that had been protected from the heat and the resulting fires.
        Crocodiles and turtles can survive longer periods without food than the bigger, presumably warm blooded dinosaurs and those aquatic species may have been vulnerable as their food chains were altered by the changing climate and marine chemistry from the impact and increasing pressure from the fish.

    5. Re:Puzzling by TheABomb · · Score: 1

      The last common ancestor of Triceratops horridus, Passer domesticus, Diplodocus carnegii, and all of its descendants.

      --
      MSIE: The world's most standards-complaint web browser.
    6. Re:Puzzling by pubwvj · · Score: 1

      I like your little quote 'The opposite of "moron" is "lesson"' but there is a third option, 'the opposite of "Anon" is "moron"'.

    7. Re:Puzzling by Anonymous Coward · · Score: 0

      There are plenty of reptiles that would disagree with your assessment.

    8. Re:Puzzling by knorthern+knight · · Score: 3, Informative

      > Never understood how birds are the only remaining dinosaurs... wonder what
      > made dinos so vulnerable to this event, where many other large species (crocs,
      > turtles, fish, etc) survive to this day. One might think that some ***SMALL DINOSAURS***,
      > or aquatic/marine species would have found a niche on some continent.

      By "dinos", I assume you mean umpteen ton monstrosities. Most, if not all Cretaceous dinosaurs (even the large monstrosities) are now believd to have had feathers to maintain body tempearures. Birds == dinosaurs. It's not just the newer finds. Careful re-examination shows compsognathus == archeopteryx.

      The big rock hits earth 65,000,000 years ago, and throws up a shower of debris out of the atmosphere. As the debris rains down all over planet earth, atmospheric friction heats up the incoming debris to several hundred degrees. This hail of red hot stones kills most large animals, and set most forests on fire.

      Smaller particles remain in the atmosphere for a few years, blocking a lot of sunlight, and a "nuclear winter" happens. The bottom of the ecosystem (plants) gets greatly reduced. Forget large trees; you're down to hardy ferns Any large vegetarians that survived the initial "rain of fire" die of starvation, since they need a lot of plant matter every day to survive, let alone grow. When the remaining large vegetarians starve to death, there's no food for the large carnivores, so they starve to death.

      Re your question about "small dinosaurs"... yes, some did survive. I repeat... birds == dinosaurs. The ones that survived were in the same size range as small mammals that survived. They occupied similar niches, and may have occupied burrows. If they couldn't dig burrows, they could chase out the small mammals who originally dug them. So when the big rock hit, small mammals and small dinosaurs (i.e. birds) that lived in burrows would've survived the initial "rain of fire". Burrows would be crucial for birds, because they lay eggs, rather than bearing their young via pregnancy.

      Small dinosaurs ("birds") would compete in the same niches as small mammals, and we know that small mammals survived. Surviving birds at that time would probably be omnivores. They could eat small plants, with the occasional addition of meat in the form of insects and small mammals and even other birds.

      --

      I'm not repeating myself
      I'm an X window user; I'm an ex-Windows user
    9. Re:Puzzling by TeknoHog · · Score: 1

      It's originally a play on the words more vs. less. I like having multiple levels of meaning.

      --
      Escher was the first MC and Giger invented the HR department.
    10. Re: Puzzling by Anonymous Coward · · Score: 0

      Note that reptiles are cold-blooded, dinosaurs were hot-blooded (at least that's the current theory since first of all they discovered that dinosaurs had feathers which only makes sense for hot-blooded animals, and secondly birds are their decendants and share this trait. )

    11. Re: Puzzling by TheRaven64 · · Score: 1
      [ From memory of a visit to a dinosaur museum as a small child, so probably wrong: ]

      Dinosaurs also had a different arrangement of scales to modern lizards (overlapping vs tessellated) and had legs pointing straight downwards, whereas surviving lizards have their legs attached at the sides (I don't know how true this is of other reptiles - I am not a biologist).

      Given their skeletal structure and the theory that they were warm blooded, I wouldn't be surprised if cows were closer relatives of dinosaurs than most reptiles.

      --
      I am TheRaven on Soylent News
    12. Re:Puzzling by iggymanz · · Score: 1

      how large is "large"? we still have 24" walking sticks and foot-wide butterflies and 7" titan beetles. wasn't the largest ever with two foot wingspan?

    13. Re: Puzzling by dryeo · · Score: 1

      The Arcosaurs (ancestors of all reptiles) and Therapsids (ancestors of all mammals and the like) split off a long time back. The closest living relatives of Dinosaurs, including the birds are actually the crocodilians, which have advanced features like a 4 chambered heart and apparently were warm blooded and then reverted to cold blooded.
      https://en.wikipedia.org/wiki/...
      https://en.wikipedia.org/wiki/...

      --
      https://en.wikipedia.org/wiki/Inverted_totalitarianism
  2. Alphas by Tablizer · · Score: 4, Interesting

    It's interesting that flightless birds had a pretty strong reign during the early recovery phases. They were often the dominant hunters of the time.

    It's often speculated that mammals eventually replaced those giant flightless birds as the alpha hunters not because mammals are more powerful than big birds, but rather because mammals learned to better leverage pack hunting: social coordination. Otherwise, this era would have resembled Dinosaurs 2.0, with 40-foot birds: Sqaaawwwk!! BOOOM

    1. Re:Alphas by CrimsonAvenger · · Score: 1

      It's interesting that flightless birds had a pretty strong reign during the early recovery phases.

      By "interesting", I assume you mean "unsurprising", eh? It's not like the non-avian dinosaurs (flightless birds) didn't have a strong reign 200-odd megayears leading up to the Big Falling Rock....

      --

      "I do not agree with what you say, but I will defend to the death your right to say it"
    2. Re:Alphas by BeauHD++(.)+(349) · · Score: 1

      Lighten up, this is a place for all discussion

    3. Re:Alphas by TigerPlish · · Score: 1

      with 40-foot birds:

      "North Perry Tower, Bonanza 1701 Sierra Tango, request an interceptor assist from the USAF, we seem to be gripped in the talons of a bird bigger than my plane..."

      "01 Sierra Papa, North Perry Tower, do you have any firearms with you?"

      "That's a negative, North Perry, we really need that assist right now, the claws are coming in through the roof..."

      *crunch* *crumple* *Burrrrp*

      Beechraft! More Taste, More Filling! *squaaaaak!*

      --
      The "Civilized World" jumped the shark ca. 1973.
    4. Re:Alphas by dryeo · · Score: 1

      Yes, and before that the Therapsids (our ancestors) had a good run as the dominant type of animal, until the Permian–Triassic extinction event wiped most of them (and most everything else) out and allowed the accession of the Dinosaurs.
      The birds did recover fast before being passed by mammals as the apex hunters.

      --
      https://en.wikipedia.org/wiki/Inverted_totalitarianism
  3. Effects by burtosis · · Score: 3, Interesting

    Not suprising as it is also thought to have created a tsunami 330 feet tall along the coasts of Texas and flordia, but as high as 2.9 miles in deep ocean. It is 12 miles deep and 93 miles in diameter. It's pretty amazing as you can date the effects in many areas by the layer of material it spread over the whole world. Good thing these giant impacts are extremely rare because if we spot it late there is jack squat we could do.

    1. Re:Effects by clotaire · · Score: 2

      if we spot it late there is jack squat we could do.

      Can we do anything if we spot it early ?

    2. Re:Effects by Calydor · · Score: 1

      Duck and cover.

      --
      -=This sig has nothing to do with my comment. Move along now=-
    3. Re: Effects by Anonymous Coward · · Score: 0

      Considering it can take hours to cross the Potomac on any given daily commute in the Washington Metro region, the odds of evacuating in an emergency here, or any other large city, seem pretty slight indeed!

      Better to hunker down and crank up the tunes. My disaster playlist:
      REMâ(TM)s âoeItâ(TM)s the end of the worldâ
      Men Without Hatâ(TM)s âoePop Goes the Worldâ
      The Doors âoeThe Endâ
      And of course Fishboneâ(TM)s âoeParty at Ground Zeroâ

    4. Re: Effects by Zorpheus · · Score: 1

      Altering the course of the meteor? It doesn't need much change of its course if it is detected early enough.

    5. Re: Effects by burtosis · · Score: 1

      Altering the course of the meteor? It doesn't need much change of its course if it is detected early enough.

      Yep. If we have a few decades warning it wouldn't be that hard. Simply impacting it with a small probe could even be enough if it's solid.

    6. Re: Effects by Kickasso · · Score: 1

      We cannot predict orbits with this kind of precision. We wouldn't know whether it's on a collision path a few decades before a potential impact. A small change in its course we would be able to achieve would leave us just as uncertain.

    7. Re: Effects by Anonymous Coward · · Score: 0

      You're a bad person and you should feel bad.

  4. in more ways than one by eaglesrule · · Score: 2

    Considering how the flight of the hummingbird more resembles that of an insect than it does of other birds.

  5. Flight is lost if predators no longer exist by Anonymous Coward · · Score: 1

    I am very very likely completely wrong, but I would speculate birds - flying birds - survived, and rapidly lost their power of flight, because it was no longer needed, because their predators were all dead.

    1. Re:Flight is lost if predators no longer exist by TigerPlish · · Score: 1

      I would speculate birds - flying birds - survived, and rapidly lost their power of flight, because it was no longer needed, because their predators were all dead.

      The romantic in me would like to think that even a bird, non-sentient as it is, feels the beauty in flight.

      --
      The "Civilized World" jumped the shark ca. 1973.
    2. Re:Flight is lost if predators no longer exist by careysub · · Score: 3, Informative

      I am very very likely completely wrong, but I would speculate birds - flying birds - survived, and rapidly lost their power of flight, because it was no longer needed, because their predators were all dead.

      That is very likely to have happened in any area that really lost all or most ground predators. It is the reason that flightless birds evolved in New Zealand and islands around the world. Although flightless birds have evolved on continents as well, their distribution on islands is notable, a large fraction of all flightless species hale from predator-free islands.

      --
      Starships were meant to fly, Hands up and touch the sky - Nicky Minaj
    3. Re:Flight is lost if predators no longer exist by Anonymous Coward · · Score: 0

      The romantic in me would like to think that even a bird, non-sentient as it is, feels the beauty in flight.

      By definition, if something is non-sentient then it can't feel anything. I think it's pretty obvious that birds are sentient though.

    4. Re: Flight is lost if predators no longer exist by Anonymous Coward · · Score: 0

      What definition are you using? As a non-native English speaker, my impression was that sentient referred to an intelligent consciousness (which we in humans associate with our neo-cortex, but its clear that e.g. elephants, dolphins, and chimps have many of the same traits), that makes you rationally aware of why you do things. While non-sentient life would be driven primarily by instincts in what we call the subconscious, but nevertheless experience emotions and feelings, since that is a part of the subconscious.

    5. Re:Flight is lost if predators no longer exist by Anonymous Coward · · Score: 0

      More likely flighted birds died off with the forests the meteor burned off the face of the earth and that took 100s or 1000s yr to regrow. The fossil record shows an abrupt end to flight.

      So in the case of somewhere like NZ, isolated before the extinction event (80m/66m), after the event, the birds remained flightless, mostly.

      As to no predators? I introduce you to Haast's Eagle.

    6. Re:Flight is lost if predators no longer exist by Anonymous Coward · · Score: 0

      > More likely flighted birds died off with the forests the meteor
      > burned off the face of the earth and that took 100s or 1000s yr
      > to regrow. The fossil record shows an abrupt end to flight.

      Although I may be wrong, I think "abrupt" in fossil record terms is an enourmously long period of time in evolutionary terms. Far more time than is needed for a species to evolve away from flight. Perhaps the abrupt end in the fossil record might be a mass evolved loss of flight.

      The fossil record is also much more fragmentory and less effective than I think people realize.

      I've read the oceans might have been much less affected by the event. It's possible that flight remained, and birds fed mainly on fish, and spent very little time on land, and so again, disappeared from the fossil record, as their lifestyle now strongly discouraged fossil formation, by living close to shore-lines or on islands.

      > So in the case of somewhere like NZ, isolated before the
      > extinction event (80m/66m), after the event, the birds remained
      > flightless, mostly.

      I'm not sure about this.

      I may be wrong, but I think when NZ broke away from Gondwanaland, it carried a representative population with it - plenty of dinosaurs, early mammals, etc.

      When the event occurred, NZ had the same experience as everywhere else : mass extinctions. Question is, did only flightless birds survive? that seems an odd proposition to me - why would flightless birds be in a significantly different position to any other land based creature?

      But if they could fly, they could hunt at sea, and survive. After that, and all predators gone, the ecosystem on land recovered, and they lost flight.

      No land based predators ever evolved on NZ, possibly a stable system of some kind, but I would imagine there was a constant flow of new airborne species flying in from outside.

      So NZ kept up-to-date, as it were.

      > As to no predators? I introduce you to Haast's Eagle.

      I'm not sure avian predators change things. I suspect for the prey, loosing flight - which is also to say, becoming more agile and capable on land - may provide protective advantages. For the predator, if their prey are increasingly land based, and given how expensive flight is, probably they also begin to lose flight.

    7. Re: Flight is lost if predators no longer exist by Anonymous Coward · · Score: 0

      "Able to perceive or feel"

      https://en.oxforddictionaries.com/definition/sentient

    8. Re: Flight is lost if predators no longer exist by Anonymous Coward · · Score: 0

      That wasn't due to no predators, it was due to a lack of creatures filing the "ground dwelling tiny animal" place on the island, making it advantageous to stay on the ground vs. Compete with tree dwelling birds for resources.

      That's why those islands still have flying birds.

      How hard is that to grasp?

    9. Re:Flight is lost if predators no longer exist by Anonymous Coward · · Score: 0

      Plenty of birds are smart enough to understand joy and aesthetic. Consider corvids like the crow and raven. They're known to practice bizarre aerobatics seemingly just for fun, or do surprising things like slide down a snowy roof on an improvised sled. I'm sure they take it for granted, but they certainly derive pleasure from flight.

  6. Sea birds by Anonymous Coward · · Score: 0

    What about sea birds who dwell on rocky cliffs? They don't need trees.

  7. Plenty of flying birds do not live in trees by Anonymous Coward · · Score: 0

    Plenty of flying birds do not live in trees

  8. But before they could learn to fly by 93+Escort+Wagon · · Score: 1

    They had to learn how to fall.

    --
    #DeleteChrome
    1. Re: But before they could learn to fly by Anonymous Coward · · Score: 0

      There is an art to flying, or rather a knack. The knack lies in learning how to throw yourself at the ground and miss. ... Clearly, it is this second part, the missing, that presents the difficulties. - Hitchhikers Guide to the Galaxy

  9. Non-arboreal != flightless by erice · · Score: 4, Informative

    Both the article and the summary but not the actual paper make the claim that the only birds to survive were flightless. The actual paper talks about the demise of arboreal species. This makes sense as it is difficult for a tree-dwelling species to survive if the trees have gone. It does not follow that the survivors were necessarily flightless. Today most ground-dwelling species retain the ability to fly. And many of these have long, sturdy legs. Given that these kinds of birds don't tend to fly much, it is reasonable that many of these would adapt to a purely flightless lifestyle in the absence of predation. It does not follow that birds had to learn to fly all over again. Even if it took hundreds to thousands of years for the forests to recover, there should still be populations that retain flight ability allowing them to radiate back into the trees quickly.

    1. Re:Non-arboreal != flightless by Anonymous Coward · · Score: 1

      erice pointed out:

      Both the article and the summary but not the actual paper make the claim that the only birds to survive were flightless. The actual paper talks about the demise of arboreal species. This makes sense as it is difficult for a tree-dwelling species to survive if the trees have gone. It does not follow that the survivors were necessarily flightless. Today most ground-dwelling species retain the ability to fly. And many of these have long, sturdy legs. Given that these kinds of birds don't tend to fly much, it is reasonable that many of these would adapt to a purely flightless lifestyle in the absence of predation. It does not follow that birds had to learn to fly all over again. Even if it took hundreds to thousands of years for the forests to recover, there should still be populations that retain flight ability allowing them to radiate back into the trees quickly.

      If you were not already modded to +5 Informative, I'd've given you +1 Insightful for the above observation.

      The Guardian's very brief summary was obviously written by a journalist who did not understand the paper on which he was reporting. Like you, I actually read the thing. As is typical of scientific papers on paleontological hypotheses, it's pretty careful about constraining its conclusions to what the actual evidence suggests. It was The Guardian's reporter who jumped to the conclusion that because "arboreal species" were apparently made extinct by the Chixiculub bolide impact meant only flightless birds survived. Had he lived in the country, in areas where quail and other ground-nesting birds are common, he would have learned otherwise.

      But, hey, what can you expect from city folk with no scientific background ... ?

      (Posting as AC only so as not to undo prior upmods in this thread.)

      --

      Check out my novel ...

  10. Chickens by fred911 · · Score: 1

    They didn't learn too well..

    --
    09 F9 11 02 9D 74 E3 5B - D8 41 56 C5 63 56 88 C0 45 5F E1 04 22 CA 29 C4 93 3F 95 05 2B 79 2A B2
    1. Re:Chickens by iggymanz · · Score: 3, Informative

      chickens that aren't obese corn fed blubber balls can fly

      https://www.youtube.com/watch?...

  11. not in Arizona (nt) by xxxLCxxx · · Score: 1

    nuttin

  12. Guardian Editor: Gone to Lunch by Anonymous Coward · · Score: 0

    Meteors don't strike the ground - meteorites do.

  13. These scientists beg to differ by Anonymous Coward · · Score: 0

    Fire and brimstone falling down from the sky!

    Earthquakes! Volcanos! The dead rising from the grave! Human sacrifice!

    I believe the Birds learning to fly again was a deleted scene

  14. Flightless birds have one big disadvantage by shoor · · Score: 1

    Flightless birds never evolved a way to really repurpose their front limbs. Ostriches, emus, kiwis all have vestigal wings with limited use if any. Other land vertebrates, whose front limbs hadn't become so highly specialized yet, could gradually evolve them along different paths to become good tree climbers (everything from chameleons to monkeys), or learn to dig burrows (moles), to be good swimmers (OK, penguins also managed to make good use of their front limbs in that regard, but I'm not sure if the ancestors of penguins were flightless.) have claws for helping to hold onto prey while killing it, and so on.

    --
    In theory, theory and practice are the same; in practice they're different. (Yogi Berra & A. Einstein)
    1. Re:Flightless birds have one big disadvantage by dryeo · · Score: 1

      The terror birds repurposed their wings as daggers. They were pretty scary.
      Hmm, wiki doesn't mention the wings, so perhaps I'm wrong, still a 10 ft bird that can run fast, extend its neck when striking with its large head and hooked large beak would have been scary.
      https://en.wikipedia.org/wiki/...

      --
      https://en.wikipedia.org/wiki/Inverted_totalitarianism
  15. Thousands of years? by Anonymous Coward · · Score: 0

    Another puzzling point of TFA is as follow--
    > ... It took hundreds or even thousands of years for the world's forests of palms and pines to recover ...

    Most plants don't need thousands of years to grow.

    Most forests do not need thousands of years back.

    Forest in the Yellow Stone Park which had been devastated by wild fires took 2 decades or so to rejuvenate. Ditto for many wooded areas around the world (Australia, Canada, Russia).

    I believe the authors of TFA have over exaggerated on many of points in the TFA, which makes it untrustworthy as a serious scientific article.

    1. Re: Thousands of years? by Anonymous Coward · · Score: 0

      Perhaps the article is clear in it's meaning, and it is you that does not understand the scale of 'catastrophic'? Anyone with a highschool level education of ecological systems should be able to understand the context.

    2. Re:Thousands of years? by Anonymous Coward · · Score: 0

      You of course assume that new trees started growing instantly and simultaneously all over the world. You don't happen to be a current employee at the EPA by any chance?

  16. Ooh ooh I can make up scientific claims too! by Anonymous Coward · · Score: 0

    Most likely dodo birds were smarter than humans new research claims!

    Early man loved McDonaldâ(TM)s more than Burger King!

    All Fish used to have lasers for eyeballs!

    This is great! Iâ(TM)m obviously contributing so much to society with stupid and wildly improbable as well as spectacularly speculative âoescienceâ

  17. Claim of reforestration time make sense? by fygment · · Score: 1

    "hundreds or thousands" of years to recover? what does recover mean? it takes forests decades to recover if that. it would take hundreds or thousands of years only for forests to recover to the exact state they were in when the fire occurred but that's a pretty nonsensical definition because some forests would _never_ recover. words, the cause of and cure to so much misunderstanding.

    --
    "Consensus" in science is _always_ a political construct.