[HN Gopher] Dinosaurs: How long did they live? (2009)
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       Dinosaurs: How long did they live? (2009)
        
       Author : clouddrover
       Score  : 25 points
       Date   : 2022-06-05 11:56 UTC (1 days ago)
        
 (HTM) web link (www.theguardian.com)
 (TXT) w3m dump (www.theguardian.com)
        
       | mistrial9 wrote:
       | Q. is it scientific consensus that modern birds "are dinosaurs" ?
        
         | sigg3 wrote:
         | Just saw this video on Reddit: 72 million year old dinosaur egg
         | found in China with embryo intact
         | 
         | https://v.redd.it/vn0qwpongl391
         | 
         | One of the coolest discoveries IMO is the tucking position,
         | which is usually attributed more or less exclusively to birds.
        
         | prerok wrote:
         | Short answer: yes :)
         | 
         | https://en.m.wikipedia.org/wiki/Origin_of_birds
        
         | exo-pla-net wrote:
         | Yes, birds are feathered theropod dinosaurs.
        
           | jonny_eh wrote:
           | If I'm not mistaken, we're still not sure how many species of
           | dinosaurs were feathered. But it's likely at least many
           | (all?) theropods (e.g. velociraptor, T-Rex) were.
        
             | adrian_b wrote:
             | There was a paper published this year about feathers
             | identified in a fossil pterosaur.
             | 
             | Previously it was believed that the pterosaurs were covered
             | by some kind of hair (i.e. unbranched), not by feathers.
             | 
             | (Most depictions of pterosaurs in movies are probably
             | wrong, because they do not show even the hair, whose
             | existence has been known for many years, much less that the
             | hair was in fact some kind of bird-like down, which is a
             | very recent discovery.)
             | 
             | The pterosaurs are not dinosaurs, but they are related to
             | dinosaurs, probably closer to them than to crocodiles.
             | 
             | If it is true that the pterosaurs also had feathers, it is
             | unlikely that feathers have evolved twice, as they are much
             | more complex than hair.
             | 
             | In that case, the ancestor of all dinosaurs already had
             | feathers. We know that there are many kinds of large
             | dinosaurs, especially most of the large herbivores, which
             | did not have feathers. If the common ancestor had feathers,
             | then all the large featherless dinosaurs have lost their
             | feathers, like the elephants and the rhinoceroses, which
             | have lost their hair, presumably for improved cooling.
        
               | mistrial9 wrote:
               | not a specialist here, my first reaction is .. feathers
               | are quite insulating.. so, not good for hot climates.
               | Flying means that the creature is in wind all day, cool
               | climate or not.. So put that together, I suspect that
               | lots of the large reptiles just had to be in warm
               | climates, and did not use insulating features each day.
               | 
               | useful and interesting to see that everyone here is
               | saying "yes" to the birds question
        
               | jonny_eh wrote:
               | Calling dinosaurs reptiles is fairly wrong at this point,
               | since a dinosaurs were warm blooded, and being cold
               | blooded is a defining characteristic of being a reptile.
               | This does raise the question if it's worth considering
               | birds and dinosaurs as different groups.
        
               | mistrial9 wrote:
               | > dinosaurs were warm blooded
               | 
               | hm? pointers please.. if they lay eggs then that is
               | "reptile" no? I don't claim to know, I am asking..
        
               | jonny_eh wrote:
               | https://earth.yale.edu/news/were-dinosaurs-warm-blooded-
               | thei...
               | 
               | Birds lay eggs and are definitely warm blooded. Not to
               | mention the odd mammal that lays eggs like the platypus.
        
             | webwielder2 wrote:
             | The new dinosaurs documentary on Apple TV+ portrays
             | velociraptor as feathered, but T-Rex still looks like an
             | old school "terrible lizard"
        
               | adrian_b wrote:
               | There are chances that this might be correct.
               | 
               | It is likely that a dinosaur of the size of T-Rex would
               | overheat if covered with feathers.
               | 
               | It is still possible that T-Rex had feathers when very
               | young and then lost them when growing large enough.
        
               | jonny_eh wrote:
               | Or had them ornamentally, like we (well, not me) have
               | hair on the tops of our heads.
        
       | andsoitis wrote:
       | How long do birds live: https://abcbirds.org/blog21/bird-
       | longevity/
        
       | exo-pla-net wrote:
       | For those who just want the answer: 70-80 years for a large
       | herbivore, and 20-30 for a large carnivore.
        
         | [deleted]
        
       | infradig wrote:
       | I don't know how long they lived, but according to the Jurassic
       | film franchise they must grow very quickly.
        
         | bluedino wrote:
         | FWIW an Ostrich reaches adult size in 18 months
        
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