I think the argument has been mostly settled in favor of the "lukewarm-blooded" theory, but it'd still be interesting to see if anyone has any dissenting opinions.

  • Bluegrass_Buddhist [none/use name]
    hexagon
    ·
    3 years ago

    Yeah but there are plenty of big archosaurs that are ectothermic. Not that any of them approach the size of a ceratopsian, but the proof of concept is there. Look at some alligators in the U.S., they make it through occasionally-freezing winters.

    If they can be ectothermic, I feel like something 3x their size could still get by on being mesothermic.

    • coeliacmccarthy [he/him]
      ·
      edit-2
      3 years ago

      Look at some alligators in the U.S., they make it through occasionally-freezing winters.

      Yeah but late cretaceous arctic winters got colder than winters in the range of alligators. There's no gators in Montana today and a polar cretaceous winter would have been similarly cold. The same arctic site that I'm thinking of re:ceratopsians specifically turned up zero remains of reptiles or amphibians despite them having sieved and sorted all microfossils

      • Bluegrass_Buddhist [none/use name]
        hexagon
        ·
        edit-2
        3 years ago

        a polar cretaceous winter would have been similarly cold

        For real? I don't know much about cretacious climates but I thought the era was generally warmer than the quaternary. Like no-ice-at-the-poles warm. Happy to be wrong about this, that was just my impression.

        • coeliacmccarthy [he/him]
          ·
          edit-2
          3 years ago

          no permanent ice at the poles, correct; but sea ice in winter wasn't out of the question IMO. It was a lot warmer but that still meant a cool-temperate continental climate like, say, continental eastern europe or the northern Rockies

          • Bluegrass_Buddhist [none/use name]
            hexagon
            ·
            3 years ago

            Hmm... Ok. Idk. The thing that put me in the lukewarm-blood camp was a paper I read about dinosaur growth rates (specifically therapods and sauropods, I think?). The argument was they grew in a way that was too seasonally-dependant to be warm-blooded, but too quickly to be truly cold-blooded. Or something along those lines.