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.

  • coeliacmccarthy [he/him]
    ·
    3 years ago

    it's pretty well established that all theropods were warmblooded imo

    I guess there's still a case to be made for some non-theropods being lukewarm-blooded but I wouldn't bother at this point, I mean ceratopsians were living through winter in cool-temperate polar climates and if they weren't warmblooded than no dinosaurs were

    • Bluegrass_Buddhist [none/use name]
      ·
      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]
        ·
        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]
          ·
          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]
            ·
            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]
              ·
              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.