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Dinos not all warm-blooded or cold-blooded, but variable?

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While the warm-blooded vs. cold-blooded argument rages, from New Scientist:

Robert Eagle of the University of California, Los Angeles, and colleagues estimated the body temperature of two types of dinosaur by analysing fossil eggshells. They found that Titanosaurus, a long-necked sauropod around 10 metres long and 13 tonnes in weight, had a body temperature around 38 ̊C, similar to modern mammals.

On the other hand, Oviraptor, a theropod about 2 metres long and 35 kilograms in weight, had a body temperature around 32 ̊C. This is still warmer than crocodiles and their relatives, suggesting that oviraptors generated some heat internally to keep their bodies above the ambient temperature and allow them to be more active. But it also suggests their physiology was not fully warm-blooded, which would require much more energy to maintain.

It would be interesting to see whether consistent warmer body temperatures can be generally associated with more “mammalian” behaviour.

See, for example,

Maiasaura was a large, plant-eating, duck-billed dinosaur. Maiasaura was the first dinosaur that was found alongside its young, eggs, and nests. This suggests that Maiasaura nurtured its young.

On the other hand, ‘gators do too. Early days yet.

The finding is significant because larger animals are better able to retain heat and so would be expected to have higher body temperatures. Previous studies that suggested this was true of dinosaurs don’t necessarily indicate that they generated heat internally like mammals. More.

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3 Replies to “Dinos not all warm-blooded or cold-blooded, but variable?

  1. 1
    Mung says:

    ok, so they had blood.

    And you can make a tree of warm blood and cold blood as branches on the tree of blood.

    Therefore evolution is true.

  2. 2
    Robert Byers says:

    Hood thread. The bigger error is saying there was ever a cold/warm blooded division in nature. If a creature needs it they got it. there are no such divisions, i say, of dinos or reptiles or mammals. its just traits grouping gone crazy.
    Its predictable from this point of view to find ‘dinos’ having blood styles as needed. They are not reptiles or there are no reptiles. just kinds.
    Easily sone “snnos” were as warm blooded as me or cold blooded as crocs.
    its a error to classify them by these traits. its not related to common descent claims. Just trait grouping and no smarter then that.
    AHA. finally they found a big enough difference to question presumptions.

  3. 3
    salamander says:

    The results may well be explained by gigantothermy. Gigantothermy (also called ectothermic homeothermy) is a phenomenon, where large, heavy bodied ectothermic animals are more able to maintain a nearly constant, relatively high body temperature than smaller animals by virtue of their smaller surface area to volume ratio.”

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