A new study published in Nature challenges the common belief that dinosaurs were cold blooded. This belief was mainly based on the fact that dinosaurs’ bones presented ‘lines of arrested growth’, or LAGs, which are marks that show periods of suspended growth, also found in reptiles and amphibians. Now researchers have found these marks on the bones of 41 modern mammals.
‘These lines of arrested growth have been used a lot in dinosaurs, but nobody has ever had a really deep look at mammals,’ says co-author Dr Meike Koehler, of the Catalan Institute of Palaeontology in Barcelona. ‘This is the first time that you can say that Lags do not say anything about warm- or cold-bloodedness.’
But this is not the only indicator that questions the cold-blooded theory. They also found that ‘dinosaurs not only grew very fast but this growth was sustained by a very high metabolic rate, indicating warm-bloodedness,’ says Dr Koehler.
Meike Köhler, Nekane Marín-Moratalla, Xavier Jordana, & Ronny Aanes (2012). Seasonal bone growth and physiology in endotherms shed light on dinosaur physiology Nature DOI: 10.1038/nature11264
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