AstralTraveller
12-08-2011, 06:29 PM
The first significant finding of the new 'clumped isotope' palaeothermometer has been published.
Dinosaur Body Temperatures Determined from Isotopic (13C-18O) Ordering in Fossil Biominerals Robert A. Eagle, et al. Science 333, 443 (2011); DOI: 10.1126/science.1206196
Abstract: The nature of the physiology and thermal regulation of the nonavian dinosaurs is the subject of debate. Previously, arguments have been made for both endothermic and ectothermic metabolisms on the basis of differing methodologies. We used clumped isotope thermometry to determine body temperatures from the fossilized teeth of large Jurassic sauropods. Our data indicate body temperatures of 36° to 38°C, which are similar to those of most modern mammals. This temperature range is 4° to 7°C lower than predicted by a model that showed scaling of dinosaur body temperature with mass, which could indicate that sauropods had mechanisms to prevent excessively high body temperatures being reached because of their gigantic size.
In my ignorance I assumed that if they were warm they were 'warm blooded' like us. Now it turns out that their body temperature was too low for them to be 'cold blooded', because big animals have a smaller surface area to mass ratio. In an interview one of the authors discussed possible future research methodologies which could help resolve the uncertainty (eg look at smaller related species, look at juveniles of the same species) and made a very convincing case for more research funding. :) Obviously the data set is quite small but that what you get from a new, technically difficult technique. Papers using the type of analysis I do have dozens to perhaps 100s and even 1000s of determinations but back in the 1950s 3 determinations was a paper. The technique will improve, commercial manufacturers will start to develop 'off the shelf' instruments and output will increase. Although in this work addressed a biological question the technique can also be applied to geological samples (eg corals, soil carbonates, possibly speleothems). It will be interesting to follow how our understanding of Earth history is enhanced and altered over the coming decade as more labs come on line around the world.
Dinosaur Body Temperatures Determined from Isotopic (13C-18O) Ordering in Fossil Biominerals Robert A. Eagle, et al. Science 333, 443 (2011); DOI: 10.1126/science.1206196
Abstract: The nature of the physiology and thermal regulation of the nonavian dinosaurs is the subject of debate. Previously, arguments have been made for both endothermic and ectothermic metabolisms on the basis of differing methodologies. We used clumped isotope thermometry to determine body temperatures from the fossilized teeth of large Jurassic sauropods. Our data indicate body temperatures of 36° to 38°C, which are similar to those of most modern mammals. This temperature range is 4° to 7°C lower than predicted by a model that showed scaling of dinosaur body temperature with mass, which could indicate that sauropods had mechanisms to prevent excessively high body temperatures being reached because of their gigantic size.
In my ignorance I assumed that if they were warm they were 'warm blooded' like us. Now it turns out that their body temperature was too low for them to be 'cold blooded', because big animals have a smaller surface area to mass ratio. In an interview one of the authors discussed possible future research methodologies which could help resolve the uncertainty (eg look at smaller related species, look at juveniles of the same species) and made a very convincing case for more research funding. :) Obviously the data set is quite small but that what you get from a new, technically difficult technique. Papers using the type of analysis I do have dozens to perhaps 100s and even 1000s of determinations but back in the 1950s 3 determinations was a paper. The technique will improve, commercial manufacturers will start to develop 'off the shelf' instruments and output will increase. Although in this work addressed a biological question the technique can also be applied to geological samples (eg corals, soil carbonates, possibly speleothems). It will be interesting to follow how our understanding of Earth history is enhanced and altered over the coming decade as more labs come on line around the world.