Sticking a thermometer into a dinosaur (well sort of)

If you’ve been a Jurassic Park fan, watching those huge hulking figures from the Jurassic period in Steven Spielberg movies, you must have wondered whether these dinosaurs were slow-bumbling creatures (because of their gigantic size) in real life, or swift agile animals as Spielberg depicted them.

It’s a question that’s most accurately answered if we knew for sure what the body temperature of those animals were. If they were cold blooded it would mean that they would have to rely on the environment, like reptiles. If they were warm blooded that would have meant that they were nimble like the T rex we’ve seen in the movies.

Now, in research that could well be considered as “sticking a thermometer” in the animal that went extinct 150 million years ago, Caltech scientists, for the first time ever, have measured the body temperature of the dinosaurs. They show that the sauropods of the Jurassic period had body temperatures similar to most modern mammals. The findings are published in June 24 issue of Science _ . _

For the longest while it was believed that nobody could measure the body temperature of dinosaurs simply because it was impossible to do. But by pioneering a new technique which Robert Eagle and his team at the California Institute of Technology call “bullet-proof”, they’ve been able to do so, making a key piece of data available.

Why is this bullet-proof? Because it’s based on the laws of thermodynamics, which, like gravity, are independent of time, context, and setting.

It’s called “clumped isotopic technique”. Researchers measure the concentrations of the rare isotopes carbon-13 and oxygen-18 in bioapatite, a mineral found in teeth and bone. How often these isotopes bond with each other, or “clump”, depends on the temperature. The lower the temperature, the more carbon-13 and oxygen-18 tend to bond in bioapatite. So, measuring the clumping of these isotopes is a direct way to determine the temperature of the environment in which the mineral formed-in this case, inside the dinosaur.

For the study, 11 teeth samples from Tanzania, Wyoming and Oklahoma and belonged to Brachiosaurus brancai and Camarasaurus were analysed_._ They found that the Brachiosaurus had a temperature of about 38.2 degrees Celsius and the Camarasaurus had one of about 35.7 degrees Celsius, warmer than modern and extinct crocodiles and alligators but cooler than birds. The measurements are accurate to within one or two degrees Celsius.

"Nobody has used this approach to look at dinosaur body temperatures before, so our study provides a completely different angle on the longstanding debate about dinosaur physiology," Eagle says.

But if you thought that merely having body temperatures similar to most modern mammals implies that dinosaurs had a warm-blooded metabolism, think again. Because large sauropod dinosaurs were so huge, they could retain their body heat much more efficiently than smaller mammals like humans, say researchers. “If you’re an animal large enough to approximate as a sphere of meat the size of a room, you can’t be cold unless you’re dead,” another researcher John Eiler explains. So even if dinosaurs were “cold blooded” in the sense that they depended on their environments for heat, they would still have warm body temperatures.

“The body temperatures we’ve estimated now, provide a key piece of data that any model of dinosaur physiology has to be able to explain,” says Aradhna Tripati, a co-author who’s an assistant professor at UCLA and visiting researcher in geochemistry at Caltech. “As a result, the data can help scientists test physiological models to explain how these organisms lived.”

Well, if knowing more about them results in better dinosaur movies, along with science even Hollywood would be richer.

And going by some news reports , Spielberg already has dinosaurs back on his mind!