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 Despite popular belief that all dinosaurs
were slow and cold-blooded, researchers have found that
at least some were active
and warm-blooded. Researcher Roger Seymour of the University of Adelaide
in South Australia and his colleagues began measuring
the size of the nutrient foramen hole, which
is the hole that passes through each bone where the artery and vein supplies blood and oxygen to the bone cells. Past research suggests that the size of
the holes in human bones is related to the maximum rate that a person can be
active during exercise.
So, researchers have applied the same concept to dinosaurs by first
measuring the sizes of the nutrient foramen holes of living mammals and reptiles. Then, they compared these holes to the
metabolic rates and found
that the sizes of the holes were related closely to the metabolic
rates during peak movement.
Finally, they measured the holes in 10
species of dinosaurs from
5 different groups, including carnivores (meat-eaters)
and herbivores (plant-eaters)
and compared it to their data. The results suggest that dinosaurs
were even more active than modern-day mammals, which could mean that
dinosaurs were warm-blooded, as well as highly active.
Another recent study supports this theory as well. Last month,
researchers at Caltech University in California, U.S., tested the
teeth of two different plant-eating dinosaur species. By measuring
the composition of the teeth,
researchers could estimate the temperature of the dinosaur.
They found that the dinosaurs had around the same temperature as humans.
The Brachiosaurus species had a temperature of about 38.2 degrees Celsius and the Camarasaurus
species was about 35.7 degrees Celsius. The commonly accepted average core body temperature of
humans is 37.0 degrees Celsius.
These new studies seem to support the notion that dinosaurs were
not cold-blooded like today’s lizards and reptiles. Additionally, their much
larger body size could have been warmed up just from the heat of their
metabolism. Giant herbivore dinosaurs may have stayed in the shade
or near water to cool down when they reached
their full, adult size. |
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