A final test for the theory of warm-blooded dinosaurs is what they ate. A warm-blooded animal consumes ten times as many calories per year as a cold-blooded creature of the same size. If a seven-hundred-pound Allosaurus were producing metabolic heat every minute of its life at a rate as high as a modern seven-hundred-pound bear, its meat consumption would have to be enormous. (life size dinosaur)But if that allosaur operated like the traditional cold-blooded dinosaur, then it could bask in the warm Jurassic sunshine, soaking up the solar calories until it reached its preferred body temperature without squandering energy derived from food. Which hypothesis comes closer to the truth?
By 1970, my studies of dinosaur limbs had already persuaded me that dinosaurs were designed for high levels of locomotor activity.(animatronic dinosaur) I had also suspected that the dinosaurs’ metabolism more closely resembled a giant bird’s than a giant tortoise’s. How else could they have suppressed the evolution of mammals for more than a hundred million years? But how could anyone measure metabolism in a fossil? It seemed a completely forlorn prospect.
Sometime in 1970, Elwyn Simons, professor of primate paleontology at Yale (now a member of the National Academy of Science), provided me with an invaluable insight. He was discussing the fossil mammals he had been excavating for a decade in Wyoming, in Egypt, and in India’s Siwalik Hills. He observed that numerous large predators were never found in the fossil record; they were always rare.(realistic dinosaur costume) This was because the big meateater subsisted at the very top of the ecological pyramid. Its food had to come from the plant-eaters below. And it took roughly a hundred zebra to maintain the supply of meat for one lioness and her cubs. I realized his remarks about the scarcity of predators would apply perfectly to dinosaurs. If predatory dinosaurs required as much meat per week as warm-blooded mammals, then they would have to be rare. The predatorprey relationship might well serve therefore for the calorimeter I was looking for.