Finbacks provided the ideal fossil test case for the predator toprey concept. In the first place, they were unquestionably cold-blooded. Their anatomy was still on a very primitive level, more primitive in most aspects of their limb and backbone than today’s lizards. (life size dinosaur)Even the structure of their bone appeared emphatically cold-blooded under the microscope. The canals left by blood vessels were few and far between, proving that metabolic activity proceeded at a very modest pace.
In the second place, the finbacks were large early species grew to the size of wolves and leopards, forty to eighty pounds, and later species were larger still, up to two hundred pounds or more, the size of the average lioness. (Realsitic dinosaur costume)These big finbacks seemed large enough and well enough armed to deal with any animal in their ecosystem. Their heads were proportionately large, and armed with strong killing teeth in front and razor-sharp rear teeth for cutting up even the largest carcass. Moreover, these creatures are found in nearly every fossil habitat: swamps, lakes, streams, swampy floodplains, driedout floodplains. With such ecological diversity, it was possible to determine whether the predator-to-prey ratio changed from habitat to habitat. And finally, all the species of prey available to them were incontestably cold-blooded as well.
By the time I had fixed upon the finbacks as a key test for my method, I left Yale for Harvard. There I met Al Romer, the world’s leading expert on finbacks. He was even fond of them especially of one genus, Dimetrodon. (dinosaur factory)On his office door he kept a cartoon that featured Dimetrodon digging up a human skull. Although he didn’t assume the role of quantitative paleontologist in his published articles, he was always careful to pick up the skulls and limbs of every creature he found, and so he built up a great store of unexploited data other scientists could use for quantitative research. (Some excavators will “high-grade” a deposit, collecting only the rarer species, thus ruining the sample for reconstruction of the entire ecosystem.) In his office were the results of his life’s work forty years of expeditions to the richest finback-bearing strata of Texas and New Mexico. Romer was always gracious and generously shared even his unpublished information. He supplied me with precise details of what and how much he had found in the quarries.