When nineteenth-century scientists examined slices from fossil bones and teeth, they found that dinosaur bone looked very like mammal bone. (dinosaur manufacturers)Both dinosaurs and mammals possess many tiny channels for blood vessels running through their bone, and both have the curious structures known as Haversian canals long cylinders, pointed at both ends, where bone mineral had been dissolved and then redeposited in concentric layers. When cut in cross section, Haversian systems look like tiny onions sliced across the middle.(dinosaur factory) Cut lengthwise, they resemble tiny, multi-layered electrical cables.
Using this technique, early twentieth-century scientists assembled an impressive body of histological data about the entire 400-million-year history of vertebrates from the earliest fish to Neanderthal Man. (animatronic dinosaur)And all the dinosaur bone slices looked more like mammal bone than reptile. These studies were masterfully summarized in a series of papers published in the early 1950s by two histologists from Texas, Enlow and Brown. But their labors had astoundingly little impact. The standard textbooks on dinosaurs had hardened into “cold-blooded” orthodoxy. And so the work done by these histologists remained in relative obscurity.
The material concerning the texture of the dinosaurs’ bones and their rates of growth burst upon the world in the 1970s thanks to two independent rediscoveries of the old published work. By purest chance I ran across some articles dealing with the texture of dinosaur bones and subsequently was led to the wealth of information published by Enlow and Brown. They had cut samples from dozens of dinosaurs and concluded that the animals may have been warm-blooded. In 1972, I published a paper in the journal Nature, calling attention to all this forgotten material. (dinosaur costume)Meanwhile, in Paris, Armand de Ricqles had also rediscovered the question of bone texture and had inaugurated a massive research project involving hundreds of new thin sections. I’ve cut a few fossil thin sections myself, but de Ricqles is the unchallenged bone-slicing champion of all time. He has cut and polished samples from nearly every type of prehistoric vertebrate. And the evidence he provides for warm-blooded growth patterns in dinosaurs is over-whelming and incontrovertible.