When I got to Harvard, I had fun chatting with Romer about how my theories agreed with his. (dinosaur manufacturer)But then I got my comeuppance. As part of my Ph.D. work, I had to run lizards on miniature treadmills inside micro-environmental chambers to measure just how hard they had to breathe to run at different speeds. (Hot, boring work for me and the lizards—each run was thirty minutes and I needed twenty runs per lizard.) When the results came ticking out of the oxygen analyzer, I was devastated—and my theory was totally deflated. My sprawling lizards were more efficient than fully erect mammals and birds. (dinosaur factory)All the lizards used less energy to run at any given speed than did birds or mammals of the same size. As the old laboratory saying goes “The theorist proposes, Nature disposes.”
I trotted into Romer’s office the next day and sadly announced, “Our theory is dead.” Then I plopped the computer printout on his desk. Romer scrutinized it. (animatronic dinosaur costume)Then with a twinkle in his eye and a mock inquisitorial tone in his voice he said, “Your data are probably correct. But they must be suppressed. Our beautiful theory has got to be preserved.” I felt better. If Romer could chuckle, so could I.
So what advantage is the fully erect gait? Probably it allows for much higher speeds even if efficiency is sacrificed. Having a vertical limb stroke means that you can exert more of a thrust downward onto the ground with your paws. (realistic dinosaur models)And the speediest gaits require such thrust to propel the body when all feet are airborne.