Worlds in Chaos by James P. Hogan

thick and thin filaments and the number of cross-bridges between them,” he replied. “It turns out they’re about the same for a mouse as for an elephant—and it holds true across all the vertebrates. That means the only gain you get from larger size is what comes from the bigger cross section.”
    “There’s no increase in efficiency,” Keene checked.
    Robin shook his head. “In fact, it goes the other way. Gets worse.”
    “Okay. . . .” Keene searched for another way to play devil’s advocate. “They were aquatic. I saw a picture in a book once that showed them snorkeling around in lakes and swamps.”
    “Nobody believes that anymore,” Robin countered. “They don’t show any aquatic adaptations. Their teeth were worn down from eating hard land vegetation, not soggy watery stuff. They left tracks and footprints. That doesn’t happen under water.”
    “Did he find all this out by himself?” Keene asked, turning back to Vicki.
    “I helped him with some of it,” she told him—which Keene had guessed. “But it does seem to be a real mystery—a big one. You just don’t hear about it.” She made a vague gesture. “On top of the things Robin’s mentioned, you’ve also got the problem with the circulatory system of the sauropods—those were the ones that were all neck and tail. How did they get the blood up to their brains? A giraffe’s head might be twenty feet up, and it needs pressure that would rupture the vascular system of any other animal. Giraffes do it by having thick arterial walls and a tight skin that works like a pressure suit. But a sauropod’s brain was at fifty or sixty feet. The pressure would have needed to be three or four times that of a giraffe. The people who’ve studied it just can’t see it as credible.”
    “Hmm. Maybe they didn’t hold their necks upright, then,” Keene tried. “What if they walked around with them horizontal? . . . No.” He shook his head, not even believing it himself. What would have been the point of having them? And in any case, even without knowing the exact numbers, his instinct told him that the stress generated at the base would be more than any biological tissue could take.
    Robin concluded, “And then you’ve got things like the pterosaurs that somehow flew with body weights of three hundred fifty pounds, and predatory birds of up to two hundred. The most you get today is about twenty-five, with the Siberian Berkut hunting eagle. Breeders have been trying to improve on that for centuries, but that’s as far as you can go and still get a viable flier.”
    Keene looked at Vicki. “Any bigger, and you end up with a klutz,” she said. “The big gliding birds like albatrosses aren’t good flyers. They often need repeat attempts to take off, and they can be real clowns on landing.”
    Robin nodded. “That’s why they’re called gooney birds.”
    Vicki sat back and finished her coffee while Keene thought about what she and Robin had said. There didn’t seem any further line to pursue. “And the people in the business know these things?” he said finally. Of course they did. It was more for something to say.
    “Well, we sure didn’t make them up,” Vicki replied. “I guess they put it out of their minds and get on with cleaning up the bones and fitting them together or whatever. So what’s new?”
    It was Athena all over again—the reason Keene had quit physics to return to engineering. Most workers just got on with the day-to-day job that brought in the grants and kept the paychecks coming, without worrying too much about what it all meant. It was safer to write papers and textbooks about things that everyone agreed they knew than go dragging up awkward questions whose answers might contradict what people in other departments were saying they knew. Before long the whole edifice would be threatened, and the result would be trouble from all directions.
    “There must have been something vastly different about the whole reality