Robert T Bakker Read online

  Copyright © 1986 by Robert T Bakker

  Illustrations copyright © 1986 by Robert T, Bakker

  All rights reserved. No part ot this book may be reproduced or

  utilized in any form or by any means, electronic or mechanical, including

  photocopying, recording or by any information storage and retrieval

  system, without permission in writing from the Publisher Inquiries

  should be addressed to Permissions Department, William Morrow and

  Company, Inc., 105 Madison Ave.. New York NY 10016.

  Library of Congress Cataloging-in-Publication Data

  Bakker. Robert T

  The dinosaur heresies

  Includes index

  1. Dinosaurs. I. Title.

  QE862.D5B35 1986 5679'1 86-12643

  ISBN 0-688-04287-2

  Printed in the United States of America

  4 5 6 7 8 9 10

  BOOK DESIGN BY ANN GOLD

  To a dear friend, Professor Bernhard Kummel of Harvard Uni-

  versity. Bernie grabbed me by the lapels back in 1974 and said,

  "Kid, you can't go on being an enfant terrible forever. You gotta

  write a book." So Bernie, here's your book.

  PREFACE

  It all started very suddenly, in the spring of 1955. I was reading

  magazines in my grandfather's house in New Jersey, and I found

  that magical Life cover story—"Dinosaurs." Fold-out, full-color

  pictures of heroic creatures. Allosaurus, Brontosaurus, Stegosaurus,

  Tyrannosaurus rex. I discovered an entire world, far, far away in

  time, that I could visit, whenever I wanted, via the creative labors

  of the paleontologists. And I made up my mind then and there

  that I would devote my life to the dinosaurs. Since I was in the

  fourth grade, my parents weren't alarmed at my vow. Surely, they

  thought, it's just a phase that he'll grow out of. Lots of kids my

  age got hooked on dinosaurs for a while—it was a childhood dis-

  ease, like mumps or chicken pox, and if left alone, most kids re-

  covered and then had a lifetime immunity to dinosaurmania. But

  I was that rare exception, a terminal, chronic case. And my mother

  was patient enough to take me twice a year over the George

  Washington Bridge to the American Museum of Natural History

  in New York, where the best dinosaur show in the world played

  every day of the week on the fourth floor. My family valued

  scholarship, even if they couldn't quite understand the reverence

  I had for the study of fossils.

  I owe a great deal to a few fine friends at Harvard. Bernie

  Kummel always encouraged me, even though we seemed to rep-

  resent opposite extremes of college society—he a member of the

  Old Guard, I one of the sixties radicals. But we both loved fossils.

  Bryan Patterson taught me about rodents and giant ground sloths

  PREFACE I 9

  and elephants, and, most especially, how wonderfully complex the

  fossil history of life was. Steve Gould was always stimulating, and

  challenging, and fiercely protective when occasion demanded. I

  would not have survived Harvard without these three.

  I must tip my well-worn cowboy hat to Ms. Kate Francis, of

  the Johns Hopkins University. Kate was a loyal friend, invaluable

  critic of my prose, and superb manuscript manipulator all through

  the first three drafts of this book. Maxine Mote was a soul mate

  at Hopkins, too, and helped with some key chapters. Many a time

  I sat for hours in the hallway at Hopkins discussing dinosaurs and

  evolution with my old friend from Yale, Steve Stanley, now a pro-

  fessor of paleontology at Hopkins. Steve is a clam-paleontologist

  at heart, but his mind roves far afield, wherever the fossil record

  of life leads to neat discoveries about how evolution works. Thank

  God for the WATS line—we can still have these long rambling

  talks long distance.

  And a fond thank-you to all the Hopkins pre-meds who helped

  to dig at Como—-Jan Koppelman, Robert Beck, Conrad Foley, Sue

  Reiss, and especially Julius Goepp. They're all doctors now, or

  almost.

  To my editor, Maria Guarnaschelli, I owe an enormous debt

  for her patience, encouragement, and extraordinary creative en-

  ergy. She is passionate about making good books, and she suc-

  ceeds.

  Constance Areson Clark loves dogs, old books, and the Bad-

  lands as much as I do, and most of my ideas about how evolution

  works have been explored during our walks in the rain in Balti-

  more or lingering breakfasts in Greybull, Wyoming. Constance,

  Wyoming, and I were destined to come together, and stay to-

  gether.

  And, finally, I must acknowledge my debt to hundreds of

  people I have never met. The fieldmen who dug dinosaurs in the

  1880's. The skilled preparators who chiseled bones out of the rock

  in countless basement laboratories. The exhibit craftsmen who bent

  the ironwork to mount the skeletons. All the people who have kept

  the great museums going for the last century. I love museums more

  than any other institution the human race has invented. Museum

  people are always overworked and underpaid, and they all deserve

  sainthood, every one.

  10 | PREFACE

  Preface 9

  PART I

  THE CONQUERING COLD-BLOODS:

  A CONUNDRUM

  1 Brontosaurus in the Great Hall

  at Yale 15

  2 Wyoming Reverie: Meditation on

  the Geological Text 29

  3 Mesozoic Class Warfare:

  Cold-Bloods versus the Fabulous Furballs 48

  4 Dinosaurs Score

  Where Komodo Dragons Fail 75

  PART II

  THE HABITAT OF THE DINOSAURS

  5 The Case of the Brontosaurus:

  Finding the Body 105

  6 Gizzard Stones and Brontosaur Menus 125

  7 The Case of the Duckbill's Hand 146

  8 Dinosaurs at Table 160

  9 When Dinosaurs Invented Flowers 179

  PART III

  DEFENSE, LOCOMOTION, AND THE CASE

  FOR WARM-BLOODED DINOSAURS

  10 The Teutonic Diplodocus:

  A Lesson in Gait and Carriage 201

  11 Mesozoic Arms Race 226

  12 Defense Without Armor 255

  13 Dinosaurs Take to the Air 273

  14 Archaeopteryx Paternity Suit:

  The Dinosaur-Bird Connection 298

  PART IV

  THE WARM-BLOODED METRONOME

  OF EVOLUTION

  15 Sex and Intimidation:

  the Body Language of Dinosaurs 325

  16 The Warm-Blooded Tempo of

  the Dinosaurs' Growth 347

  17 Strong Hearts, Stout Lungs,

  and Big Brains 361

  18 Eaters and Eaten as the Test of

  Warm-Bloodedness 375

  •

  PART V

  DYNASTIC FRAILTY AND THE PULSES

  OF ANIMAL HISTORY

  19 Punctuated Equilibrium:

  the Evolutionary Timekeeper 395

  20 The Kazanian Revolution:

  Setting the Stage for the Dinosauria 406

  21 The Twili
ght of the Dinosaurs 425

  22 Dinosaurs Have Class 445

  Notes and References 463

  Index 473

  A Note About the Author 482

  PART 1

  THE CONQUERING

  COLD-BLOODS:

  A CONUNDRUM

  Two bull Brontosaurus

  1

  BRONTOSAURUS IN THE

  GREAT HALL AT YALE

  I remember the first time the thought struck me! "There's some-

  thing very wrong with our dinosaurs." I was standing in the great

  Hall of Yale's Peabody Museum, at the foot of the Brontosaurus

  skeleton. It was 3:00 A.M., the hall was dark, no one else was in

  the building. "There's something very wrong with our dinosaurs."

  The entire Great Hall seemed to say that. I had grown up with

  the dinosaurian orthodoxy about dinosaur ways—how they were

  swamp-bound monsters of sluggish disposition, plodding with

  somnolent strides through the sodden terrain of the Mesozoic Era.

  Dimwitted and unresponsive to change, the dinosaurs had ruled

  by bulk. Bizarre and exotic shapes ornamented their heads and

  bodies like the decadent opulence of a Byzantine palace. Books

  and museum labels solemnly preached the same message—the di-

  nosaurs were failures in the evolutionary test of time. Stories of

  their mode of life were replete with negatives: Brontosaurus couldn't

  walk on land because its body was too heavy. Diplodocus couldn't

  feed on anything but soft water plants because its head was too

  small. Duckbill dinosaurs couldn't run quickly because their limb

  joints were too imperfect. Pteranodon couldn't flap its wings be-

  cause they were too weak. Dinosaurs couldn't be warm-blooded

  because their brains were too small. And the final, ultimate failure

  of their character—dinosaurs couldn't cope with competition from

  the smaller, smarter, livelier mammals.

  BRONTOSAURUS IN THE GREAT HALL AT YALE | 15

  All of these "couldn'ts" together built up the orthodox view

  ofdinosaurs as a dynasty of flawed creatures. And it was this or-

  thodoxy that suddenly seemed so wrong as I stood looking at the

  Brontosaurus in the Great Hall. The public image of dinosaurs is

  tainted by extinction. It's hard to accept dinosaurs as a success when

  they are all dead. But the fact of ultimate extinction should not

  make us overlook the absolutely unsurpassed role dinosaurs played

  in the history of life.

  Creatures with four legs first crawled slowly out of the an-

  cient swamps 400 million years ago. Dinosaurs were not in this

  first evolutionary wave, nor in the second or third. Contrary to

  the cartoonists' view of geological history, dinosaurs aren't the most

  ancient of life forms, not even close. Dinosaurs as a clearly de-

  fined group don't make their grand entrance until 200 million years

  after the first four-legged beasts emerged from the primordial

  swamps. By the time they appear in the land ecosystem, the

  woodlands and waterways were already full of creatures, large and

  small, flesh-eater and vegetarian. For a brief twilight zone—five

  million years, short by geological standards—these earliest dino-

  saurs shared the terrestrial realm with a host of older clans. But

  then the dinosaurs seized power. They took over all the large roles

  in the land ecosystem. They filled the offices of mega-predator and

  mega-herbivore. Their control of the land ecosystem was com-

  plete. No nondinosaur larger than a modern turkey walked the land

  during the Age of Dinosaurs.

  If we measured success by longevity, then dinosaurs must rank

  as the number one success story in the history of land life. Not

  only did dinosaurs exercise an airtight monopoly as large land an-

  imals, they kept their commanding position for an extraordinary

  span of time—130 million years. Our own human species is no

  more than a hundred thousand years old. And our own zoological

  class, the Mammalia, the clan of warm-blooded furry creatures, has

  ruled the land ecosystem for only seventy million years. True, the

  dinosaurs are extinct, but we ought to be careful in judging them

  inferior to our own kind. Who can say that the human system will

  last another thousand years, let alone a hundred million? Who can

  predict that our Class Mammalia will rule for another hundred

  thousand millennia?

  If we measure success of a zoological dynasty by the defense

  16 I THE CONQUERING COLD-BLOODS: A CONUNDRUM

  of its borders, then the Dinosauria must rank as the most robust

  of ruling clans. Dinosaurs were not unopposed in the world-game

  of competition and predation. As the early Dinosauria spread their

  species into every role open to large land creatures, the dinosaurs

  were driving out the last remnants of very advanced and very

  specialized clans, zoological tribes which had been evolving and

  perfecting their adaptive equipment for tens of millions of years.

  Like the Mongol hordes sweeping across the old cities of eastern

  Europe, dinosaurs wasted little time in expelling these well-

  established kingdoms. And during their long reign, the dinosaurs

  faced potential threats from dozens of new clans that evolved even

  higher grades of teeth and claws, bodies and brains. Despite the

  evolutionary vigor of the potential opposition, dinosaurs kept their

  ecological frontiers intact; no other clan succeeded in evolving to

  a large size as long as the Dinosauria existed.

  Humans are proud of themselves. The guiding principle of the

  modern age is "Man is the measure of all things." And our bodies

  have excited physiologists and philosophers to a profound awe of

  the basic mammalian design. But the history of the dinosaurs should

  teach us some humility. The basic equipment of our mammal class—

  warm bodies clothed in fur, milk-producing breasts to nourish our

  young—is quite ancient. These mammalian hallmarks are as old as

  the dinosaurs themselves. Indeed, the Class Mammalia emerged,

  fully defined, in the world ecosystems just as the Dinosauria be-

  gan their spectacular expansion. If our fundamental mammalian

  mode of adaptation was superior to the dinosaurs', then history

  should record the meteoric rise of the mammals and the eclipse of

  the dinosaurs. Our own Class Mammalia did not seize the domi-

  nant position in life on land. Instead, the mammal clan was but

  one of many separate evolutionary families that succeeded as spe-

  cies only by taking refuge in small body size during the Age of

  Dinosaurs. As long as there were dinosaurs, a full 130 million years,

  remember, the warm-blooded league of furry mammals produced

  no species bigger than a cat. When the first dinosaur quarry was

  opened in 1822 at Stonesfield, England, quarry men found the one-

  ton Megalosaurus and a tiny mammal.

  So the popular image of dinosaurs as unprogressive behe-

  moths is wrong. Political cartoonists use Brontosaurus as the ulti-

  mate symbol of ignorant lethargy and obsolete organization. In fact,

  18 I THE CONQUERING COLD-BLOODS: A CONUNDRUM

  The nineteenth century discovers the age of Dinosa
urian Giants. Scholars

  probing the fossil relics dug up in gravel quarries and clay pits early in the

  1800s were astounded by the unprecedented size of dinosaurs. By 1889,

  samples from all the major dinosaur clans had been found.

  dinosaurs evolved quickly, changed repeatedly, and turned out wave

  after wave of new species with new adaptations all through their

  long reign. Sir Richard Owen, best and brightest of Victorian anat-

  omists, coined the name "Dinosauria," from Greek roots meaning

  "terrible lizard," in 1842. When Owen first penned the word "di-

  nosaurs," paleontology was still a brand-new science. Baron Cu-

  vier had invented the scholarly art of reconstructing form and

  function in fossil creatures only forty years earlier. Though careful

  study of the earth's crusts had gone on for only one human gen-

  eration, the naturalists of 1840 already knew that an Age of Rep-

  tiles had preceded our own Age of Mammals. And the many

  skeletons already dug up showed that this Age of Reptiles was a

  time when fishlike reptilian forms swam in the seas and batlike

  reptilian species flew through the air. Owen invented the term

  "Dinosauria" to describe the huge land animals of this age. And

  his original definition is still good.

  When the first dinosaur skeletons were hewn out of gravel

  quarries in England during the 1820s and '30s, the gentleman-

  naturalist immediately recognized their strange combination of

  characteristics. These great fossils combined traits found in liz-

  ards, in birds, in mammals, and in crocodiles as well. Owen was

  especially impressed by the advanced, birdlike shape of dinosaurs'

  hip bones, and he used their characteristics to set dinosaurs apart

  from all other animals with backbones. And so can we. A very good

  anatomical definition for the Dinosauria is "a vertebrate group close

  to crocodiles but with at least some important birdlike features in

  the hind leg."

  Sir Richard Owen's astute observations are too often ignored.

  Twentieth-century paleontologists have fallen into the bad habit

  of reconstructing the dinosaurs' life functions by using crocodiles

  as a living model. But the earliest researchers of the nineteenth

  century proved beyond a doubt that the dinosaurs' powerful hind

  legs must have operated like the limbs of gigantic birds. And fur-