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
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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
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
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-