Robert T. Bakker

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When the dinosaurs fell at the end of the Cretaceous, they were not a senile, moribund group that had played out its evolutionary options. Rather they were vigorous, still diversifying into new or­ders and producing a variety of big­brained carnivores with the highest grade of intelligence yet present on land.

Robert T. Bakker (born March 24, 1945) is an American paleontologist who helped reshape modern theories about dinosaurs, particularly by adding support to the theory that some dinosaurs were endothermic (warm-blooded). Along with his mentor John Ostrom, Bakker was responsible for initiating the ongoing "dinosaur renaissance" in paleontological studies, beginning with Bakker's article "Dinosaur Renaissance" in the April 1975 issue of Scientific American. His special field is the ecological context and behavior of dinosaurs.

Quotes[edit]

The problem is this: if the later synapsids were such splendidly advanced animals with the improved physiology of mammals, and if dinosaurs were slow and sluggish, why were the mammal-like synapsids exterminated in competition with the first dinosaurs?
The dinosaurs are not extinct. The colorful and successful diversity of the living birds is a continuing expression of basic dinosaur biology.
If we measured success by longevity, then dinosaurs must rank as the number one success story in the history of land life.
No lizard ever evolved the birdlike characteristics peculiar to each and every dinosaur.
  • Most experts have assumed that the allosaurs, about 35 feet long, were the worst threats to the herbivores of the Jurassic, some of which were gigantic and probably able to fend off even an allosaur. But epanterias would have spelled trouble for everyone.
  • Even 'Jurassic Park III' tried to jump on the avian-dino bandwagon by making a brave attempt to adorn Velociraptor with a feathery hair-piece. (The result looked like a roadrunner's toupee- don't blame the effects-artists; it's notoriously difficult to render feathers in computer graphics animation, so we'll have to wait for 'JP IV' for a more thoroughly rendered avian pelage.)
    • “Dinosaurs Acting Like Birds, and Vice Versa – An Homage to the Reverend Edward Hitchcock, First Director of the Massachusetts Geological Survey” in Feathered Dragons. Currie, P.; Koppelhus, E.; Shugar, M.; Wright J. eds. 2004. Bloomington: Indiana University Press. pp. 1-11.
  • The rex bite is unique among better known dinosaurs. Instead of inflicting a long, shallow wound, rex jaws would thrust a few crowns deep into bone armor, killing a Triceratops with a single blow. We see close-linked co-evolution here, a terminal Cretaceous arms race. Triceratops is the commonest horned dino of the time, the final dinosaurian Age, the Lancian. T’tops departs from the ceratopsian tradition of frill construction. Torosaurus, very rare during the Lancian Age of the Cretaceous, retains that basic design: the frill is composed of thin bone rods that make a frame, with huge holes in the middle. Triceratops fills in the holes with greatly thickened bone. Why would Triceratops invest in five times as much bone volume in its frill? Well…to me the answer is obvious. Because the commonest predator has evolved great, armor-penetrating teeth. The argument goes in the other direction – T. rex evolved swollen, tall tooth crowns to deal with the unusual protection of the commonest horned herbivore.

The Superiority of Dinosaurs (1968)[edit]

  • The classical view of dinosaurs presents a perplexing problem. The group of vertebrates which dominated the land before the rise of the dinosaurs were the synapsids, the mammal-like reptiles... Most paleontologists have believed that the locomotion and physiology of these mammal-like synapsids were more similar to those of active, warm-blooded mammals than to sluggish modern lizards or alligators. Surprisingly, though, when the first dinosaurs and their near relatives appeared in the Triassic period, the synapsids began to decline and soon became extinct. The dinosaurs then ruled the land unchallenged for over 100 million years while the early mammals, the surviving descendants of the synapsids, remained very small in size and number. Only after the dinosaurs suddenly disappeared about 70 million years ago did the mammals develop into the great variety of dominant land vertebrates we have today. The problem is this: if the later synapsids were such splendidly advanced animals with the improved physiology of mammals, and if dinosaurs were slow and sluggish, why were the mammal-like synapsids exterminated in competition with the first dinosaurs? And why didn't the mammals achieve a more significant diversification during the dinosaurs' reign?
    • "The Superiority of Dinosaurs", Discovery 3(2),(1968) 11–22

Dinosaur Renaissance (1975)[edit]

  • The dinosaur is for most people the epitome of extinctness, the proto­type of an animal so maladapted to a changing environment that it dies out, leaving fossils but no descendants.
    • "Dinosaur Renaissance", Scientific American 232, no. 4 (April 1975), 58—78
  • Dinosaurs have a bad public image as symbols of obsolescence and hulking in­ inefficiency; in political cartoons they are know-nothing conservatives that plod through miasmic swamps to inevitable extinction.
    • "Dinosaur Renaissance", Scientific American 232, no. 4 (April 1975), 58—78
  • One might expect that mammals would have taken over the land verte­brate communities immediately, but they did not. From their appearance in the Triassic until the end of the Creta­ceous, a span of 140 million years, mam­mals remained smal and inconspicuous while all the ecological roles of large ter­restrial herbivores and carnivores were monopolized by dinosaurs; mammals did not begin to radiate and produce large species until after the dinosaurs had al­ready become extinct at the end of the Cretaceous. One is forced to conclude that dinosaurs were competitively su­perior to mammals as large land vertebrates. And that would be baffling if dinosaurs were "cold-blooded." Perhaps they were not.
    • "Dinosaur Renaissance", Scientific American 232, no. 4 (April 1975), 58—78
  • When the dinosaurs fell at the end of the Cretaceous, they were not a senile, moribund group that had played out its evolutionary options. Rather they were vigorous, still diversifying into new or­ders and producing a variety of big­brained carnivores with the highest grade of intelligence yet present on land.
    • "Dinosaur Renaissance", Scientific American 232, no. 4 (April 1975), 58—78
  • I do not be­lieve birds deserve to be put in a taxo­nomic class separate from dinosaurs.
    • "Dinosaur Renaissance", Scientific American 232, no. 4 (April 1975), 58—78
  • The dinosaurs are not extinct. The colorful and successful diversity of the living birds is a continuing expression of basic dinosaur biology.
    • "Dinosaur Renaissance", Scientific American 232, no. 4 (April 1975), 58—78

The Dinosaur Heresies (1986)[edit]

  • 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 animals, 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 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?
    • The Dinosaur Heresies: A Revolutionary View of Dinosaurs (1986), Longman Scientific & Technical, p. 16
  • 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... 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 dominant position in life on land. Instead, the mammal clan was but one of many separate evolutionary families that succeeded as species 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.
    • The Dinosaur Heresies: A Revolutionary View of Dinosaurs (1986), Longman Scientific & Technical, p. 17
  • 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 limbs must have operated like the limbs of gigantic birds.
    • The Dinosaur Heresies: A Revolutionary View of Dinosaurs (1986), Longman Scientific & Technical, p. 20
  • Dinosaurs are not lizards, and vice versa. Lizards are scaley reptiles of an ancient bloodline. The oldest lizards antedate the earliest dinosaurs by a full thirty million years. A few large lizards, such as the man-eating Komodo dragon, have been called "relicts of the dinosaur age", but this phrase is historically incorrect. No lizard ever evolved the birdlike characteristics peculiar to each and every dinosaur. A big lizard never resembled a small dinosaur except for a few inconsequential details of the teeth. Lizards never walk with the erect, long-striding gait that distinguishes the dinosaurlike ground birds today or the birdlike dinosaurs of the Mesozoic.
    • The Dinosaur Heresies: A Revolutionary View of Dinosaurs (1986), Longman Scientific & Technical, p. 22-23
  • No one, either in the nineteenth century or the twentieth, has ever built a persuasive case proving that dinosaurs as a whole were more like reptilian crocodiles than warm-blooded birds. No one has done this because it can't be done.
    • The Dinosaur Heresies: A Revolutionary View of Dinosaurs (1986), Longman Scientific & Technical, p. 27
  • The total turtle count - two hundred and thirty species - doesn't seem like an irresistible horde compared to the several thousand mammals in today's global ecosystem. However, turtles have scored quite an impressive ecological triumph in one very important role, that of freshwater predator-omnivore... All through the Temperate Zone, otters delight the naturalist and the lay public. But how many other freshwater, semi-aquatic mammal predators can you name? Mink, of course. Relatives of otters on one hand, land weasels on the other, mink do hunt in streams. How many others? If you caught the excellent BBC series "Life on Earth", you saw footage of the swimming shrew, the Desman of the Pyrenees, a molelike furball that dives for aquatic worms and other freshwater small fry. Our own New England star-nosed mole goes hunting in water, using its starburst-shaped snout tip to feel out wriggling prey. Andean streams flowing through Preu are host to the fish-spearing mouse, Ichthyomys, that impales prey on its projecting front teeth. But if we go to a tropical lake or sluggish river, is it full of otters, mink, and paddling shrews? No, it is full of turtles.
    • The Dinosaur Heresies: A Revolutionary View of Dinosaurs (1986), Longman Scientific & Technical, p. 57
  • Up to eight feet long and as heavy as a lioness, the adult Komodo dragon brandishes steak-knifelike teeth - sharp, recurved blades with serrated cutting edges. Showing the same sagacity found in veteran Nile crocodiles, fully adult dragons know their hunting territory from years of experience. They know where to lie along hilly game trails, awaiting the light footsteps of a deer. Attacks are instant successes or failures because the ora has no stamina, and if it misses on the first short rush, it has little sustained speed for a long pursuit. When an attack succeeds, the cruel rows of slashing teeth cut fearful wounds on the rump and thigh of ambushed animals and the stricken prey may die of massive infection days later even if it manages to break free from the dragon's mouth. Tethered livestock suffer truly terrible cuts across the legs when an ora slinks into the compound under cover of the warm Indonesian nights. Several humans, both native and European visitors, have died in savage daylight attacks. The victims simply had no warning sign that the ora was waiting patiently a few feet from the trail's edge.
    • The Dinosaur Heresies: A Revolutionary View of Dinosaurs (1986), Longman Scientific & Technical, p. 62-63
  • Our own mammalian order, the primates, prides itself on hand-eye coordination, monkeys, apes, and man are all good manipulators. But no mammal can rival the chameleon for eye-tongue coordination.
    • The Dinosaur Heresies: A Revolutionary View of Dinosaurs (1986), Longman Scientific & Technical, p. 68
  • Giant predator lizards can't evolve in the presence of big mammal predators. So the lesson is that mammals suppress much of the evolutionary potential of modern lizards. Is the Komodo dragon a good working model of how dinosaurs succeeded? Absolutely not. Dinosaurs suppressed the evolutionary potential of mammals, not the other way around. And dinosaurs carried out this supression everywhere, on all the continents, not merely on a few tiny tropical isles. Dinosaurs succeeded where Komodo dragons fail.
    • The Dinosaur Heresies: A Revolutionary View of Dinosaurs (1986), Longman Scientific & Technical, p. 81
  • The message from the tropics is unambiguous: To be a successful big land animal, you must cope with mammals, and to cope with mammals you must be a mammal yourself, or at least have metabolism as high as a mammal's. And big mammals have suppressed big reptiles in our tropics for the last sixty-five million years. So how can the dinosaurs' success over mammals' be explained? By assuming that dinosaurs had low-energy metabolic styles? Not very likely.
    • The Dinosaur Heresies: A Revolutionary View of Dinosaurs (1986), Longman Scientific & Technical, p. 101
  • Zoos mislead their visitors by the way the species are housed. Birds are in the Bird House, of course, and crocodiles are always segregated to the Reptile House with the other naked-skinned, scale-covered brutes. So the average visitor leaves the zoo firmly persuaded that crocodilians are reptiles while birds are an entirely different group defined by "unreptilian" characteristics - feathers and flight. But a turkey's body and a croc's body laid out on a lab bench would present startling evidence of how wrong the zoos are once the two stomachs were cut into. The anatomy of their gizzards is strong evidence that crocodilians and birds are closely related and should be housed together in zoological classification, if not in zoo buildings.
    • The Dinosaur Heresies: A Revolutionary View of Dinosaurs (1986), Longman Scientific & Technical, p. 127
  • Both birds and crocs have the identical plan to their specialized gizzard apparatus, and this type of internal food processor is absent in the other "reptiles" - lizards, snakes, and turtles.
    • The Dinosaur Heresies: A Revolutionary View of Dinosaurs (1986), Longman Scientific & Technical, p. 127
  • By themselves, brontosaur gizzards don't indicate how much or what these dinosaurs ate each day; other lines of evidence must be employed to explore these questions. But brontosaur gizzards and teeth together indicate what brontosaurs did not eat. They didn't eat soft, mushy vegetation. Birds that subsist entirely on soft fruits don't possess muscular gizzards and don't use hard pebbles for their gizzard linings. Soft, watery food requires only a short, simply constructed gut - with just enough contractile force to squeeze out all the juices.
    Brontosaur teeth, moreover, confirm the heretical idea that they ate a tough vegetable diet. If the brontosaurs dined only on soft water plants, then very little wear would be found on their teeth. But in fact the teeth of Camarasaurus, Brachiosaurus, and their kin manifest very severe wear, which could only have been produced by tough or gritty food.
    • The Dinosaur Heresies: A Revolutionary View of Dinosaurs (1986), Longman Scientific & Technical, p. 136-137
  • Duckbills were supposedly croc-style swimmers, moving by strong, easy, side-to-side flexures of their tail. Therefore, the optimal design would feature vertical tail spines. But duckbill spines all slanted strongly backward, exactly as in land-living lizards, not in swimmers.
    Another problem in the duckbill's swimming equipment lies in the profile of the tail. The deepest part of the croc's tail is close to the end, because the end swings through a wider arc than does the base in moving side to side. Thus the tail is deepest where it can do the most good in pushing against the water. All powerful tail-scullers have such deep tail ends. But duckbill tails were deepest at the hips and become progressively narrower from top-to-bottom toward the tip - another caudal feature nearly totally maladapted for its primary function.
    • The Dinosaur Heresies: A Revolutionary View of Dinosaurs (1986), Longman Scientific & Technical, p. 153
  • The sum of evolutionary evidence is thoroughly damning. In nearly every modification of the evolutionary process made in the duckbills as they developed from their dryosaur ancestors, the duckbills suffered a diminution of their swimming potential. Their fore- and hind paws became shorter and more compact, not longer and more widely spread. Their tails got weaker and stiffer. Far from being the best, the duckbills must have been the clumsiest and slowest swimmers in all the Dinosauria. If pressed, they probably could paddle slowly from one riverbanck to another. The central theme of their bodily evolution was indeed specialized - orthodox theory was right on that point - but the direction of specialization was landward. These dinosaurs were specialized for a totally terrestrial existence.
    • The Dinosaur Heresies: A Revolutionary View of Dinosaurs (1986), Longman Scientific & Technical, p. 154-155
  • There may be some ground for believing that brontosaurs ate... soft foods. If the possibility of gizzard stones is ignored, the brontosaurs' dentition does seem little equipped to deal with meals of tougher plants. But there are no ground whatsoever for believing it of duckbills. The mouth of a duckbill dinosaur contained one of the efficient cranial Cusinarts in land-vertebrate history. Duckbill teeth and jaws were incomparable grinders, designed to cope with foods right inside the duckbill's oral compartment.
    • The Dinosaur Heresies: A Revolutionary View of Dinosaurs (1986), Longman Scientific & Technical, p. 160-161
  • No living reptile has cheeks. But no living reptile has grinding teeth anything remotely resembling those of a duckbill. If the duckbills could have evolved such unreptilian teeth, why couldn't they have evolved unreptilian teeth?
    • The Dinosaur Heresies: A Revolutionary View of Dinosaurs (1986), Longman Scientific & Technical, p. 165
  • Plants and plant-eaters co-evolved. And plants aren't the passive partners in the chain of terrestrial life. Hence today's Pop Ecology movement is quite wrong in believing that plants are happy to fill their role as fodder for herbivores in a harmonious and perfectly balanced ecosystem. A birch tree doesn't feel cosmic fulfillment when a moose munches its leaves; the tree species, in fact, evolves to fight the moose, to keep the animal's munching lips away from vulnerable young leaves and twigs. In the final analysis, the merciless hand of natural selection will favor the birch genes that make the tree less and less palatable to the moose in generation after generation. No plant species could survive for long by offering itself as unprotected fodder.
    • The Dinosaur Heresies: A Revolutionary View of Dinosaurs (1986), Longman Scientific & Technical, p. 179
  • Without doubt the most dangerous devices for active defense among the Dinosauria emerged in Triceratops. The scene has been portrayed in paintings, drawings, and illustrations hundreds of times, but it remains thrilling. Tyrannosaurus, the greatest dinosaur toreador, confronts Triceratops, the greatest set of dinosaur horns. No matchup between predator and prey has ever been more dramatic. It's somehow fitting that those two massive antagonists lived out their co-evolutionary belligerence through the very last days of the very last epoch in the Age of Dinosaurs. Tyrannosaurus stood over twenty feet tall when fully erect, and a large adult was as heavy as a small elephant - five tons. No predatory dinosaur, no predatory land animal of any sort, had more powerful jaws. Withstanding a Tyrannosaurus's attack required either tanklike armor – the approach taken by Ankylosaurus – or most powerful defensive weapons - the approach taken by Triceratops.
    • The Dinosaur Heresies: A Revolutionary View of Dinosaurs (1986), Longman Scientific & Technical, p. 240-241

See also[edit]

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