The Joker Who Says that Dinosaurs May Have Been Warmblooded. by Steve Brusatte
by Steve Brusatte
Every profession has a foremost character. Clarence Darrow provided laughs for lawyers. Charles Barkley has always been an oddball basketball star. And then there is Bob Bakker. Robert T. Bakker is far and wide paleontology\'s greatest and most well known character.
You probably know Bakker as the man who hypothesized that dinosaurs may have been warmblooded, or the scientist who believed that diseases caused the demise of the terrible lizards, or the author who wrote the book the Dinosaur Heresies. But, there is much more to the career of Dr. Robert Bakker.
As a child Bakker caught the dinosaur bug at an early age. While in the 4th grade he read the classic December 7, 1953 Life Magazine with awe. This magazine, which Bakker describes as the most famous single magazine article focusing on dinosaurs, quickly changed his life. He took his love of dinosaurs to Yale University, where he studied under the great John Ostrom. Bakker later received his Ph.D. from Harvard University.
As an undergraduate Bakker held many small part time jobs as a scientific illustrator. While at Yale he taught children visitors of the college museum as part of the school services program. As a Ph.D. student he was in charge of the Harvard comparative anatomy labs. He then received his first major job from the Johns Hopkins University in Baltimore, Maryland.
He taught anatomy to premed students before he left in 1982. After he departed he has taught at the University of Colorado and has held numerous jobs at several museums in Colorado and Wyoming, including the Tate Museum, where he is now the Adjunct Curator. Bakker has become so involved with these museums that one of his current goals is to develop a web of the smaller Wyoming museums, which number 8, and create a single, major museum chain. Bakker is noted most for his theoretical work, but he has also partaken in a great deal of field work. Since the summer of 1974 he has returned to Como Bluff summer after summer in order to attempt to put dinosaurs in context.
Bakker points out that whenever you look at a painting that portraits mid Jurassic life you see all groups of dinosaurs living together. From Diplodocus to Apatosaurus to Stegosaurus to Camarasaurus, they are all present in one environment. For twenty five years now Bakker has been slaving away in the hot, barren outcrops of the American west not to collect great specimens, but to sample every possible habitation.
Bakker\'s Colorado field work has produced numerous results. Among his findings, he has located dinosaurs that lived in totally aquatic environments, and others that could have only lived in trees. He can also tell you that Stegosaurus was only common on well drained, dry soil. Apatosaurus and Camarasaurus were found everywhere, Bakker stated.
He is also focusing on the mysterious Jurassic-Cretaceous boundary. Bakker points out that at the boundary between these two periods you see a large extinction, with most of the animals that had been common dying out and the smaller, less common ones diversifying. To test this hypothesis Bakker traveled to South Africa to study the late Permian and Triassic extinctions, and discovered that they followed the same pattern. He also points out that this very same scenario took place at the K-T extinction, with the small mammals seizing the evolutionary crown from the dinosaurs.
One of Bakker\'s most notable discoveries was of Epanterias. In 1990 Bakker and his team discovered some neck and tail bones, jawbones, and teeth north of Denver, Colorado. He quickly noticed that the dinosaur who once owned these bones and teeth was an amazing creature. He describes it as the last member of the Allosaur group in North America with a skull similar to Allosaurus, legs thicker than Allosaurus, and longer, but lower than T. rex, with smaller teeth.
This rare animal was only found in the last time slice of the Jurassic, he points out. Bakker also believes that this beast proves one of Edward Cope\'s greatest theories. In the 1800\'s Cope stated that animals get bigger and bigger and then get too large, and die out. As Bakker says, this is not only the last member of the Allosaur family, but also the largest.
Bakker has also done a great deal of field work in other states, including Montana, Utah, Oklahoma, other countries, including Mongolia, Zimbabwe, and Canada, and in numerous other quarries. He has also discovered the only complete Apatosaurus skull and the very first and earliest raptor found in the Camarasaurus quarry.
While Bakker\'s field record is very impressive, he is internationally known for his controversial theories that continue to light up paleontology, and science in general. The hypothesis that is always mentioned in the same breath as Bakker is his theory of warm blooded dinosaurs. He points out that in 1836 Edward Hitchcock, while studying dinosaur footprints, misidentified them as those of hawks. As Bakker says, this simple misidentification showed that the walking habits of dinosaurs exhibited a type of high metabolism, like that of birds.
In 1841, Bakker again points out, Richard Owen said that the dinosaurs were almost hot blooded and that they approached the habits of mammals. Using these two historical conclusions, Bakker published his first paper on dinosaur endothermy in 1968. This paper focused on the history of mammals and reptiles. If you follow the history of mammals and dinosaurs, Bakker says, you can see that the Permian and Triassic mammal like reptiles were very similar to actual mammals in the fact that, as he says, they were warm blooded.
When the first true mammals appeared they were small. This is very strange to Bakker that a group of creatures so advanced would go from large to tiny if the dinosaurs were less advanced, cold blooded creatures. In a nutshell Bakker says that the dinosaurs only could have replaced these advanced mammal like reptiles if they were warm blooded.
While the notion of warm blooded dinosaurs is one that is almost impossible to prove, Bakker looks to dinosaur bone and dinosaur lungs. According to Bakker, dinosaurs had hollow back bones that included air chambers leading to the lungs, like birds. He also draws conclusions from his colleague, Armand de Ricqles, who\'s career has focused on the growth rates of dinosaur bones. Many suggest that by studying the growth rates and blood canals in bone, you can simply tell if a dinosaur was warm blooded, but as de Ricqules and John Horner have pointed out, it is not that
simple. For this reason, it will be extremely difficult to prove Bakker\'s theory in the future.
In the late 70\'s and early 80\'s Horner and Bob Makela excavated numerous Maiasaura eggs and nests in Montana. These finds became the first concrete proof that some dinosaurs did care for their young. Since Horner and Makela\'s discoveries some have pointed out that meat eaters may not have cared for their young, but Bakker tends to think differently. With help from another monumental field discovery Bakker has drawn up another interesting hypothesis.
In Wyoming Bakker discovered the first proof of nesting habits in Allosaurs. According to him, there were several spots where Allosaurs dragged prey to feed their young. He also says that there are numerous spots where you can find broken teeth of babies and adults, which were probably caused by eating on something large. One example is his discovery of baby Allosaur teeth in an Apatosaurus bone. Another example is his discovery of every size tooth from a habitat, from hatchling to adult, in one spot. These discoveries had led to his theory that young Allosaurus hatchlings were fed at the nest until they were full grown, the same behavior seen in eagles and hawks.
While these two theories are controversial, the hypothesis that Bakker has drawn the most heat for has been his notion that the dinosaurs were killed off not by an asteroid or volcano, but by disease. According to Bakker, a comet or asteroid would have killed everything. Instead, the answer lies in migration. When big animals are spreading and mixing, he says, extinctions occur. He points to the findings that Indian and African elephants make each other sick to strengthen his belief. \"When a new animal or plant is introduced to a new habitat bad things happen,\" he stated.
Bakker also uses the record of land bridges forming and animals spreading to further prove his theory. \"Some snails don\'t spread fast, so they don\'t become extinct,\" he said. \"Land bridges were everywhere during extinction, many species were spreading, and there were many diseases. The biggest danger to native wildlife is foreign wildlife.\" Despite his fame, Bakker is still currently in the midst of many projects. First and foremost is his work on sound reconstruction in Apatosaurus. He believes that the head of Apatosaurus vibrated to make sound. Several of the bones that are tightly bound in other dinosaur species are loosely hinged in Apatosaurus, he says. \"When Apatosaurus sneezed its whole eye socket would rattle,\" he stated. He thinks this may be true in many herbivorous dinosaurs.
He also teaches a field school in the summer. He has been doing this for ten years. For more information on this school call 1-800-DIG-DINO. Of course, he will also return to Como Bluff for further Jurassic studies.
The paleontology career of Dr. Robert T. Bakker has been full of exciting finds and controversial theories. While he may draw fire for some of his ideas, it is safe to say that Bakker\'s theories have led to the new image of dinosaurs-smart, active, caring, and highly interesting beast
Dr. J. John Sepkoski
This portrait is dedicated to Dr. J. John Sepkoski. Jack was truly one of the paleontological greats, with his theory of mass extinctions occurring every 26 million years. Sadly, he recently died of heart failure at the age of 50. He will be deeply missed.