A Fitting Final Portrait of the past Millennium by Steve Brusatte
A portrait of Nicholas Hotton III
by Steve Brusatte
As the dawn of the new millennium each and every one of us finds ourselves remembering the greatest events of the last thousand years. The same holds true with paleontology, a science that was invented during the last millennium. Over the 300 year history of the field several men have risen from the ranks of researcher to fossil icon; the names Cuvier, Mantell, Buckland, and Brown come to mind. The theories and discoveries of these men will remain for centuries, and they will be admired for countless millenniums to come.
This past December paleontology tragically lost one of these icons, Dr.Nicholas Hotton III. While he will almost certainly be remembered for his theories regarding dinosaur metabolism, his pioneering studies of prehistoric reptiles have broken many barriers in our never-ending quest to learn more about the past.
Young Nick Hotton was first introduced to the field of paleontology at the 1934 World\'s Fair in Chicago, where he got the chance to view a series of new mechanized dinosaurs. But, the love that he first met at the fair that day in Chicago laid dormant until he left his Michigan home to attend junior college in the small midwestern town of LaSalle, Illinois. Oddly enough, on a personal note, LaSalle is only a 15 minute drive by car from my home town of Ottawa, Illinois, and I discovered this fact during my phone interview with Dr. Hotton. Suddenly, I felt a bond with him.
Others have told me the same thing. After his junior college days at LaSalle County Community College Hotton left for the University of Chicago, where he received a Bachelor\'s Degree in geology and a Ph.D. in paleozoology. From Chicago he took his first paleontology related job at the University of Kansas, where he taught human gross anatomy in their medical school for eight years, from 1951- 1959. In 1959 Hotton made, arguably, the biggest move of his career, when he took a job at the Smithsonian Institution as the Curator of Vertebrate Paleontology for the National Museum of Natural History. He remained at the Smithsonian until his death.
Hotton considered his specialty to be fossil amphibians and reptiles, and throughout his many years in paleontology he added much to our current thinking about early tetropod evolution. For instance, early in his career he renamed the South African reptile species Kombuisia. During the process of its discovery, many of his fellow scientists believed that Kombuisia was actually an amphibian, but in his words, Hotton, \"shot them down.\" He took another look at the fossil and declared it to indeed be a reptile. Hotton spent many of his summers involved in numerous paleontological expeditions around the world, including a haven for reptile and mammal fossil lovers, South Africa, and the fossil rich state of Texas. In fact, one of the greatest moments of his paleontological career occurred in Texas. He described one hot summer, a year with an unusually high number of coyote sightings, in which he found an amazingly preserved skull. \"It was only me there, and all of a sudden you see this twinkle in the ground and it is a skull.
That is a great moment, a rush, to realize it is so old, and it has never been seen by humans before.\" Hotton also recollected on another great paleo moment he witnessed in Texas. He described it as being another very hot summer, one in which a paleontological idol of his was partaking in his final expedition of his long career. \"Arnie Lewis decided to take one more trip to the field and he found an amazing fossil. He came up the hill triumphantly, it usually took a lot to get Arnie excited, carrying a skull,\" Dr. Hotton told me. \"Texas was a very unique place,\" he went onto say, a place that he loved dearly.
Even though he named and studied many amphibians and reptiles throughout his years, Dr. Hotton will probably be best remembered for his work on dinosaur endothermy. In the late 1960\'s a young Yale University paleontology student named Robert Bakker created quite a stir when he suggested that some dinosaurs may have indeed been warm blooded, quite a difference from the cold-blooded lizards that they were portrayed as. This initial announcement caused decades of debates on the subject, until the entire subject was deemed closed by a large conference of paleontologists in the early 1980\'s. Nicholas Hotton played a crucial role in this conference, and his findings are considered bench marks in the continuing debates of dinosaur endothermy and dinosaur migration today.
During the long debates on endothermy paleontologists from around the globe debated with each other in ways that were never seen before by the paleontological world. Each announcement was met with a counter-announcement. Each counterannouncement was denied by the other side. In fact, two large cliques were formed during the debates, the side favoring warm blooded dinosaurs, and the side leaning towards the notion that all dinosaurs were cold blooded. But, Dr. Hotton\'s announcement was one of the first that didn\'t lean towards either side. Instead, it took into account the facts presented by each group and explained dinosaur endothermy in a way that was never suggested before.
In the book he helped compile, \"A Cold Look at the Warm Blooded Dinosaurs,\" Hotton suggested this notion: what if dinosaur migration helped the creatures keep a constant and reasonable body temperature? In his article \"An Alternative to Dinosaur Endothermy: The Happy Wanderers,\" Hotton argued that, \"all large dinosaurs, herbivores and predatores alike, would have had to be wanderers in order to gather enough food to keep themselves going.\" This fact has been proven by fossil finds in remote, cold areas such as Alaska and Antarctica. Plus, some vast dinosaur trackways, such as those studied by Martin Lockley, have suggested migrating dinosaurs.
Don Lessem, in his 1992 book \"Dinosaurs Rediscovered\" went onto write, \"By moving, slowly and steadily, dinosaurs could have warmed themselves without being warm blooded. By moving north or south in keeping with moderating temperatures, they would remain away from climatic extremes that would chill or overheat them. Dinosaur migration could thus be compared to the sun-following movements of lizards, scaled up to giant size.\"
So, basically in a summed-up manner, Hotton suggested that large dinosaurs, because of their giant size, could have kept a constant body temperature. Plus, some dinosaurs could have kept a safe and constant body temperature by migrating and avoiding conditions that could be too hot or too cold. Much like the story book character Golidlocks, the dinosaurs migrated to keep a body temperature that was \"just right.\"
Hotton\'s contributions have also been felt in the debates of dinosaur-bird evolution and plate tectonics. He has consulted deeply with controversial paleontologist Sankar Chatterjee of Texas Tech University to create a new theory on plate tectonics. Conventional wisdom tells us that the subcontinent of India was an island throughout most of the dinosaur times before later slamming into Asia, creating the Himalayas.
But, after analyzing dinosaur remains, Hotton and Chatterjee created their own theory, which is still heavily debated to this day. After their analysis of Indian, African, and Asian dinosaur fossils, Hotton and Chatterjee noticed that the fossils on all three continents were greatly similar, leading them to hypothesize that India must have been linked to Africa and Asia for most of the dinosaurian times.
But, as mentioned above, geologists have used evidence from sea-floor spreading to temporarily disprove this theory. After his hiatus from studying reptiles and amphibians to concentrate on dinosaurs, Hotton returned to his first love during the 80\'s. In fact, at the time of our interview (about 9 months before his death), three papers he had written were currently in press. One of them had to do with the CAT scanning of the skull of Ophiacodon, a Texas reptile related to the famous Dimetrodon. The next paper focused on a set of trackways in New Mexico, and the third was a paper on a frog.
In fact, the paper on the frog may have been Hotton\'s most interesting paper of the trio. Until his studies, paleontologists believed that frogs originated in the Jurassic period. But, Hotton told me, \"we have a specimen in Texas from the early Permian. It looks like a salamander, but has a frog skull.\" This paper, posthumously, may once again prove conventional wisdom wrong.
Sadly, this was as far as Dr. Hotton got in his long career. During early December 1999 he died peacefully at his home. For years nothing could stop him from digging deep into the past, but he finally succumbed to colon cancer at the age of 84. On that cold December day a truly great career came to an end. A fitting tribute to a great scientist, a fitting final recollection, a fitting first portrait of the new millennium.