Fifteen Eighty Four

Question: What is the best place to search for fossils in Canada?

Perhaps the most famous fossil locality in eastern Canada is Joggins, Nova Scotia, home to marvelous small Carbonifereous-aged tetrapod vertebrates (lizard-like, but definitely not lizards!).

David: Presumably you are talking about dinosaur fossils, but remember that there are lots of localities where invertebrate fossils as well as plant fossils can be found. Many of these are national treasures (world treasures, really), and amateurs are not really permitted to collect these sites (professionals need very, very good scientific reasons to collect these localities, and permits to go with). Among the most famous in that category is the Middle Cambrian (~505 million years old) Burgess Shale, a ancient reef front that preserves an amazing collection of extraordinary arthopods (see SJ Gould’s book Wonderful Life for an appreciation of these). Perhaps the most famous fossil locality in eastern Canada is Joggins, Nova Scotia, home to marvelous small Carbonifereous-aged tetrapod vertebrates (lizard-like, but definitely not lizards!). For dinosaurs, the place to visit (although collecting is not possible at this point) is Dinosaur Provincial Park in Drumheller, near Calgary, Alberta. This is a Late Cretaceous suite of badlands covering some of the most prime dinosaur-bearing localities the world has ever seen. Rightly, it is now a World Heritage Site. Along with the incredible outcrops is the amazing Royal Tyrrell Museum, located in Drumheller, containing a world class collection of Late Cretaceous dinosaur fossils, mainly from Dinosaur Provincial Park. “World class” doesn’t actually do the place justice, since among the very best dinosaur museums on Earth. Not to be missed by any dinophile!

Question: Would you recommend us to do what Jurassic Park did?

You can’t recreate non-bird dinosaurs à la Jurassic Park because DNA has a shelf life (before it begins to degrade) of about a million years.

David: Your question is quite the ethical conundrum. You can’t recreate non-bird dinosaurs à la Jurassic Park because DNA has a shelf life (before it begins to degrade) of about a million years. But, there is considerable interest in restoring the parts of dinosaurs that have disappeared using genes that are currently not producing proteins but are still there, dormant, in the organism – just not activated. In birds (which are living theropod dinosaurs), people have attempted to restore tails and teeth; the results have been tantalizing, but not precisely satisfactory. Yet. But what you would end up with after such an effort is from this vantage point in our biotechnology, very unclear. Then you’re getting into the realm of Frankenstein which, as Mary Shelley pointed out long ago, is dangerous ethical territory, indeed.

Question: Did dinosaurs really have feathers?
David: Dinosaurs really had feathers. But remember, since all living birds are simply a type of dinosaur, it is not surprising that non-bird dinosaurs would have had feathers as well. Some of those feather types might have been a bit more primitive than we see in birds today, but many were not, and they were all certainly varieties of feathers.
As for “raptors” (not a word I love to use, since it already referred to a group of modern birds (like hawks, eagles, etc.) before people started using it to describe a particular type of dinosaur, the non-bird, extinct “raptors” were certainly coated in feathers, and of a type very familiar to us today. The evidence for this is absolutely clear – we see the the beautiful feathery impressions preserved surrounding the fossil bones of these animals.

We’ve all been socialized to think of dinosaurs as big, slow, stupid, naked beasts, but the fossil evidence directly contradicts all of this.

Finally, we’ve all been socialized to think of dinosaurs as big, slow, stupid, naked beasts, but the fossil evidence directly contradicts all of this. Here is how I like to think of it: birds are dinosaurs in exactly the same way that humans are mammals: Birds bear the features that make a dinosaur a dinosaur, just like humans bear the features that make a mammal a mammal. If we hadn’t been taught for so long – incorrectly, as it turns out – that dinosaurs looked and acted a certain way, we would all be more comfortable with birds as a type of living dinosaur. And then, the fact that they bore feathers would not be so incredible to contemplate.

Question: What made you interested in studying paleontology and how do you think the discipline has changed since you started teaching?
David: In the late 1950s, I read a book called All About Dinosaurs, by a man named Roy Chapman Andrews. It was incredibly inspiring to me (and others, as well: Roy Chapman Andrews was the model for Indiana Jones) but I never thought I could actually become a paleontologist – I didn’t know any; had never collected a fossil; and my in high school and college there was no opportunity to study such things. I didn’t even love the outdoors or camping that much. But the idea stuck in my head, and when RT Bakker published “Dinosaur Renaissance” in Scientific American in 1975, I decided that I just had to do it. Two years later it was time for graduate school, and I found that there was one Department of Paleontology in the entire United Sates (UC Berkeley) so I went. My far more paleontologically experienced and savvy friend Jim Clark – now a highly respected and accomplished paleontologist and professor at George Washington University – dragged me out to the field for the first time, and after a night of eating red beans & rice and hot Italian sausage, and sleeping in a ditch alongside of a field, I found my first fossil: the back part of the upper jaw of a Miocene dog-like creature called a borhyaenid. And that was all that was needed; I never looked back.

Of course the field has dramatically changed since those days; Jim and I (and our cohort) entered a world that was generally dominated by paleontologists who received their training in the 1950s and 1960s, and the dinosaurs that we know now are radically different from what we thought we knew about them then (see my answer to your other question below). Different, and much, much more interesting! in fact, when we showed up, dinosaur paleontology was kind of a backwater in the field; the heavy hitters of the day were the paleontologists who studied mammals. That inequality has surely changed (although some of our friends who study mammals might protest)!

Question: The areas that you find traces of dinosaurs, are they mostly in mountainous regions? Or valleys?
David: We find traces of non-bird dinosaurs wherever the rocks are sedimentary, terrestrial (e.g., not marine), and of the right age (~230 – 66 million years ago). These rocks can be preserved in valleys, in mountains, in deserts…wherever. The key is that generally, when there is a lot of human activity, it destroys the rocks (and fossils). So the places tend to be remote. When there is a lot of plant life, the acids in the plants tend to physically and chemically break down the rocks, and so fewer plants mean more pristine rock deposits. So the places tend to be not forested or verdant. When there is a lot of water and warmer temperatures, this tends to weather and break down the rocks as well. So the places tend to be drier and cooler, rather than wetter and warmer. But of course, there are many great fossil localities that have some of these criteria: great fossils come out of the Gobi Desert (of China and Mongolia) – no plants, dry, but hot (cold during the winters), and remote. Great fossils come out of various places in the American west – remote, generally, pretty dry, and hot during the summers (cold during the winters). But these are just generalities. The criteria I just listed simply improve the probabilities of finding fossils, and when they are found the preservation tends to be better. Determined, skillful paleontologists have found dinosaurs all over the world preserved in a very wide variety of different modern environments.

Question: What were the sea levels like when they lived?
David: Sea levels have varied through time, with some of the highest sea levels recorded having occurred ~113 million years ago. We think that there was no polar ice at that time, and thus all that frozen water was turned to liquid, raising sea levels. So changing sea level is completely normal on Earth; what is not normal is the rate of sea-level change (and ice melting) that we are experiencing today. Of course back in the days of the non-bird dinosaurs, if coastlines moved inland because of rising sea level, it was not so difficult for dinosaur populations to accommodate. Humans, however, are tied to our fixed coastlines, rigid land use, and built-up cities, all immobile structures that cannot sustain significant sea-level fluctuations. Moreover, the sea-level changes during the Mesozoic (and other times) occurred on geological (million-year) timescales; today, dramatic sea-level rise is occurring on 100-year timescales. This naturally has significant and far-reaching consequences for the Earth’s biota (us!), whether we want to acknowledge it or not.

Question: Have you found fossils that indicate they suffered diseases?

Even the famous T. rex “Sue” shows evidence of some profound periosteal membrane modification, attributed to chronic infection.

David: There is lots of evidence of dinosaur disease. One that we highlight in Dinosaurs is a bacterial parasite that likely caused visible lesions on the bones of dinosaurs. Elizabeth Rega in The Complete Dinosaur (2nd ed) provides a whole catalog of dinosaur “paleopathologies”, including arthritis, inflamed bone tissue, bone infections, and other pathologies. Even the famous T. rex “Sue” shows evidence of some profound periosteal membrane modification, attributed to chronic infection. Many dinosaur bones also show evidence of damage (such as might have occurred during an attack), and then in-life healing (if the animal lived to tell the tale).

Question: Which dinosaurs do you think were at the top of the food chain?
David: Classically, one would say that the top of the food chain was occupied by theropod dinosaurs such as Tyrannosaurus, or perhaps maniraptoran theropods like Deinonychus or the dromaeosaurs. They were the strictly carnivorous animals that depended upon herbivores for sustenance. I’ve always felt, however, that this was a vertebrate-chauvinistic viewpoint. I might call the top of the food chain the microorganisms that parasitize vertebrates, including big thundering carnivores like T. rex. Let’s face it, we all love big drooling carnivores – which also make for great movies – but without doubt the show is being run by microorganisms, particularly bacteria. They’ve got less star quality, but they’re in charge of this ecosystem as well as all the ecosystems that preceded it through 3.5+ billion years of life history! We exist in large part as a result of their largesse.

Question: Movies typically depicted Dinosaurs in lush vegetated areas. Were there dinosaurs that live on the equivalent of Antarctica or extreme desert environments?
David: Absolutely. My favorite dinosaur for unexpected climates is the little Mongolian ceratopsian Protoceratops and its diminutive desert antagonist Velociraptor. These dinosaurs, and the other members of their ecosystems lived (and died) in a sand-dune-rich Sahara like environment (properly termed an “erg” – a sand sea). Not only are their bones found in these environments, but their eggs and nests are found there as well. This was where they lived (as well as died).
As we note in Dinosaurs, dinosaurs are found as low a 88 degrees south latitude, and 80+ degrees north latitude. A rich dinosaur fauna is known, for example from Alaska’s North Slope. Dinosaurs must have been able to handle cold.

Question: What would your advice be to someone who wants to study dinosaurs in the future?
David: Get involved as much as you can now. Volunteer at museums; on digs If you’re college aged, try to learn as much as possible about the geosciences and the biosciences; a double major in these would be good.

Get involved as much as you can now. Volunteer at museums; on digs If you’re college aged, try to learn as much as possible about the geosciences and the biosciences; a double major in these would be good.

Remember that cool groups of animals – like dinosaurs – might be charismatic and attractive, but are not science. Ultimately, paleontology is a science, and thus ask interesting scientific questions; it should be the science that you are interested in, not just a few unusual vertebrates. Be very good at what you do.

To read the full session, click here.