Earth & Sky

“Luck and Persistence: A Scientific Career” by today’s featured scientist Thomas Rich.

Information Sheet on Victoria’s dinosaurs, from the Museum Victoria.

Dinosaur Dreaming: Research from the Monash University. Paleontology Laboratory

More about hypsilophodontids.

Or try this hypsilophodontid page.

Transcript of an interview with Dr. Rich:

Q: Please describe your research.

A: My principal place of research is southeast of Melbourne at a place called Flat Rocks, near the town of Inverloch. And what we’re doing is we’re working in an early Cretaceous site that’s yielding dinosaurs and mammals and occasional birds, fish, and turtles, and that sort of thing.

What makes the site interesting is the fact that these animals were living inside the Antarctic Circle, so you got a question as to how did they do it, how did they physiologically function at that high latitude? Because we’ve got evidence nearby as to the presence of permafrost. Now, nowhere else in the Mesozoic era at the time that dinosaurs lived is there evidence of permafrost that’s ever been reported in the literature. So it was probably pretty nippy down here, so dealing with that is what makes this assemblage rather interesting.

Q: Once you and your colleagues found out that indeed dinosaurs were living in these kinds of conditions, the natural question of how dinosaurs survived came up. How long ago did that question come up?

A: Just about the time we started discovering it, people starting realizing that the latitude in this part of Australia was very high. And you’ve got to understand, there’s about 15 or 20 polar dinosaur sites around the world. My wife and a colleague in Alaska two years ago published in Science, a summary, where we got a map in there, where we plot the localities. Ours is not the only one, it’s probably the most intensely studied, because of the simple fact that logistically the cheapest one you can work on, because most of these sites are remote high latitude positions today, and just getting to them is rather expensive.

Bill Hammer, who is at Augustana College in the US has been working in Antarctica, in the Transantarctic Mountains, he’s got some fossils from there. What he told me, if I’ve got the numbers right, was that it costs a quarter of a million dollars to keep one person in the field for a season, which is six weeks. We’ve run our digs for about 20 years, for less than a half a million dollars, and we have 15 people every summer on site. That gives you an idea of the difference in cost. That’s one of the reasons we’ve been able to go so far so fast, because it’s cheap.

Q: Obviously the continents have shifted ? How would you describe where they lived back then?

A: Actually, Australia and India are the two major landmasses that have changed latitudes significantly in the past 100 million years. Places like North America have moved west, but they haven’t really shifted a lot ? Alaska, for example may have shifted three to five degrees, where Australia, we’ve shifted about 40. That’s the difference. That’s why Alaska is still polar ? the area where the dinosaurs come from just hasn’t shifted that much south. It’s shifted a little bit but not a lot.

Q: What do you think the weather conditions were like?

A: Here, certainly when the permafrost existed the average temperatures were down around ?5 degrees C. , -10 or ?15 degrees F. We know that when the permafrost was there, it had to be that cold, but what we don’t know is there’s three meters of rock, about 10 feet between the permafrost and where we get the dinosaurs and the mammals that lived alongside them. That could represent about 20,000 years. 20,000 years ago northern Europe and northern North America were under a kilometer of ice. It would’ve looked like parts of Antarctica today. And that’s all gone in just 20,000 years. Now if that 3 meters of rock represents 20,000 years, there may have been fluctuations like that that back when the dinosaurs?

So it would’ve meant you would have had conditions going from like Fairbanks Alaska to Montana. Not exactly turning into a tropical paradise, but that kind of range. We just don’t know. We’re trying to work that out. We’ve got one way of trying to do it with fossil pollen, and that may indicate that the temperatures stayed as cold as when the permafrost was laid down.

Q: How do you look at fossil pollen and tell?

A: The thinking is that the diversity of species goes up when the temperature goes up. And what we’ve found is that the number of species at the level you’ve got the permafrost evidence and the number of species where we got the fossil bones is the same. So the thinking is that probably the temperature remained constant. Because you don’t get evidence of permafrost everywhere when it would’ve been cold enough. You have to have very special conditions. That doesn’t mean it wasn’t cold enough to form it, you just have to be in the right place.

Q: How do you think these dinosaurs were adapted to these conditions, and did they hibernate?

A: Did they hibernate? That implies that all of them did. We don’t think that all of them did. We have one group of dinosaurs called hypsilophodontids, which look like kangaroos. If you took a kangaroo and gave it shave and cut off its ears, it would look a lot like these dinosaurs. They were small herbivores running around on two legs. They didn’t hop; they ran.

What’s interesting about them, is that here in southeast Australia, we have about six different kinds, maybe more. Elsewhere in the world, when you get this group of dinosaurs, you get maybe one species or two. What we found out is that the brain has a structure on it called the optic lobe. And the optic lobe is basically what processed the visual signal that comes in through the eyes. You don’t see with your eyes, you see with the brain. What’s interesting about the dinosaurs is that this one brain we have, the optic lobe is very large, much larger than the low latitude ones that we can examine.

The other thing is that, a colleague by the name of Anusuya Chinsamy, who is located in Cape Town, South Africa, looks at the cross sections of bone and tries to interpret them. And what she did was she looked at the cross section and said these animals never slowed down metabolically, they had a uniform metabolic rate year round. Now if you’re going to hibernate you can’t do that. You’re going to form a different kind of bone. There’s a technical term called line arrested growth. What this means is that when metabolism slows down, bone is still laid down, but much slower and much denser, so when you do a cross section you get dark bands, sort of like tree rings. And these dinosaurs don’t have them.

Other dinosaurs from our site do. You can get these bands from hibernating, but you can also get them because there’s a shortage of water and a shortage of food. So the presence of a band doesn’t unequivocally establish that you’ve got something that’s hibernating, but the absence of it establishes that you sure don’t. It’s sort of a one-way test.

Q: You say that some dinosaurs may have hibernated and some didn’t – what about other strategies to deal with the seasonal temperatures, like migrating.

A: The problem with migrating?the dinosaurs are pretty small. If you can fly it makes energetic sense but if you can’t fly you got to walk, and you’re small, where you going to go? If you get to the Antarctic Circle it doesn’t mean you’re suddenly in the Bahamas. Just energetically it doesn’t seem favorable.

But there’s another problem in Australia. You’ve got to swim to get over the Antarctic Circle. Because the problem is to the north of us there’s an ocean. And it just doesn’t work. If you want to go to low latitudes in Australia and you’re a little hypsilophodontid, you’ve got to go diagonally across the continent. It would be kind of like going from Key West to Seattle.

That’s an awful lot of energy; it just doesn’t seem to make a lot of sense. Flying doesn’t cost as much per kilometer.

Q: What’s happened since the article I read was published, in the last 2 ? years or so, in terms of your research?

A: I’ve been interested in the mammals that we find alongside the dinosaurs. They’re interesting; they’re not what we expect. Australia is dominated by marsupials, apparently the placental animals, like us and whales and cows and lions, they give birth to very advanced young. Marsupials give birth to very immature young. And a lot of them have pouches and the young suckle.

Anyway, we’ve got some mammals that look like placentals. The thinking has been that marsupials did so well in Australia because there weren’t any placentals when they got here. And so what the heck is a placental doing in Australia in rocks twice as old as those with a marsupial?

We’re trying to work the answer out to that. It could be the placentals went extinct along with the dinosaurs, perhaps. And then the marsupials did get here and there were no placental mammals on the ground. There were probably bats, but no ground placental animals. But it’s just curious that we have a mammal that looks like a placental. This is very controversial. A lot of our colleagues don’t buy it, but that’s what makes science fun. Nobody ever predicted this.

Knowledge of dinosaurs, most of the groups we got, we got in the first ten years, and it’s sort of plateaued. I wrote an article for Scientific American with my wife in July 1993. Not much new since then. Fossils are not that abundant in Australia.

When my wife and I started this work in the late 70s, there was one bone of a dinosaur known from the state that we live in, Victoria, and that was it. So everything that we know about the dinosaurs here in southeast Australia, is everything we collected, except for that one bone.

When we first got here, we went in the field and hoped we’d find a good site. The results were meager. Our best results were here, but by other people’s standards, people would say why bother. We started with nothing. We’ve named five dinosaurs, and could probably name another five if we pushed it.

In a sense it’s like the US in 1880.

Q: Do you also work on exhibits at the museum?

A: It takes up one case! We have casts of dinosaurs from overseas. That’s the way it goes. I wouldn’t recommend anyone following in our footsteps, Very restricted. Only one square mile. In Queensland a lot of rocks very badly weathered. Never get a situation like in the US, where a lot of skeletons are near each other. Not a quarry situation.

Q: Are there any other issues we should talk about?

A: When you look at where Australia was when these animals were living and dying, the connection to the outside world really should go via Antarctica to South America, which means you’d expect the dinosaurs to look like South American dinosaurs. In fact, the gap to the north is much bigger than it is now. After all even as close as Australia is to Asia, the immigration of forms to the north isn’t really restricted, we’ve got rats coming in here in the last 5 million years, but really nothing else in terrestrial mammals that weren’t brought in by people.

When you look at the scraps of dinosaurs we have, really bits and pieces, as best we can determine, these dinosaurs don’t look like south American forms like you’d expect, they look like Asian forms. And I just wonder about, why is that? The only explanation I can come up with is, if you look at the geologic history of china on west to India and Iran and Europe. In the last 3 or 400 million years, from the southern continents, Gandwana, pieces of real estate have been breaking off and drifting off and smashing into Asia. So the only way I can see of getting these dinosaurs from Australia into Asia is if these dinosaurs took the raft and went north. The problem with that is that the trip took about 80 million years. And you’d think that the dinosaurs would change in 80 million years.

This is a way to explain the phenomenon, the fact that you get this affinity between the north and Australia rather than across Antarctica and South America, but it seems like you’re really pushing it to come up with this model and defend it. I’ve proposed it but I don’t take it all too seriously. So the question is, is it that we just don’t know enough about the dinosaurs, which is highly likely, or is it that there was a connection with Asia, which seems anomalous, but it was there.

Thanks to:

Thomas H. Rich
Curator of Vertebrate Paleontology
Museum Victoria
Melbourne 3001
Victoria, Australia