The Lost World of Jack Horner
An Interview With the World’s Most Famous Dinosaur Digger

By Michael Shermer

It is a well-understood fact that in order to do something significant in science you have to get your “union card,” the Ph.D. Yet, before this century most science was done by amateurs, gentlemen naturalists, natural philosophers, theologians interested in the correlation between God’s word (the Bible) and God’s works (nature), and the like. So John R. (Jack) Horner is something of a throwback to the tradition of science as done by credentials-be-damned rugged individualists, out in the field for the love of knowledge and little else.

At 50-something, this eldest native son from Shelby, Montana has all the trappings of a successful academic scientist: Curator of Paleontology at the Museum of the Rockies in Bozeman, Montana; recipient of a MacArthur Foundation “genius” fellowship; holder of an honorary doctorate of science from the University of Montana; and author of Digging Dinosaurs, Maia: A Dinosaur Grows Up, The Complete T. Rex, Digging Up Tyrannosaurus Rex, and his latest, Dinosaur Lives: Unearthing an Evolutionary Saga. But Horner is a self-made scientist, having failed to complete pre-requisites for a college degree and only risen as high as a “preparator” at Princeton University, which he described in Digging Dinosaurs as follows: “Preparators aren’t professors or curators, and under normal circumstances they have next to no chance of becoming professors or curators. Usually you find them in the dusty, windowless basements that more often than not pass for laboratories in paleontology.”

Where you would have found Jack Horner in the late 1970s, however, was in the dust of Montana, not Princeton, where, with little encouragement and no funding, he hit paleontological pay dirt—the now-famous dinosaur eggs from the Willow Creek anticline. He not only dug dinosaurs, however, he inferred behavior—dinosaur eggs clustered in constructed nests implies that at least some dinosaurs took care of their young, not exactly the image Hollywood has given us of these “terrible lizards.”

I first met Jack Horner in 1991 through my close friends Donna and Michael Coles, supporters of Horner’s research who also get out in the field and help dig up bones. That summer they were in the process of excavating a 140-million year old Apatosaurus (formerly known as Brontosaurus), and I got a chance to uncover one of its ribs (recounted in my essay in Vol. 4, #4 of Skeptic). What I witnessed was historical science at its best, with Horner hypothesizing each step of the way, always looking for ways to falsify his own assumption. In science this process is formally known as the hypothetico-deductive method, where one forms a hypothesis based on existing data, deduces a prediction from the hypothesis, then tests the prediction against further data. For example, in 1981 Horner discovered a site in Montana that contained approximately 30 million fossil fragments of approximately 10,000 Maiasaurs (described in Digging Dinosaurs). Horner and his team extrapolated this estimate from selected exposed areas in a bed 1.25 miles by .25 miles. The hypothesizing began with a question: “What could such a deposit represent?” (p. 129). There was no evidence that predators had chewed the bones, yet many were broken in half, length wise. Further, the bones were all arranged from east to west—the long dimension of the bone deposit. Small bones had been separated from bigger bones, and there were no bones of baby Maiasaurs, just those of individuals between nine and 23 feet long. What would cause the bones to splinter lengthwise? Why would the small bones be separated from the big bones? Was this one giant heard, all killed at the same time, or was it a dying ground over many years?

An early hypothesis of a mud flow burying the herd alive was rejected because “it didn’t make sense that even the most powerful flow of mud could break bones lengthwise…nor did it make sense that a heard of living animals buried in mud would end up with all their skeletons disarticulated.” Horner constructed another hypothesis: “It seemed that there had to be a twofold event, the dinosaurs dying in one incident and the bones being swept away in another.” Since there was a layer of volcanic ash 1.5 feet above the bone bed, volcanic activity was implicated in the death of the herd. From this hypothesis he deduced that only fossil bones split lengthwise, therefore the damage to the bones came long after the dying event, which might have been a volcanic eruption, especially since volcanoes “were a dime a dozen in the Rockies back in the late Cretaceous.” This hypothesis-deduction process led to this conclusion: “A herd of Maiasaura were killed by the gases, smoke and ash of a volcanic eruption. And if a huge eruption killed them all at once, then it might have also killed everything else around,” including scavengers or predators. Then perhaps there was a flood, maybe from a breached lake, carrying the rotting bodies down stream, separating the big from the small bones (which are lighter) and giving them a uniform orientation. “Finally the ash, being light, would have risen to the top in this slurry, as it settled, just as the bones sank to the bottom” (pp. 129-133).

Such paleontological digs are good examples of hypothetico-deductive reasoning and how historical science can become experimental when one makes predictions based on initial evidence that are then verified or rejected by later evidence. The digging up of history, whether bones or letters, is the experimental procedure of the historical scientist putting his hypothesis to the test, and Horner has proven that you don’t need a Ph.D. to do it, and do it well. In May, 1997, I sat down with Jack in his laboratory, to find out what hypotheses and theories he was testing, and in the process what dinosaur stereotypes and cherished beliefs he was shattering.

Skeptic: I’d like to cover the gamut of personal, theoretical and experimental stuff. Let’s begin by discussing the sequel to Jurassic Park, The Lost World. The dinosaurs seem to be a little too PC—dinosaurs with family values. To what extent is this influenced by our culture of “family values” and we want our animals to reflect what we would like to be true?

Horner: Most of the dinosaur behavior stuff is based on my work—the ideas of dinosaur nesting, herding, all that stuff, is based on research. What’s happened is that Spielberg and company have taken it as far as they want to take it. The nurturing idea I think can be demonstrated pretty conclusively; dinosaurs cared for (that is, protected) their young. Crocodiles do and birds do, and dinosaurs are in between. The same reasoning applies with dinosaurs being colorful or dinosaurs making noise. Crocodiles do, birds do, therefore dinosaurs probably did as well.

Skeptic: What was your biggest beef with The Lost World?

Horner: I liked it, but my biggest beef with movies in general is when animals get revenge. In The Lost World everything is getting revenge, the T. rexes in particular. Humans take the baby, fix it up, then give it back to the parents, who then come back and kick the crap out of all the vehicles, including heaving a Mercedes M-Class and Winnebago off the cliff. They’re getting even. Animals simply don’t do that. But film producers do this to make it exciting. If they didn’t, it would be a documentary.

Skeptic: So it’s really a projection of ourselves onto these animals.

Horner: Absolutely. That’s the anthropomorphic side of it that very few people recognize. Because we do it, we don’t really recognize that other animals don’t do it.

Skeptic: Speaking of revenge, there’s a character in the movie with a hat and long hair and beard that seems to resemble another famous paleontologist, but he bites the dust.

Horner: He disagrees with a lot of things I say.

Skeptic: Speaking of revenge!

Horner: That’s just reward!

Skeptic: What is the fascination of dinosaurs to all of us—and especially to children? Is it the gigantic size?

Horner: I think it has to do with the fact that they’re big, they’re different from anything alive today and they’re gone. So we get to use our imaginations. They really are the “living monsters.”

Skeptic: The science of Jurassic Park. Could it ever happen?

Horner: It probably can never happen because DNA probably doesn’t last that long. We have extracted DNA here at my lab but we can’t prove that it belongs to the dinosaur; there just isn’t enough to prove that. And even if there were, there isn’t enough DNA to do anything with it.

Skeptic: You’d have to fill it in with so much other stuff, it wouldn’t be a dinosaur.

Horner: Yes. If you added frog DNA to it you’d have a frog with an attitude. You don’t gain anything. We may actually learn something from some of the protein extractions we’re doing.

Skeptic: Would you comment on the texture, color, skin, and sound of dinosaurs? In a larger context, it used to be that you couldn’t infer behavior from fossils, but you pioneered this whole inference.

Horner: Never say no. The idea of determining the color of a dinosaur was considered absolutely impossible, and yet there is evidence that there may be some color patterns left in the fossil record—carbon films that actually reflect the color patterns—and if we can extract proteins from these patterns we will know what color some dinosaurs were!

Skeptic: Do you think you could tell if they had stripes or spots?

Horner: We may be able to even determine what color the stripes were and what color the spots were.

Skeptic: How would you extract the proteins?

Horner: We extracted proteins from our T. Rex. We got collagen; we’ve even extracted heme (from hemoglobin). So it may be quite possible to do this. I think it’s something that could be a lot more productive in determining stuff about dinosaurs than DNA ever would be. But getting back to your question: if we could clone a dinosaur, should we? No. It wouldn’t do any good. Even if we could clone a dinosaur, it wouldn’t do us a bit of good because all of us multi-cellular organisms depend on other organisms to keep us going. We have gut bacteria that help us feed. What did the dinosaurs have? There are so many other organisms that we depend on for our life support systems, and we’re too far away from dinosaurs. There is no environment to keep a dinosaur going. We don’t know what they ate; you might bring back a dinosaur that feeds specifically on a particular kind of plant and you wouldn’t know which one it was. Even if you could bring all the plants back, your dinosaur would be dead before he figured out what he really did eat. As far as the meat-eaters go, maybe they would be fine. Maybe you could get one to actually survive, but its unlikely.

Skeptic: What are some of the other new statistical methods you are using, such as computer models?

Horner: We CAT scan a lot of material and we have some software, and some hardware that allows us to reconstruct those CAT scans. A three-dimensional CAT scan image has tremendous amounts of data. You look at a dinosaur skull and it is a three-dimensional piece but you can’t see inside it. But with a CAT scan you can look at its brain size. I’m interested in dinosaur sounds, so I’m mapping the areas of the nasal passages through the skull, then I’m going to re-create this passageway.

Skeptic: In your research you also seem to use a comparative method of inference from modern species’ behavior, in addition to empirical data from the ground.

Horner: Right. And on a cladogram with modern taxa with dinosaurs, you have crocodiles, which would be the outgroup to dinosaurs and birds; and dinosaurs and birds would be a clade. The conservative view would be that they would be like alligators, that they would have the same characteristics, the same physiology, the same everything as crocodiles. But this is not supported by the paleontological data on dinosaurs. The fact that we find baby dinosaurs in nests that are bigger than what would have hatched out of the eggs that we find, suggests that they stay in the nest longer. With crocodiles, as soon as the babies are born they scoop up the babies in their mouths and haul them down and put them in a little “water nursery” area, which is very similar to “cresching” [CHECK SPELLING] in birds where the babies are hatched out of the eggs and they can walk but they don’t go very far. They’re just kept together in a creche that a few adults watch over as other animals are going out to get food.But rather than saying dinosaurs are bird-like and altrucial and stay in the nest, people who want to say that dinosaurs are like crocodiles argue that maybe they left the nest, took a walk, then came back to it. But there’s no precedence for it, no examples, and besides that it doesn’t make any sense.

Skeptic: Why is this coming out now? Why didn’t people infer behavior from fossils 80 or 100 years ago?

Horner: Because dinosaurs were always thought to be reptiles. As long as they were considered reptiles they were burdened by the same baggage that all reptiles have. We think of reptiles as being stupid, sluggish, and walking around looking for a place to go extinct. And this is what people thought of dinosaurs. You talk to people about dinosaurs 25 years ago and basically what you heard was “they couldn’t stand the change in climate,” “they weren’t smart enough,” “they were just waitin’ to go extinct!” Right—they were around 150 million years, but they were waiting! What comes from this is the a priori idea that dinosaurs have to fit the mold of reptile. The problem is the Linnaean classification system. We create a group; we look at the characters this group has, then when we find something else that fits in that group, it has to have the same characteristics. And the crazy things that came out of it were things like dinosaurs dragging their tails. When the early skeletons were found, the duckbilled dinosaurs had bony tendons in the tail that would keep their tails up, but people knew that these things were reptiles so they took the tendons off and broke the tail, sometimes in three places to get it to sit on the floor so that dinosaurs would be dragging their tails like all reptiles do! Think about the preconceived ideas that would cause you to do that. It’s incredible.

Skeptic: This is a classic example of theory driving observation.

Horner: Yes, but it wasn’t even theory. It was “fact” to people in those days. Dinosaurs were reptiles; therefore they were stupid and dragged their tails, assuming they did all the things that lizards do today.

Skeptic: In your new book, Dinosaur Lives, and in this course you taught at the university on “Science and Religion,” you talk about this Linnaean typological thinking as the single biggest problem in getting people to understand evolution as as a constantly changing system. Not only among the populace at large, but among scientists.

Horner: I think the Linnaean system is the worst thing we’ve hung onto from pre-Darwin; I think it has created most of the biological misunderstandings that we have, certainly in the general public. The general public’s understanding of biology is based on the Linnaean system that everything fits in a box. That’s why we can’t explain evolution, why we can’t define it, because we can never find the transitional taxon. We talk about things like archeopteryx, this transitional taxon between reptiles and birds, but at the class level, and things don’t evolve at the class level. They don’t even evolve at the species level. They evolve at the individual level, whether you call it a population or whatever you want to call it, it is still at the individual level. And so here we are talking about a transitional organism between classes. That’s bullshit. There’s no such thing.

Skeptic: What about this latest find of a transition fossil between dinosaurs and birds in Argentina? Is that the same thing.

Horner: Yes. They’re talking about the union of dinosaurs and birds. Well, some dinosaurs and birds—and all birds—have a common ancestor. But you’re not looking at an ancestor or a descendant; you’re looking at sister groups. And they have a common ancestor, but they didn’t find the common ancestor.

Skeptic: So you would replace the Linnaean system with a continuum of change?

Horner: My personal feeling of what we should do is that I don’t mind using the same naming system—we have to name things so we can talk about them. I’m still of the opinion that we can name things at the genus level; it doesn’t matter what that level is; we can never define it anyway. It’s a very subjective thing. But if we have a new kind of organism, then we give it a genus name. We name new genera, we name new species all the time. We can continue doing that. But we shouldn’t have a binomial because a binomial is about the most useless thing on the planet! If you think about Homo sapiens, what is the definition of sapiens? It is the same as Homo. It remains that way until you find a different species. Once you have two species, then you can define the two species separate of Homo. When you find a new species and it is a new genus, you have to describe the species and genus as the same thing. They both are given the same definition, because you can’t separate them. Skeptic: So Homo erectus, Homo neanderthalensis and Homo sapiens are anatomically modern humans. How would you group these?

Horner: Well, that’s one of the problems that everyone has, in defining these things. We’re looking at a modern human; we can’t even compare a modern human to a fossil human because most of our defining characters are soft tissue. Some have suggested hyphenating the genus and the species. Part of the problem is that there are lots of examples of transitions in the fossil record, but every time we find a new species we give it a new name. And if we give a whole bunch of things new names obviously there’s nothing to suggest that something is a “transition,” so one of the things I propose to do is actually use version numbers; in other words “Homo 1.0.,” “Homo 1.5”.

Skeptic: You want to simply put them in chronological sequence.

Horner: Right. We don’t know that we really have one, but we can hypothesize that we have one. If we start with Tyrannosaurus 1.0 then we find another one that looks different in a transitional sense—and it has to be a transformation and not just different characters—then we would know it is a transitional.

Skeptic: This would be a fuzzy classification system, rather than traditional logic, with binary systems or groups without fuzzy transitional forms between them.

Horner: Right. If you had a cladogram, and you have A, B, C and D (see Figure 1 below) and they’re related this way even if they are ancestors and descendants, this is how they’re related to one another. If I were proposing that this is the direction of evolution, then I could say that this has a taxonomic name and we’ll call it Tyrannosaurus. And we’ll call this one Tyrannosaurus 1.0, and here’s 1.5 and here’s 1.6, and here’s 2.0. It doesn’t matter how you do it; but this is showing a closer relationship.

Skeptic: So in finding a so-called transitional form between B and C , all you’re going to have is 1.5.5.

Horner: That’s right. Absolutely.

Skeptic: This would end a lot of time spent on debating this whole classification thing.

Horner: It surely would. And we do have examples of these things. But we also are encouraged not to look for them. And this is where I get after Gould and Eldridge, because basically the insinuation is that these evolutionary events happened so quickly that we are not likely to find them in the fossil record. And if we look at the fossil record we can see we get these great picture windows but we don’t get much transformation in between. Therefore we probably aren’t going to find them. And I’m saying, “Well, we’ll never find them if we don’t know how to look.” In places where you actually go out and spend some time looking, and in places where the resolution might be a little better in the fossil record, we do find things that look like transformations.

Skeptic: Is it possible they are finding transformations and force-fitting them into one of the two categories as opposed to seeing it as a 1.5.5.?

Horner: It’s possible.

Skeptic: This would end one of the creationists’ great arguments; every time Gish asks for a transitional form and you give him one, he then wants two transitional forms, so you give him two, and he wants four, and it never ends.

Horner: That’s right. But that’s because the Linnaean system doesn’t lend itself to transition. Another one of the problems that comes out of all this is that when you’re looking at this thing right here, that’s anagenesis. (See Figure 1.) This suggests straight-line evolution, as opposed to cladogenesis where you could end up having three taxa living together and still have one the ancestral form and another one the descendant form. In cladogenesis usually you don’t see examples of transformation; usually the best example of transformation is just size, starting with a mouse-sized animal and ending up with an elephant-sized. It’s obviously a transformation, but in cladogenesis you often see very different characters. The first animal might have big ears; the second might have a big nose—just different characteristics. You can see they’re all related to each other, but you have diversification. That is cladogenesis—you can’t organize it in any direction, you can’t polarize it. And that’s what we see in the fossil record. We see snapshots that have a lot of diversity. It’s hard for us to find transformations between them. But we occasionally do. You can hypothesize it, at least. In my book (p. 199, reproduced in Figure 2) I show an example of some dinosaurs that I think is really neat, but still very hypothetical. When I make a cladogram this way I’m doing the worst thing you can do to a cladogram, even suggesting a direction of evolution. They want these things to show evolutionary relationships but they don’t want to insinuate a director. They’ll be reading along and they’ll open to this page and probably drop it on the floor and kick it into the garbage can.

Here’s what I believe is a transformation: it is stratigraphically oriented in time; there’s a dinosaur called Styracosaurus that has three horns on each side of its frill and a big straight nose horn that is bound in 75mm old sediments. Then there’s the thing called Pachyrhynosaurus that has these two little curved-over spikes that is found in 68mm old rocks, and has this gnarly stuff all over the top of its head. These two kinds of dinosaurs were known for a long time and we went out and actually started looking at the rocks between where the Styracosaurus comes from and where the Pachyrhynosaurus comes from and found these three animals. They’re never found together—they are stratigraphically separated. The first one has one spike on each side with a straight nose horn; the second one has one spike. You can see they’re identical in their shields except the horns begin bending to the side, which we see finalized in Pachyrhynosaurus. And the nose horn seems to curl over, and in fact, it is curled over here and you can still see a separation between a gnarly thing here and the nose horn, then it’s finally fused. There’s a bigger buildup of gnarly stuff on the head—it looks like a transformation in both the shield and in the nose horn. And it’s enough of one so that it can be hypothesized. You can certainly see that this animal seems to be very closely related to that.

Skeptic: To test this hypothesis you would then predict that there would be something in between these. Further digging could then provide the experimental evidence.

Horner: We continue looking in all of these sediments for any of these things to overlap one another, because if they overlap one another, then we’re looking at cladogenesis. They might be different animals, but we have collected thousands and thousands of specimens and have considerable evidence of overlap. The problem is that in order to do this you have to have a lot of these specimens because there’s variation within all the populations. So what we do is go out and find a bone bed where we have lots of individuals and we look at how much variation there is within the population of that bone bed, of animals that have died all at the same time. And then we have boundaries on variations within the population. So if we go out and find another animal that’s not in that population, but still stays within the boundaries, we assume it’s part of that same breeding population. But if we go somewhere and find something that varies a little differently, then we tie it in stratigraphically. And we are starting to find things that are in between, but we don’t have enough of them to draw definitive conclusions.

Skeptic: I’d like to ask you a methodological question along those lines. If we have 12 T. rex skeletons, how do you know you’ve got the average, middle of the bell curve? How do you know you don’t have 12 individuals that are four standard deviations from the mean, or all females, all males, extremely large, extremely small. Is there a statistical assumption here that you’re likely to find an average individual?

Horner: We don’t even know that they’re all T. rex! This brings us back to the Linnaean problem again. None of these animals was ever found together. They were found in basically the same age rock, within a couple of million years, but there is no way to know that all 12 of these animals actually could breed with one another—that they were actually what we call “species.”

Skeptic: So you are skeptical of some of your own colleagues work.

Horner: We’re always skeptical of stuff like that because we have no way of knowing whether we’re dealing with a breeding population of an animal unless we find them all together. When we find a nesting ground, we’re pretty sure. When we find one of those big, massive bone beds, we’re pretty sure. But when we find isolates—when a T. Rex is based on all adults and we have no juveniles, we have no idea of the variations from juvenile to adult. In fact, there’s a dinosaur called Nanotarana [SPELLING?] which may be a juvenile T. rex. People are still arguing about that. I think it is a juvenile T. rex, but Bob Bakker thinks it’s a different animal and he gave it a whole new genus name—genus and species. He not only thinks it’s a different species from Tyrannosaurus, but he thinks its a different genus. This is the Linnaean system slamming us in the face!

Skeptic: It seems like you’re bucking up against a very human brain problem, since we do classify things. That’s one of the things we do, and gets us into problems of race and racism, over generalizations and hasty generalizations. We’re pattern-seeking animals that pus things into boxes.

Horner: But are we? Let me ask you a question. Is that a European thing or is that something that all humans do?

Skeptic: Well, I think it’s a human thing. I think cultures all over the world have certain patterns that they do, including “those guys are different from us (however the difference is defined) and therefore we should kill them, we should get rid of them or do something to them”.

Horner: The great apes do that, too.

Skeptic: I think it may be a product of a larger cortex. Maybe. It doesn’t mean that you can’t redefine it and say, “Let’s look at this a completely different way.” We are capable of learning.

Horner: I agree; I don’t doubt it a bit. But I would like people to learn evolution. I would like kids coming out of school to assume evolution so that we do not have to keep fighting it, and the Linnaean system stops them from understanding. It’s a barrier. It says “evolution does not occur.” All we have to do is get people thinking about how things are related, that they are related. From the creationist point of view things are not related to one another, right? They’re all created in one day. So my question to creationists is: “Why is it that some animals are more closely related than others?”

Skeptic: So you might show homologous structures to show relationships?

Horner: Yes. We know that at our family level, in our generations, we can see relatedness, and we know that when we’re looking at breeds of any animal we’re looking at relatedness.

Skeptic: Creationists call this microevolution. They’ll grant that microevolution happens.

Horner: We say, “Oh, wow, okay,” because we have put the species barrier there ourselves, and they’re saying, “Okay, I can see that evolution occurs within a species but show me an instance where it occurs between species.” As long as the species is something, then it’s a real barrier and I agree with them. Show me an example. Well, there is no example. But if we get the barrier out of there, they’re all over the place. Quit defining species as “something.” It isn’t anything.

Skeptic: So your new book, Dinosaur Lives, is far more than just another popular book on dinosaurs. You’re proposing some fairly radical ideas. You’re probably going to challenge your colleagues.

Horner: I hope so. I’m concerned about the fact that it’s been a hundred and fifty years since Darwin proposed the theory, and we’re no further along with the public. We’re probably behind.

Skeptic: The general statistics are: 45% of Americans believe that evolution had nothing to do it, 45% believe that evolution is true but that it was part of God’s creation, and only 10% take a strict naturalistic philosophy.

Horner: What does that say? Scientists have not done a very good job.

Skeptic: Is it the problem of scientists or educators?

Horner: For the most part, most scientists are really in ivory towers. Many scientists don’t like talking to the public. What’s very odd to me is that a lot of people will complain about the ignorance in the schools, but those same people will not talk to a teacher. Seems a little odd. And it’s not kids but teachers we’ve got to teach. When you go over and talk to some of the teachers, you learn that a lot of people become teachers because they like kids, not because they want to teach.

Skeptic: So this is why you publish with a major trade house and make countless appearances on public television. This is part of your philosophy of science communication.

Horner: Certainly. And one of the things I talk about at great length in the book is that it’s okay to be wrong. As scientists, we should take a pledge that we want to know the truth. We want to know what’s right, rather than wanting to be right.

Skeptic: What is it not okay to do?

Horner: It’s not okay to keep arguing with people who present evidence to show that your pet theories are wrong. Let’s show the general public that it’s okay to be wrong in science. Look around at the general public. They make a big deal out of it when someone shows that someone else is wrong in science. Why is that? It’s because people think “scientists are always right.”

Skeptic: And in your 30+ years of doing paleontology, where have you been wrong?

Horner: I’m wrong all the time! I just hope that one or two of my theories will be right.

Skeptic: You just throw stuff out there and see what sticks?

Horner: I hope I add a little data to it, but yes. There are two ways to do it. You can either work all your life and present one theory that you’ve tested and retested until you’re pretty sure it is right, or you can throw a bunch of stuff out there and hope some of it’s right. One of the things I have definitely learned is that I learn more when I’m wrong than when I’m right. When I learn that I’m wrong, then I’m pretty sure I have the right answer. When I think I’m right, I never know if I have the right answer. That’s sort of an interesting paradox.

Skeptic: Can you think of some specific examples?

Horner: Almost anything. You can make a hypothesis and even in the midst of testing your own hypothesis, if you test it properly,—and I think the proper test in all cases is the null hypothesis where you believe something is true and you try to show that it’s wrong—you learn more than you do if you just set out to prove it is right. And I think that in paleontology we see it a lot. This Tyrannosaurus rex debate I think is a perfect example. I used to think Tyrannosaurus rex was a predator and with my students we set out to test it. Using the null hypothesis we started looking for evidence to suggest that it was not a predator. Well, as it turned out, no one had ever demonstrated that it was a predator. So we started looking at the evidence, and everything started falling toward T. rex not being a predator. Scavenger is an alternative.

Skeptic: Could it be both? Hyenas do both scavenging and they hunt in packs. Lions do some scavenging.

Horner: The problem I have with that is that it’s okay to be both if you’re adapted for both. But what if you’re not? T. Rex has stereoscopic vision. As it turns out, all carnivorous dinosaurs do, so it’s a primitive character. Why would you select for not having it if it isn’t bothering you? It doesn’t make any sense to lose that characteristic—you’re not going to evolve away from it. It hasn’t evolved just for T. rex. There’s a duckbill dinosaur that has a tail bitten by a T. rex. There’s no question about it, a T. rex bit the tail of this dinosaur and advocates of predation say, “Here’s proof—a T. rex bit this dinosaur.” Well, one T. rex bit that one duckbill. It’s not like it’s a character across the species. And it bit in the back of the tail. You’re not going to kill an animal by biting its tail!

Skeptic: But they don’t have teeth like scavengers, do they?

Horner: T. rex has the most powerful jaws of any animal that has ever lived. It has round, bone-crushing teeth and you can see it took a lot of power to bite into that Triceratops. There are some other big, meat-eating dinosaurs like Carcaradontosaurus and Gigantosaurus that have very laterally-compressed teeth with serrations. Laterally-compressed teeth are not good for ripping; they’re good for cutting meat, but they’re not good for crunching bone. So T. rex and Gigantosaurus were eating different things; one was cutting flesh and one was crunching bone. Predatory dinosaurs don’t need to crunch bones. You get your prey, eat what you want of the meat, then you’re done. Scavengers crunch bone. Who needs the stronger bite? Do you need a stronger bite if you’re eating beef jerky or fresh steak? No question. Hyenas have the most powerful jaws of any animal around and they don’t utilize those powerful jaws to take down prey. They use them for scavenging.

Skeptic: Most predators sweep the legs of their prey with their front legs, which T. rex does not have.

Horner: Cats catch their prey with their arms. They reach out and grab it. There’s no way a T. Rex catch anything unless it catches it in its mouth. And I don’t care what anyone says, two tons of anything moving around in your mouth—I don’t care how big your mouth is—is not going to do your mouth any good! No matter how round and powerful your teeth are, you’re going to get them torn out because whatever you are trying to catch doesn’t want to be caught. Predation is very dangerous and it doesn’t work very often. Even a cheetah gets its prey one out of 10 times. That means nine times out of 10 it fails.

Skeptic: So the assumptions we made about that are probably from this typological thinking—it must be a reptile, therefore it must be a predator.

Horner: Right. But you know, scavenging is the most advanced and most specialized way of acquiring meat. When a predator takes down its prey, the prey is fighting for its life and will do anything it can to kill that predator—and sometimes predators do get killed. A good scavenger just needs are to chase away whatever else has already got the prey, and so size may be real important to a scavenger. When you’re going to get that carcass the animal that has the carcass is not going to fight for its life to save its food, so it’s not as dangerous.

Skeptic: Certainly T. rex would be intimidating to other scavengers.

Horner: That’s right—scary-lookin’! I’m not saying I’m right; I’m just saying it’s a hypothesis. It came out of testing a null hypothesis and we ended up getting a lot more data.

Skeptic: This is a perfect example of a historical science at work.

Horner: Yes.

Skeptic: What does the study of dinosaurs teach us about the tempo and mode of evolution? Can you see long-term trends of increasing brain size, increasin g body size, or increase of behavioral complexity? What kinds of trends do you see? You don’t seem to see an increase in brain size, for example.

Horner: No. That seems to be a mammalian thing. We certainly see trends toward gigantism in all animals and in all plants.

Skeptic: What is the runaway effect of size in dinosaurs?

Horner: Gigantism is interesting—why animals get big. I assume it has to do with the arms race theory: the plants are getting bigger, therefore the animals get bigger. I think that makes sense. Your prey is running faster so you have to run faster. Basically, all we are is mobile stomachs.

Skeptic: Not selfish genes?

Horner: No. We’re not selfish genes. I think the proof that we’re mobile stomachs is in the slime mold. The slime mold is really a single-celled organism that travels around and then when they run out of food they all gang together and they make this “moving stomach” that travels somewhere else to find something to eat, and when it does it builds its stock, makes a bunch of single-celled organisms again, and goes about its business. That’s a perfect example of creating this mobile stomach to get from one place to another. It’s not very mobile when it’s just single-celled organisms going around to get something to eat, but when food resources get short, then the way to get somewhere is to be a metazoan, in effect. It creates this metazoan structure to move its stomach somewhere else. I see that that’s what we are; we’re just big giant slime molds—just big mobile stomachs going from one place to another. That’s the bottom line; some of us just have bigger brains to get our stomachs from one place to another. The whole idea is just to eat.

Skeptic: Maybe a large brain is just a runaway arms race.

Horner: Absolutely.

Skeptic: On another controversial subject, I understand that you don’t “give a shit WHAT killed the dinosaurs.”

Horner: Hey! How’d you know that?

Skeptic: It’s stamped on the title page of your new book in red ink! There is a book out called The Great Dinosaur Extinction Controversy by Charles Officer and Jake Page, who are skeptical of the impact theory, saying that the iridium level is not at the right place. They feel that this theory has been hyped by the media way too much and before the data allowed it to be played out among scientists.

Horner: I talk about that in my book, too. In almost all of science, we are very interested and we always try to base all our conclusions on positive evidence. We disdain negative evidence, except in this controversy. No one ever found a dinosaur at the K-T boundary. There’s never been one found. Someone found a footprint not too long ago, like a foot below the K-T boundary. Big deal. A foot below the boundaries still isn’t the K-T boundary. Find some at the boundary; then you have some positive evidence. And it can’t just be bone fragments; it has to be an associated or articulated skeleton. Otherwise, there’s nothing to say that it hasn’t been transported and redeposited. There was a group I mentioned in the book that wrote this paper in Science about how if you look at the formation that has the K-T boundaries in it, that if you divide it into three parts and look at the bottom, the middle, and the top, that there really is no change in the number of taxa from the bottom to the top. But, they’re lying with statistics, basically, because they couldn’t identify things at the species level, so they identified things at the family level. And they showed that there are all the same families at the beginning that are at the end. Big deal. So maybe there’s 15 species at one level, then 10 at another, then five—then there would be a big difference. My suggestion is that we just look at the world at the phylum level, then we don’t have any extinctions at all! This is the kind of “science” that pulls the wool over the public’s eyes.

Skeptic: This sounds like theory driven data collection.

Horner: Yes. That’s exactly what it is.

Skeptic: Do you think the jury remains sequestered on it?

Horner: It doesn’t matter what did it. Maybe that did happen. But if everybody sat down and attempted to test the theory, using the null hypothesis, you’d never end up with any information to suggest that a meteor killed the dinosaurs. So, how come we do science everywhere else but here?

Skeptic: Maybe it’s this fascination with big things. What could be bigger than an impact on Earth?

Horner: Right. We like catastrophic stuff! Look at all this stuff we’ve been doing lately—volcanoes, asteroids, oooohhh, scary stuff.

Skeptic: This is yet another example of your somewhat heretical or unorthodox way of doing things. Would you consider yourself a rebel, a heretic?

Horner: I don’t know. I’m just having fun. I set out to do what I wanted to do.

Skeptic: Which was?

Horner: To dig up dinosaurs.

Skeptic: For what purpose? What were you looking for?

Horner: I don’t know. I’m driven to do this. To dig up dinosaurs and interpret them. That’s all I’ve done. I flunked out of college seven times.

Skeptic: You’re being modest, because you haven’t just dug up things. You’ve created a whole new research program of inferring behavior from fossils. That’s something you’ve pioneered.

Horner: People always said, “You can’t do behavior”, because you do behavioral studies by observation. Right? Well, I went out and was able to hypothesize things based on not observing behavior. I was going against the wave, the trends—against a lot of things. But if I hadn’t been able to demonstrate that, then it would have been okay. I didn’t set out to pioneer anything.

Skeptic: Why should we fund people who dig dinosaurs? What’s in it for society, to understand dinosaur stuff?

Horner: I get this question from almost every reporter and I know you understand the answer. Usually I don’t answer it because the people who ask the question will not understand the answer. You know as well as I do that there are a whole lot of people out there who do want to know the answers to questions about the prehistory of our planet. We try to justify it sometimes by saying, “The key to the present is the past.” It may or may not be, but the answer is “We want to know.” A lot of us just have to know. It doesn’t help us feed these roving stomachs of ours…

Skeptic: It’s food for thought.

Horner: But food for thought doesn’t feed the real stomach and that’s what I think is the curious thing. Our curiosity. How did nature select for our curiosity? That’s what I like to know.

Skeptic: My answer is that humans are story-telling animals. All cultures everywhere in the world have myths. This is our myth, our story. It’s different because there’s a method to it, but it’s another story in which put ourselves in the context of this whole thing.

Horner: What makes us human? What is it that makes us different from all the other animals? We can talk about culture, or being able to think in the distant future, or being able to plan. Another is that we can think into the distant past. Our brain is what allows us to do that—to imagine into the future and the past. And that may have adapted just for the simple reason of acquiring food. “Now what do I have to do to catch an elephant—next week?” It’s gettin’ cold out; I have to plan ahead. Maybe that’s all it is. So you do end up with a lot of baggage—a lot of quirky things and extra space in there when you can plan 10 years ahead or 100 years ahead.

Skeptic: Given our life span of 60 to 70 years, the idea of thinking back millions of years is inconceivable. Maybe that’s part of the problem of teaching evolution.

Horner: It’s only a number.

Skeptic: But it’s a big number.

Horner: Very few people can imagine a million, whether it’s a million years, a million miles, or a million dollars. So to say hundred million or a billion, it doesn’t make any difference.

Skeptic: With that I thank you. That is not the interview at all that I expected. It was a hundred times better!

 

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