T-rex Much Slower Than Thought
ANDERSON COOPER, CNN ANCHOR: A new report published this week threatens to take a bite out of the image of the famously fierce T- rex. A Stanford University researcher is challenging the theory that the T-rex could run 45 miles per hour, saying it was more like a lumbering 25 miles per hour at best. CNN's Chicago Bureau Chief Jeff Flock is at the Field Museum, home to a T-rex named Sue -- hey, Jeff.</s>JEFF FLOCK, CNN CORRESPONDENT: Anderson, good morning to you. I don't think we can get any closer to the T-rex than we are right now. Take a look. You talk about fierce. You can almost touch the teeth here. This is the biggest and most complete skeleton of a T-rex that has ever been found. It is called "Sue," although we are not sure if it is a boy or a girl. It was found in South Dakota. It is now here at the Field Museum in Chicago, where it has already been viewed by -- I don't know, I guess it is fair to say thousands of folks, like the experts that I am joined with this morning -- where are you from, by the way?</s>UNIDENTIFIED YOUTH: I'm from Chicago.</s>FLOCK: Good. Well, that's good. You told me you like dinosaurs. How fast do you think this guy could run?</s>UNIDENTIFIED YOUTH: About as fast as an elephant.</s>FLOCK: Well, you know what, that's what the experts say. We're going to go over and talk to one of experts from the museum in a moment, and that's what they tell us, it may be as fast as an elephant, which -- do you remember that movie -- who saw "Jurassic Park?" Anybody see the movie? Put your hands up. Okay. Do you remember what the T-rex did in that movie? Does any body remember what the T-rex did in the movie?</s>UNIDENTIFIED YOUTH: He chased the people in the car while they were driving.</s>FLOCK: Right, and it was running pretty fast, wasn't it?</s>UNIDENTIFIED YOUTH: Yeah.</s>FLOCK: Do you think it could really run that fast?</s>UNIDENTIFIED YOUTH: So, so.</s>FLOCK: What do you think?</s>UNIDENTIFIED YOUTH: Yeah.</s>FLOCK: You do think it could run that fast?</s>UNIDENTIFIED YOUTH: Yeah.</s>FLOCK: Okay. Well, as we were talking, they're now saying it probably couldn't run that fast. But you know what, I want to bring somebody who is an actual expert over here. I've got Bill Simpson over here. Now he is one of the guys who helped put this whole skeleton together, and he's -- don't want to interrupt him (ph), he's talking to -- giving a little lesson to the school kids this morning. Give me some sense of what you think about how fast this dinosaur could run, this is no big news to you, correct?</s>WILLIAM SIMPSON, DINOSAUR EXPERT: No, it's not. When we first got Sue, we were telling people that we didn't think the animal could actually break into a run. It could do a fast walk at something like 10 to 15 miles an hour. This new research basically confirms what we were suggesting. If they could break into a run, they still couldn't run fast. They still would have been limited by -- at maybe 20 to 25 miles an hour, and that's really pushing it, but...</s>FLOCK: So they could clearly outrun people. Not that there were people there, but I mean -- so, give some people a perspective of how fast this would be.</s>SIMPSON: Well, it is interesting, actually. The predicted range of speed for a T-rex is about the same that you see for people. An Olympic sprinter can go about 25 miles an hour, which is what the best guess for the top speed here is. I could probably 10 to 15 miles per hour, running as fast as I could. So, the human range is about the same as that for T-rex.</s>FLOCK: What have you been talking to the kids about this morning?</s>SIMPSON: We've been talking about how Sue might have died, and whether Sue is a female or not, and whether Sue was a predator or a scavenger.</s>FLOCK: Yeah, that is another big question that is part of this research, is whether or not -- what do you know about that? Tell me everything you know about that. Who wants to tell me everything they know about the T-rex? Yes, go ahead. What do you know?</s>UNIDENTIFIED YOUTH: Well, they're big and fierce and you wouldn't want to mess with them.</s>FLOCK: Right. That's the notion, that they are fierce and that they ate other dinosaurs.</s>SIMPSON: Yes.</s>FLOCK: We don't know that for sure, do we?</s>SIMPSON: We don't know it for sure, but, you know, there are no modern predators that don't do both. Eat live animals and carrion, dead animals, so I'm sure that Sue was the same way.</s>FLOCK: Follow me around here, if you would, Bill, because I want to get a sense for how you determine these things, how fast the doggone thing could run. All you got is bones here. How the heck do you know how fast it could run?</s>SIMPSON: Well, we've number of different parameters. As you say, we know the bone lengths, so we have got that. We can take a guess at the posture. That is very important, actually. The different postures affect the results a lot.</s>FLOCK: Because this is a two-legged creature, correct?</s>SIMPSON: It is a two-legged creature. You can have the legs very erect, very straight, like an elephant, and then you don't need so big a muscle to hold you up. But if you have got the legs bent as in a running pose, then you need a lot more muscle mass.</s>FLOCK: And the other thing about these things. Two-legged creature, it is running, if it falls down -- I mean, two-legged creature can fall down fairly easily, right?</s>SIMPSON: Oh, as we all know, if we trip, we fall down. Now, with a four-legged creature, if they trip, they're unlikely to fall. A 12,000 pound creature tripping and falling, that is a disaster. It's going to break bones.</s>FLOCK: In fact, I'm going to ask Bill, if -- if you could take a look -- look at those ribs. We were talking about this earlier. Those are breaks in the bones in that rib cage there, correct?</s>SIMPSON: They are healed breaks, that's right. That is an injury that the animal went through, and in fact, the shoulder blade over here shows the same thing. So, there was a big injury to this area of the chest and shoulder, an injury that the animal survived.</s>FLOCK: So that might argue for -- if it fell over, that's potentially -- you don't know, but what the break could have come from.</s>SIMPSON: Yeah, we really don't know what caused that break. I almost wonder that if an animal like this fell over, it would be a much more massive break. The damage would be something that it might have not survived.</s>FLOCK: Right. I'm fascinated by this, Anderson. as I bet you are. I don't know if you are a guy who likes to poke around with dinosaur bones or not, but what do you think?</s>COOPER: I thought it was pretty cool, Jeff. I actually didn't realize that the T-rex and I had so much in common. The muscles on my legs are so big I often have difficulty running as well.</s>FLOCK: That's right. You have got what, 80 percent, of your muscle mass in your legs, is that what it is?</s>COOPER: Pretty much, yes. It is clearly not in my skinny little arms.</s>PAULA ZAHN, CNN ANCHOR: Hey, Jeff, that's why you never see a wide shot here on</s>AM. COOPER: That's right, we don't want to scare the viewers.</s>FLOCK: I know, when we saw you in the park the other day, I thought we were going to get lucky, but no, we did not.</s>COOPER: Are those kids disappointed to learn that the T-rex couldn't run as fast as maybe some of them thought?</s>FLOCK: You know, that's a really good question, and I do want to ask you, I mean, we were talking, and you said you think it runs as fast as a elephant. Are you disappointed that it didn't run as fast as maybe in the movie?</s>UNIDENTIFIED YOUTH: Yeah, a little, because I thought that they would be more dangerous than we see them now, in the movies.</s>FLOCK: You would kind of like it to be that way?</s>UNIDENTIFIED YOUTH: It looked so neat.</s>FLOCK: Would you have liked to have lived during that time?</s>UNIDENTIFIED YOUTH: Well, not to really live to see some of it on TV, because I wouldn't want to get eaten.</s>FLOCK: Truer words -- smarter words were never spoken. I don't want to get eaten, either. Thank you. There you go, guys.</s>COOPER: All right. Jeff Flock -- Jeff, thanks a lot. That was a really cool report.</s>ZAHN: I tell you, Anderson, I don't know whether Sue was coming at me at 25 miles per hour or 45 miles per hour, I would have gotten out of her way. TO ORDER A VIDEO OF THIS TRANSCRIPT, PLEASE CALL 800-CNN-NEWS OR USE OUR SECURE ONLINE ORDER FORM LOCATED AT www.fdch.com