#480 – Dave Hone: T-Rex, Dinosaurs, Extinction, Evolution, and Jurassic Park

Dave Hone: If you put Giganotosaurus T-Rex in... just look at the robusticity. Like the front of the snout of T-Rex is all bone. And yet the major openings is a thing called the Antorbital Fenestra, the opening in front of the orbit. It's absolutely massive in Giganotosaurus. It's like half the skull. The opening at the back of the skull is much bigger. The opening in the lower jaw is much bigger. And actually the jaw, what you can't see side to side is much thinner. So the heads are the same size. And as animals, they are about the same linear dimensions. But you can just see there's just way more bone in the T-Rex. ... So you need this kind of structure for the power that Crush has. So one of the big things tyrannosaurs have, and this goes all the way down to the earliest tyrannosaurs were like our size, like little ditty things like 2, 3 meters long, be a meter and a half tall. But they have fused nasals. So the pair of bones that in us, there's not a lot there, but obviously in something like a dog or something like a baboon with a long nose, it's like the whole top of the snout. And there's two, one each side. In tyrannosaurs, they fuse together. So they form a solid bit of bone. So the whole top of the nose is solid. And then that makes it very strong. And with that giant head, with all that extra bone and then all the extra musculature attached to that giant head, they've got this uber powerful bite and the ability to just chomp through basically the thing it wants to.

Dave Hone: We're pretty confident that the bite marks are sitting on top of erosion. What does that mean? So it means that the animal had died And it was found in sand covered, but in what would have been a river channel. So this animal has died, washed downstream, ended up on a sand bank. The sand is whipping past because I've been in a sandstorm in China and it is not fun. And that's starting to etch some of the bones and damage them. After that, you're getting bite marks coming in. So that can only be scavenging. That thing has been dead and sitting out for days, possibly weeks. before something came along and chewed on it. pretty much can't have happened any other way. And you have to take these really subtle signals to reconstruct the story. ... And then it's got these, actually, T-Rex has really small teeth at the front of its mouth, right in the front where our incisors are. They're called incisiform teeth. They look like incisors. They're A fraction of the size of the big ones. And they've got a really weird flat back. And that's what these are. It's hidden this with the front of the mouth and pulling. And that's mostly for eating. And that's why it's just on the delta pectoral crest because that's where all the muscles are. So it's, I always liken it to getting something like an Oreo and you take the top off and you scrape the cream out with your teeth. I think most people have done that. Right. But that's what it's doing. So it's got this little row of teeth and every where you get lots of muscle, you get little rows of teeth together. So there's different bite marks for sort of fighting, killing, and then there's different bite marks for eating.

Dave Hone: They're relatively efficient. compared to a lot of other things, and particularly compared to the herbivores. So that means they're probably looking at long distance rather than speed. And that makes sense, because even though the kind of stuff we're talking about, like I said, maybe they're getting to 20, 25 miles an hour, that's pretty quick, but some of the smaller stuff is going to be a lot faster than that. And remember, that's a real upper estimate. They're probably not that quick. Because they're just jogging after you. Right, but they've got they've got the distance. So yeah, so it's much more hyena or wolf-like strategy than like a cheetah going for hyperspeed or a lion going for a relatively quick burst and it either gets you or it doesn't. ... I think it's either or some combination of being nocturnal. So it's relatively easy to sneak, isn't quite the wrong word, but approach things to cut the distance down for your initial strike and then just running them down.

Dave Hone: I've jokingly written a couple of times about how all science funding in the world should go to paleontology. And the idea being that like, yeah, if you want to investigate black holes or neutrinos or chemical crystallography or panda genetics or whatever it is, You can do that any time you want. Like that, that's not going to change a million years from now as it will from tomorrow. But fossils are in places that erode and if we don't dig them up, they're gone. So we should dig all the fossils up now and then we've got forever to study them. But if we don't dig them up now, who knows? maybe there was something twice the size of T-Rex and it sat on a hillside for six months and then the wind got to it and it's gone. And that was the only one that ever preserved. Well, we'll never know now. To be clear, this is a joke. I'm not suggesting we should stop doing cancer research and physics and other things, but it is, we're in a fundamentally different field where our science is literally disappearing.