How the Tyrannosaurs Ruled the World – with David Hone

thank you very much it really is a pleasure to be back at the Royal Institution this is a lovely place for me to come and I'm very excited I'm Dave hone I'm a paleontologist at Queen Mary University and this which you've all seen down the front is Queenie this is our Tyrannosaurus I'm afraid it's not a real one this is a car so this is a copy of an original which actually at the Smithsonian in Washington in the US but we're lucky enough to have her and bring her along and we'll be using her at various points in the lecture everyone knows Fran asaurus everyone is familiar with Tyrannosaurus it is probably the one dinosaur that absolutely every single person can name and it's a fascinating dinosaur it has an enormous amount of kind of cultural well baggage as well as excitement attached to it but actually from a paleontological point of view it is a really exciting and really interesting animal and in fact it's become what we call a model organism in biology that is it's become an animal or an organism which is well studied and so we know awful lot about and arguably we know more about Tyrannosaurus than any other dinosaur and therefore you actually tend to get this kind of weird positive feedback because it is something that we know an awful lot about if you as a paleontologist - starting a new study or a new project you're going to pick an animal that you already know a lot about so people tend to focus on Tyrannosaurus so they do more work on it so we know more about it so we do more work on it and so our knowledge about Tyrannosaurus in particular has kind of accelerated away from the other dinosaurs and it's become extraordinarily well known and therefore very very important for us but what people often don't realize is just how much we have there's this kind of idea that all our dinosaurs are very fragmentary and things are only known from a few little bones here and there and that is true for many species of dinosaur we often have only a single specimen it's very fragmentary we only have a few bits but trying to source that's really not true at all here are just four that are known and you can see here that each of them is varying degrees of completeness some of them have quite a lot missing some of them are basically complete the one down at the bottom there is known as su which is in Chicago and su is basically completed you can see a bit of the foots missing a few other little bits here and there but we basically have almost every single bone of su and it's also worth noting that they're not all quite the same just as not all of us are quite the same every individual is slightly different there are subtle differences in the anatomy the number of teeth are slight shape of a head the shape of the hands or the pelvis and things like this so there's really quite a few Tyrannosaurus specimens out there and that helps us learn more about trance ores you can see what the range of variation is you can see what big ones and little ones are like and things like this but you may be surprised like just how many we have so here is just a collection of the skulls that we have of Tyrannosaurus so here are eight different skulls queenie is actually in there at the middle down at the bottom and these are a whole bunch of trance or skulls from various different museums and even this really doesn't cover the diversity we actually have these are just ones I happen to have photos of there is about 20 good specimens of Tyrannosaurus give-or-take ones that are like the previous slide I showed and then when you start adding up all the other little bits we've got very fragmentary and incomplete skulls bits of backbone single arm single feet or bits of rib and things like this we have dozens of specimens of Tyrannosaurus so while it is true that odd dinosaurs are known from very little information we have to extrapolate a lot this is one where we have very large numbers of specimens often preserved in exquisite detail though there are some things we need to take care of one thing that's quite clear even from this photo is there are awful all different colors the one in the middle is a specimen in Canada which is called Black Beauty because the bone is almost black it's actually a beautiful specimen but your others that are brown very very pale colors and that's because they're all preserved in slightly different rocks they all have slightly different histories they all been squeezed and squished in various different ways at different times being underground for 65 million years often does quite a lot of damage to you and you can actually see this in various skeletons and skulls that are up there and so they're not all quite the same and we do need to be careful in how we piece together our evidence and build them up the other thing is so far everything I've shown you is basically an adult or at least near enough but we actually have a range of different sizes of Tyrannosaurus so these are three specimens that are in Los Angeles and at the top at the back we have basically a full-size animal so it'd be about the same size as Queenie down here so you can see just how big that would be and then off on the right is a kind of about half sized animal at least in terms of length in terms of weight could be considerably smaller and then down the front again is a tiny little one known as Chomper and their head is about this big 30 centimeters maybe it's a very young animal maybe only a couple of years old so we have a real range of sizes as well so it's not just that we have this whole big pool of giant bone crushing monsters although we have plenty of them we do actually have the equivalent of teenagers and even very young children though sadly today we have no eggs and no embryos we do have a lot of eggs for dinosaurs and even a few unborn embryos of various ones but not one for Tyrannosaurus or indeed any of the tyrannosaurs and any of the trainer Soares is a really key point because again everyone has heard of Tyrannosaurus everyone knows that name it is one of about 30 species of Tyrannosaur this is a big diverse group of animals it is not just one species t-rex it is in fact a whole group or what we've called a clay - an evolutionary group of animals and as we can see from here hopefully you can see quite a diverse sense of size and shape these little silhouettes are not done to scale and this is the complete family tree of them so far I say there's about 30 species because we don't actually know quite how many there are and there's a couple of reasons for this first of all play lis ontology is actually disagree on quite how you tell species apart this is a problem that plagues modern biologists to things that look very very similar to each other it can be very hard to say if they're one species or not they might have very similar genetics but quite different behavior or very different appearances and live in different countries but then their genes are almost the same we are looking back to at least 65 million years with most of the bits missing it's therefore a never-to-be very very hard to say sometimes when you have two very incomplete skeleton's if this is one species or two or if you have only a small group of very nice specimens maybe there's two species in there but we're not quite sure so i say about 30 because that's a number that probably everyone agrees on but they could easily be one or two more and we don't realize yet or one or two fewer and we need to revise some of our estimates but it's certainly really quite a diverse group not only that but tyrannosaurs really got around to ran asaurus itself lived in north america we have lots of specimens from canada particularly in alberta and the u.s. particularly in montana but it was wider ranging than this there's a whole bunch of bits down in central Mexico which may or may not be Tyrannosaurus they're very fragmentary but certainly about the right time and it would not be a big surprise if t-rex had a really big range across the whole of North America there's a whole bunch of Tyrannosaurus that lived in North America it's not just this guy we have things like albertasaurus from Alberta and Gorgosaurus and Daspletosaurus and a whole bunch of others we have a whole load from Asia it seems like Tarbosaurus ji Chang star anise a Leo Ramos and then going right back to the early days of trynna sauce we have things like clan long and D long what may surprise some of you to learn is we actually have two different species which are known from the UK if a little thing called Pro sir aster Soros and another one from the Isle of Wight called EA Tyrannis and actually Pro Ceratosaurus is one of the earliest of the tyrannosaurs so it actually sits here on this little branch which is actually called the Pro Sir Arthur saw today so it's an own little branch very early branch of Tyrannosaur that came off and diversified into a smaller for group and these are unique because they all actually have little crests on their head which will see better in the next slide but the emphasis I want to make here is just how many tyrannosaurs there are it's not just t-rex this is a hundred million years worth of dinosaur II and evolution the earliest tyrannosaurs that we have lived about 165 million years ago and the last of them including things like t-rex died with the great mass extinction at the end of the Cretaceous period right around 65 million years ago so conveniently in one way the trainer soars around for almost exactly a hundred million years so that's a nice easy figure and we have them on at least three continents there are suggestions of one in Australia there's a very fragmentary bit of a pelvic bone in Australia and there are some animals in South America which some people think may be an odd branch of the tyrannosaurs and if so in both of these cases then we have them on at least five continents and they work basically worldwide if we look at them in a bit more detail we start to see some differences crop up none of these pictures are quite to scale by certainly the one at the bottom is much bigger than the one at the top so the top animal here is a thing called guanlong from China and that name means crested dragon and as you can see there's actually this big expansive bone along the top of the skull it has this little bony crest which sticks up and we think this is probably some kind of signaling device so something basically to show off and say how big and strong you were and we can see there's some major transitions that happen with the tyrannosaurs we look back a hundred million years we see these animals are really quite small grand long is a very small animal maybe about two and a half three metres in total and about half of that is tail so you're not talking about a very large animal if we look a bit further down we see that there's a pattern starting to happen the arms are getting a little bit smaller a t-rex famously has these tiny tiny arms but if we look back to its earliest ancestors but you have great big long arms and tiny little heads and a little neck this is not what we think of when we think of tyrannosaurs but actually if we look over time we see there's these fairly obvious patterns of as we go through a small head becomes proportionately bigger and proportionally bigger that long thin neck becomes shorter and stronger the body becomes generally deeper and more robust the arms change from these great big long arms with great big long claws and the end and three fingers down to a shorter and shorter arm and then reduce finally to two fingers and at the same time the body is becoming proportionately big and as well though you can't see on this figure the teeth are reducing in number Tyrannosaurus and its nearest relatives things like Tarbosaurus from Asia basically have about 60 teeth things like D long and grin long some of the earliest dinosaurs have closer to a hundred so they're slowly cutting down the number of teeth they're getting bigger heads shorter necks a bigger body shorter arms and overall they're getting bigger and bigger and bigger and so this is what happens when you put together a hundred million years of evolution so here we have grin long again with these little crest knocking around at about three meters long maybe and here we have sue to the same scale which is in Chicago sue is probably about 12 12 and a half meters long and weighed right around seven eight tons so that's about two big elephants put together maybe three or four family cars in weight and this is still a biped with a head every bit the size of Queenie here and I can assure you cuz I've measured this I actually fit through the mouth so everyone who seen Jurassic Park if you want to know if you can eat a lawyer yes they can and into a single bite too you fit these things are absolutely enormous but this is what the change we've seen over 100 million years we've got massively massively bigger in size the head shrunk the next Shrunk the bodies got bigger and the arms are absolutely tiny just for comparison this is most of the forearm and hand of Albertosaurus silver the source lived in Canada around 70 million years ago so just before Tyrannosaurus it was a little bit smaller maybe around 10 meters or so and this is the falling bones the radius and ulna and the hand bones and you can see it's basically the same size as my arm for an animal that was perhaps 10 meters long and around 3 tonnes this is a tiny tiny reduced little arm and even though these claws look really quite vicious actually they're rather less curved and less sharp than we see in various earlier animals including guanlong which is just they're not actually really using them in the same way so those arms were really reducing away and becoming kind of less and less effective so I've introduced you to about 30 tyrannosaurs there if very very briefly indeed but how do we know they're all tyrannosaurs what actually unifies them together as a single group or we can confidently say this is one evolutionary played that we can put together well there's actually a couple of features let's show up quite well and we see these on every single Tyrannosaur one of them are the nasal bones these are the two bones that run along the top of the snout and they basically make up most of the nose and in basically all other dinosaurs they're a pair one on the left and one on the right and if I hold up here my little velociraptor so again the nice Jurassic Park reference this is not going to fight this this is how big velociraptor actually was I can pretty much fit this skull into just the nose it's not really a fair fight but actually if we look at the nasals here you can see there's two different bones top and bottom with a very obvious line separating the two but in the tyrannosaurs in Queeny and if we go back to the slides you can see on the skull there there are actually a solid block they're fused together in the middle so they have this lovely solid pair and that makes the skull very very solid indeed and this points to an animal with a very very strong bite even in small things like guanlong and d long that were very early on they had fused their nasal bones together and made a really solid skull there's no other carnivorous dinosaur that does this we see that throughout the group the other thing that they have is the shape of their teeth and in particular the teeth at the front of the mouth so we have these lovely big biting teeth all the way down the sides of the jaw very very large very very strong indeed but if you look round to the front you can see that actually they're really quite small they're not very big at all compared to the side ones and they're all kind of scrunched together they're a little group kind of all forced up and this is unique we see these in the Tyrannosaurus and in nothing else and not only that but their shape is quite unique as well so if we can get this up on the camera hopefully we can see this here we go so this is another cast of one I see a very very long root with just a little crown at the top it's very very thick it's kind of short and fat but you can see the rear side is almost completely flattened off whereas the rest of it is really quite nice and rounded so if you cut this in half and look down on top it would look like a capital D so these are what are called the D shaped teeth of tyrannosaurs and if we compare that to the teeth of many other carnivore so this is a our saw you can see that actually this is very very thin and blade like on all sides and totally different in shape to what we have with the Tyrannosaur teeth and again this is what we see in all Tyrannosaurus we see this in the earliest forms right the way through to Tyrannosaurus they have these very very small D shaped teeth right at the front of the jaw and that gives them a series of unique adaptations which we'll get onto in a little bit of just how they function so this is one of the ways we can tell tyrannosaurs apart you ever find yourself in a museum or lost in the desert and you managed to find a new skull of a dinosaur and you see that it has fused nasals and little D shaped teeth at the front congratulations you found a Tyrannosaur so that tells us what we are but what makes them special why are they interesting and unique are there's a number of features and one of them actually is the kind of shape of the skull Tyrannosaurus is particularly exaggerated in this sense though it's true of the tyrannosaurs generally so here again actually you can see the beautiful fused nasal as you can see there's no line up the middle there absolutely solid and here we're looking straight up the nose exactly the view that the audience have at the front here straight down for those two lovely big eye sockets and what happens when you fill in those I sockets you get this which is always good for a lot but it tells you something about the shape these are binocular animals these are not animals with big forward-facing eyes that are looking at things this means it's a carnivore it is judging distances it wants to know how far away it is from something that it is very interested in and this is a totally different arrangement of the head to what you would see in herbivores sheep cows rabbits they all have eyes on the side of the head because they want to look around them and want to avoid things that are going to eat them not something that is coming to be eaten but what you can see here as well though is also the size of those eyes the eyes of Tyrannosaurus are absolutely enormous they're going to be about this big that's how big an eyeball you need to fit in the skull now even though this is absolutely huge it doesn't look very big on the head simply because the head is so absolutely enormous ly outsized but if you're looking at eyesight one of the critical factors as to how good your eyesight is is just how big your eyes are this is whether or not you want to have a very refined sense of vision or whether you want to see in the dark so you can think about things both like vultures and owls vultures have extremely good eyesight l see very well in the dark either way you want a big eye and basically the bigger the eye you have the better your vision and it's all about absolute size not relative size so actually Tyrannosaurus believe it or not has the largest eye that we know of for any terrestrial animal ever this is an animal with superb eyesight so just to bust another Jurassic Park era myth this is not something that can't see you if you don't move this has got the greatest eyesight of any animal on land ever that we can know of yes it does suggest it could see you quite well and sitting still is probably not a very big defense but also on top of that the skull is extremely wide if we compare Tyrannosaurus to other large carnivores this is a thing called Carcharodontosaurus which is actually nearly as big as t-rex this is a very very large animal indeed and you can see the skull is extremely narrow the eyes still point forward but the skull of the hole is very narrow it is a similar sized skull to the one we see on the right which as you can see is slightly crushed this is one of the problems of working in paleontology even things like whole Tyrannosaurus skulls tend to get crushed after a few tens of million years but you can still see the overall width of that skull is very considerably wider this is a very very broad head indeed and this is one of the other trends that we see the early trainer sores not so much but by the time you start getting to the really big guys they have this very very very broad head if you're getting very big it can take quite a while so su 12 plus meters seven eight tons maybe and tyrannosaurs actually grew very fast dinosaurs actually generally grew quite quickly to get to a dot size but even within them Tyrannosaurus itself actually is a bit of an outlier if we look at some lovely growth curves here we can basically see that several nearly Tyrannosaurus sized animals Daspletosaurus dogosaurus and Albertosaurus all from north america took about 15 years or so maybe 20 years to get to full size and that was 2 or so tons some of the bigger ones are probably rather larger Tyrannosaurus however goes through this beautiful growth spurt around 10 to 20 years where it absolutely balloons gets very very large very very quickly so this is an extremely fast-growing animal and that gives you a real sense of you know just what's kind of going on metabolically to grow at that kind of rate I mean this is the maximum growth spurt that humans have sustained over multiple years and in the range of things that are tons in weight but what's really quite neat is that they don't just grow fast and grow very big but they actually change shape quite dramatically as they do say this perhaps isn't so much of a surprise if you think about humans if you think about any animals most things actually change shape a bit as grow you know we famously think of puppies and kittens and babies as having big heads and big hands and big feet and then you kind of grow into them as you grow up so it shouldn't be a big shock that dinosaurs change shape as well but it's noticeable just how much they change when it comes to the Tyrannosaurus so this is a skeleton on the right which is known as Jane and Jane is as you can see about half grown at least in terms of length so about 5 6 meters long or so and yet the head is absolutely tiny compared to that of a full-sized Tyrannosaurus so whereas we think of babies usually as being big-headed and then it takes a while for them to you know your body kind of grows into your head or vice versa we see here that actually the young one has a small head and by the time it's got to full size its head has got proportionally much much bigger we also see that Jane though Tyrannosaurus generally have long legs Jane has really quite long legs a really quite slender body and quite a slender neck so this points to an animal that's doing something actually quite different the head is built differently the legs are built differently this is an animal which is running in a different way and probably feeding in a different way so we're not just seeing them growing and we're not just seeing them changing in shape but the implication for this is that they're also fundamentally changing their ecology and their behavior as well and therefore actually in some ways you could treat these as two different species the big adults are living and hunting and acting in a way that the smaller juveniles aren't and they're shifting from one to the other as they grow this has not actually got unusual we see exactly the same thing various snakes lizards crocodiles and other relatively slow growing animals that are around today but it really shifts the dynamic of how we think of these species interacting with others in an ecosystem when we know that they can have such dramatic changes one thing that's really important here is these legs and in particular these feet because this is another really special adaptation that we see in Teran and this goes by the magnificently tongue-twisting name of the octo metatarsal e'en condition I know it's lovely but actually it's really worth having a word like that because it's easier to say octo metatarsal alien or at least one uses when you set it quite a few times than it is to say that special condition where the weird metatarsal is kind of shrunk at one end but wide at the bottom and it's kind of pinched between the other two and it changes how the foot functions because that's what it means but octo metatarsal alien is actually easier so if we look at a Tyrannosaurus foot this is the foot from a nearly complete or a nearly full size Tyrannosaurus it's a right foot so you have four toes the first toe what for us sorry it's a it's um sticks out at the back a little so it's almost like the dewclaw that you get on a cat or a dog and then three walking toes and these are the metatarsals the bane of the footballer we're all forever hearing about broken metatarsals so we walk on the flat of our feet we have both our toes on the ground and we have our metatarsals on the ground we walk across the whole foot the dinosaurs and indeed the birds and many other animals just walk on the toe so they've elevated the foot and they have the leather tassels or of in case of my hand metacarpals suspended if you like upright and this actually already automatically kind of extends the length of the leg it gives you a longer leg to run on so this is actually going to speed you up because it means you're taking longer steps for every pace but if we look to the middle what you'd see on most dinosaurs in fact the vast majority of them in particular the carnivores is the three metatarsals for the three running toes would all look like this they'd be lovely long big blocks nice vertical strips but we see here this middle one kind of vanishes and it's being crushed between the other two and it looks like it's kind of disappeared and not gets going to come out the back but actually it doesn't it really is being crushed and we can see that we can switch back up to the slides there we go so here it is this is the middle one and you can see the top just kind of vanishes it just absolutely disappears I've actually got a real one here so this is online from the Royal Tyrrell Museum in Alberta it's actually from another dinosaur it's not actually a Tyrannosaur but two or three different groups all evolved an arc toe metatarsal and you can see here totally crushed in this is where the other two would attach and if that shows up okay you can see the cross-section it's this tiny squished triangle so it really has completely crushed effectively that middle toe or that sorry that middle metatarsal and this is actually a really interesting feature because this totally changes how the foot moves if you can imagine you want to be a long-distance runner every time you hit the ground every time you take a step your bones are all slightly moving and that represents lost energy because if they don't what you actually tend to do is start compressing some of your ligaments and some of your joints and as you step off again that springs back and you get a little bit of energy back so what you really want to do is to minimize all of the movement you want to have everything as firmly and tightly together as possible because every little bit of movement is just wasted energy and if you do this with a lovely big wavy bone up the middle with two bones locking it in either side you're effectively holding the whole foot together and when we're talking about an animal that might be six or so tons every single footstep can potentially lose a lot of energy with the bones just see soaring either side of each other and you're having to hold them together if you lock them up into a single block that doesn't happen some of that energy will then go into your joints and you'll get it back on the next step and so this is an adaptation that we see in three or four groups of dinosaurs and they're all long-distance runners they're all very efficient over long distances they usually have very long legs a light bill they have a relatively short thigh bone which allows them to move the legs repeatedly and that makes them both quick and efficient over low and distances so despite the fact that a full-size Tyrannosaurus was clearly a very bulking animal they were also pretty fast the estimate speed estimates are really difficult for an animal that's been dead for 65 million years for which we have no muscles but barring all of that in mind something like a full-sized Tyrannosaurus was probably reaching speeds comparable to an Olympic sprinter only the difference is this is an animal which isn't specialized for sprinting it's specialized for long distance running so it's holding that speed probably for quite a considerable period of time you could not outrun this animal no chance not even beginning to and you also couldn't hide because it could see you very well as well this is a really really effective animal and more so than that it's really really effective because of the way its skull is built so here we have some beautiful CT scans of a pair of skulls a very very large dinosaurs indeed on the left once again we have a Tyrannosaurus and on the right we have this huge carnivore from South America called Giga notice source as you can see the scale to the same site in fact they're not scales percent they are the same size Giga notice Oris has a skull about the same size as tryna source but look at the difference in the amount of bone which is present in each of them Tyrannosaurus is basically this solid block yes it's got some holes in it but there's a huge amount of bone here and the lower jaw is almost entirely solid compare that to giga notice Oris is this really thin lower jaw with a large hole in it this huge anterior hole in the skull and a very large one at the back as well there's not a lot of bone there it's really quite thin in places despite the fact that this is a huge and powerful animal it has nothing like the build of a Tyrannosaurus it also doesn't have the fuse nasals which help make the skull even stronger and it also doesn't have the teeth if we can switch back to the viewer again I've shown you the little teeth at the front but now let's have a look at the big killing teeth down the side so this is a maxillary tooth so one of the big teeth down the side oh sorry can we flick up lovely thank you so here is one of the big teeth so this would be down the side of the jaw and look at this thing it's absolutely solid this is the crown here again with a very large root it's absolutely solid it's almost circular in cross section it's nearly as wide as it is long and again if we compare this this is a carcharodontosaurus from a slightly smaller dinosaur but there's the comparative width it is a fraction of the width and of course if you make something much much thicker you're going to make it much much stronger so this is a tooth which is extremely powerful perfectly capable of biting very deep and very hard into things even very very hard things I actually have sadly it's only the tip but I actually have a real Tyrannis or tooth here again this is online from the turul Museum you can just zoom in a bit and we go lovely so it's just the tip this is probably from a Gorgosaurus from Alberta this was found by one of my students last year when we were out in Canada and you can still see there's actually a little line of serrations along the back so even though they have this enormous kind of puncturing tooth they do still have a lovely little train of serrations along the back so there is still a cutting edge front and rear and again look at the cross-section very very rounded and extremely solid and powerful tooth so we have a super large skull in the big animals they have super large teeth and they're well built with lots of bone and various fused parts to give them enormous strength when you add that together you get an animal with colossal bite power more so than any other dinosaur that we know of and then you start seeing things like this this may not look like very much in fact it all looks like a bit of a but this is most of a Triceratops pelvis we're looking at it from underneath as if the animal was lying on its back we've only got about half of it so here would be the backbone here are various extensions and then the major part of the pelvis is here for a start a fairly large part of this is missing and it's missing in a rather suspicious way because it's got a kind of little serrated edge to it almost as if five or six big very strong powerful bitey things had knocked a hole in it and broken the end off you can guess what that might have been more so it's got a whole load of holes and gouges and grooves in it all of which are suspiciously very very broad compared to their length in other words they look an awful lot like the cross-sectional shape of a Tyrannosaurus and in fact the the researchers this is a photo from Greg Erickson in Florida they actually took some lovely liquid rubber cement the kind that the dentist used to take a mold of your teeth and they poured it into those holes and when you pull it out it's almost a perfect copy of a Tyrannosaurus their teeth are not just capable of biting deep into bones and leaving huge holes in them they're so good it they actually leave a mold of their tooth behind in a blunt of solid bone this is an extraordinarily powerful animal in terms of its bite power and this is an adaptation that we do not see in any other animal which is really quite nice now there's a really interesting aside to this study which is trying to infer what the animal was doing there was a famous debate which I really wish would be over but if it isn't over already I hope to demonstrate it as to whether or not Tyrannosaurus and the Tyrannosaurus generally were predators or scavengers now this is very actually hard to show because obviously seeing and identifying those kinds of behaviors in the fossil record is very very difficult it's very hard to come up with any evidence which will show it either way and Greg and his colleagues suggested that this may have been a scavenging event animals don't usually chew a part of very old pelvis unless there's not a lot of good going and that kind of implies that it was perhaps scavenging but it's very difficult to demonstrate that this might actually be the case it certainly could have been and I think it's quite likely but it's also true that things like leopards if they manage to kill a large antelope they'll spend several days eating on it and by the end they will be chewing on the last little leftover bits and that's not scavenging it's just taken them a long time to get through it what you really need to try and demonstrate that is in fact some kind of very special specimen where you could tell what the history of the dinosaur was before the Tyrannis or to it and I was lucky enough to be given the opportunity to work on one such specimen back in 2010 with my colleague Mohito watabe in Japan this specimen is actually from Mongolia though it's held in Japan and it's the humerus of the upper arm bone of a hadrosaur one of the duck-billed dinosaurs and what all these black arrows point to is various different bite marks along in fact this thing has been extremely well bitten by a large Tyrannosaur and this would be a thing called Tarbosaurus which lived in the Late Cretaceous of Mongolia and North China so there are big deep bites at each end and then this big flange of bone along the front here has groove of the groove off the groove after groove stored in it you can't see it too clearly there but if we go to this place up you can see here there's you've got three lovely little bites put together nice little grooves in the bone and another one here and here and here and here and here and here about 50 of them this is a huge number of bites but they're also quite distinctive because although this is clearly a very large animal we're lucky with some of the big dinosaurs that often they're the only large carnivore in their environment if you find a bone in Africa with a whole bunch of big bites on it from a large carnivore it's often hard to say it was that a lion or a leopard or a cheetah or was it a hunting dog or one of the various species of hyena with Tyrannosaurus you've often only got tyrannosaurs around so you kind of know what did the by even if you have no direct evidence and yet even though these are very strong and powerful bites that have gone into the bone the teeth don't appear to be that big and they're also really really close together and this takes us all the way back to our defining characteristic of tyrannosaurs they have this little cluster of teeth at the front they're all the same length they're all very close to each other and they're all really quite strong and solid and with these little flat backs and this is going to be perfect for grinding across the surface of a bone I suspect that everyone in this audience has at some time taken a custard cream or a bourbon biscuit and you take the top one off yes we all know this is going and you put it in your mouth and then you scrape the cream off yep that's what tyrannosaurs are doing and I know that's what they're doing because the interesting thing is if you flip this bone over the bites on the underside aren't in the same direction as the ones on the top so it is not biting top and bottom together and pulling because if it was all of the marks would line up they go in different directions and tyrannosaurs are not like us they can't move that yours like this they can only go up and down so they're just using the upper teeth and that's why you get this very distinctive set of marks that are large showing the teeth are large but they're very close together and they're all the same depth whereas if you look along the side of the jaw all the teeth are different lengths if they were doing this with the big teeth in the side of the mouth there'd be big spaces between them and one tooth would contact but then the next one shorter so it doesn't do anything it's only if they're using their upper teeth and drawing it along the surface when you actually get this effect it's also interesting that the only place they do this on the bone at least on the duckbill is this part here which is where all of the big chest muscles attach to the upper arm and they don't appear on other parts of the this animal was feeding selectively it's not some mindless big bone crunch it's not like you see crocodiles feeding where they just tear off big chunks of everything and bash it about and swallow it this animal only bit in a certain way on a certain part of the bone where it could get muscle this is a very careful feeder these animals can selectively choose how they bite and where they bite in order to feed and they have a suite of adaptations in the skull to allow them to do that they're really quite a specialist animal in lots of ways so this really tells us something about their behavior but there's another factor to this skeleton as well I've only shown you this one fall in bone but in fact that hadrosaur is known from an almost complete skeleton we have the skull the neck the ribs the legs the tail we've even got patches of the original skin preserved it is in beautiful condition but interestingly several several bits of it show evidence of having been damaged by water this is an animal that actually lived most in the desert but it was found in what we know was a fossil water channel and that had been partially buried and only one bone of this incomplete skeleton shows the damage and it's the upper arm it's the humerus but it's also the bone that was sitting uppermost so this animals killed over on its side an only bond bone was sat out and that they didn't show much evidence of water damage but it did show evidence of having kind of been beaten up by wind they do leave very distinctive traces on the bone when you combine this information it becomes fairly clear what must have happened we've seen what a Tyrannosaurus will do to a pelvis if it gets hold of it so why is it left this entire skeleton which even has skin left on it so must have had all the muscles and other tissues attached not to bite one bone 53 bites on it what happened was this hadrosaurid died somewhere else perhaps in the water and drowned washed downstream onto a sand Bank showing evidence of water transport and damage then being buried and only one arm was left on the surface then a Tyrannosaur fed up on it so now we know this is scavenging this animal was scavenged because it was dead before it was bitten so we can put one thing to bed did Tyrannosaur scavenge things yes excellent now the other half did they predate on things well here we have yet more hadrosaurs this time we have a pair of tail vertebrae so two bones from about halfway down the tail and they fuse together there's a major injury or illness here which has caused the bones to fuse are actually really quite common in various dinosaurs they have lots of little bangs in the tail and if you bash them up a bit they tend to form a big lump but in this case as you can see hopefully what the pencil is pointing to is a weird nodule in the middle that's a bit of a funny shape and so they x-rayed this and when you x-ray it first of all you can see the original join which is now sealed up between the two bones but then you can also see something which is a very different density and to the rest of the bone because it's a different color it works Cuse me and also has a fairly distinctive shape it's a shape we've all seen before it's the cross-sectional shape of a Tyrannosaurus teeth which is nearly as thick as it is long and slightly tapering at the back that's a Tyrannosaurus tooth which is inside the bone and the bone has grown over it that takes days maybe weeks possibly months to happen this was a hadrosaur that a Tyrannosaur bit into it pull the tooth out and lift it presumably because it got away and over time it healed it was a nasty wound lots of new bone form to try and heal up that wound and one of the things that it did was cover the tooth now technically that's not a predation event because clearly it survived but I think you'd be hard pushed to come up with many other explanations for why a herbivorous dinosaur had the tooth of a Tyrannosaur into its tail this also isn't the only specimen we have like this there's actually another specimen which has a Tyrannosaur - embedded in the lower leg and as yet another hadrosaur which has one of its tail vertebrae has the top broken off in a pattern which is very suspiciously similar to the shape that we saw in the Triceratops pelvis so in other words it looks like it's been bitten through so we have three different incidents here where it looks like a Tyrannosaur has bitten a herbivore and that herbivore has escaped but I really think we can fairly convincingly call this predation so we're tryna saw scavengers yes were tyrannosaurs predators yes they were both this is not a big surprise the vast majority of carnivores alive today are quite happy to hunt food down when they can but also to pick up a free meal when it's available we can begin to put the two together we're on the spectrum these things sit that becomes harder to say particularly when we've got the situation's we've seen where they're actually changing size and shape over time maybe some were better adapted for some jobs than perhaps others there's also another pattern that's feeding in here so these three specimens the one I've mentioned here and the other two and other with a tooth inside it and the other one the snap vertebrae they're all quite young animals maybe only about half size four hadrosaurs and in fact there are several evidence trynna sores with stomach contents where we actually have the fossilized remains of their last meal those are also of juvenile dinosaurs and these we also have a Tyrannosaurus coprolite does everyone know what coprolite is there are ongoing - let me hit written this is fossilized poo we have fossil poo for a Tyrannosaurus and it has bits of bone from baby dinosaurs in it now that's rather interesting that we have five or six of these records and every single one is a juvenile because what you always see in documentaries and films is you have to have a full-sized adult rhinosaurus fighting a big full-sized adult triceratops and that's a really bad idea because a big Triceratops is weighs about the same as t-rex and their horns are about this long it is an extraordinarily dangerous animal and anyone who's seen any of the great Natural History documentaries what's the one thing you hear on the voice over time over time the lion's target the ill the old and the young they don't go after big healthy strong adults because any major injury to a carnivore is generally fatal they will not be able to hunt and they're going to die so what do they target things they can get hold of easily that may not fight back that leads us to juveniles what's another big feature we know of dinosaurs here is a cluster of dinosaur eggs from central China they laid lots of eggs we have very large numbers of juveniles out there some of the bigger dinosaurs may have been laying 50-plus eggs at a time and may have laid multiple s nests in a year compare that to elephants that have one baby every four to five years an even larger dinosaur like a large hadrosaur may have had a hundred eggs a year for multiple years in a row there are an awful lot of small dinosaurs out there to be eaten and it's certainly a better option to try and tackle those than a lovely big adult which is also covered in giant horns or armor is much more dangerous it also fits with what we see in terms of general patterns one of the great offenses for animals of all sizes and shapes against predators is hanging around together in groups you're more likely to see some danger coming and it's very noticeable that we now have dozens of specimens of Triceratops all the adults are found on their own we've only ever found juveniles twice and both times they're in groups so the adults appear to be solitary they probably don't have too much to worry about in the same that a buffalo a rhino generally doesn't worry too much about lions but the juveniles are vulnerable and they're hanging around together so see a fundamental shift in the ecology of herbivores as a result of the threat of carnivores a couple of last things just to bring up about tyrannosaurs before we finish up this is part of the tale of D long if you remember back to the start D long is one of the early tyrannosaurs from China it's around 150 or so million years old so from the early part of the Tyrannosaurus it's just a bit of a tail so here's one tail bone here's the second tail bone and there's all these lovely little stripey bits on top those strike two bits are feathers tyrannosaurs had feathers along house feathers in fact the nearest relatives of the tyrannosaurs one group called the Compsognathus and another called the all of the - ors we know both had feathers and indeed all of their more recent relatives had feathers up to and including the birds there's a whole swathe of dinosaurs with feathers one of them is the Tyrannosaurus now when this was first found people were fascinated Wow serrano soars may have had feathers and the immediate criticism was okay but D Long's like tiny like D Long's two meters or so it's a really small little light animal it lived in quite a cold environment it needed feathers to keep warm but T Rex wouldn't have feathers once you get big you're going to need to have scales you're going to need to get rid of those feathers or you're just going to overheat so okay maybe D Long's got feathers but but the other trainer sores don't then a couple of years ago this turned up this is you Tyrannis and it may not be this clear but you Tyrannis is now known from three specimens and two of them were found together so hopefully you can see here is a head and a neck a back pelvis and a leg and one tail and then a second tail pelvis leg second leg body arm and a squashed head so two lying together there's a bicycle for scale you can see how big these are you Tyrannis is perhaps 7 8 meters from snout to the tip of the tail maybe a Ton Ton half you Tyrannis is covered in feathers from the tip of the snout to the tip of the tail to the toes she completely feathered animal it's also much closer to Tyrannosaurus than his D long so we have two different tyrannosaurs with feathers both a small one and a large one and separated in a great deal of evolutionary history this really strongly suggests that feathers a uniform and present across the Tyrannosaurus we may not have found a feather Tyrannosaurus yet but it may only be a matter of time and certainly I'm confident that Tyrannosaurus had at least some feathers on it perhaps not quite a giant chicken but certainly fluffy so let's try and summarize all of this up to the best we can Tyrannosaurus were around for a hundred million years these were around for a long time they were on at least three different continents perhaps as many as five and therefore it wouldn't surprise me if they eventually turned up in Africa as well and we've got all of the major continents represented for tyrannosaurs there's around 30 species known there are still more coming there's a new Tyrannosaur named only about four weeks ago so we're still finding new species we're still identifying new animals and we're still describing them but the ones we do have some are represented by dozens of specimens t-rex around 20 there's also around 20 of tarbosaurus in asia and about the same for Albertosaurus some of the others rather less known but even guanlong is already known from three complete specimens including a juvenile so we actually have a really great knowledge and understanding of these things their variation how they grew and how they changed and indeed they did grow faster large size we've seen adaptations in the feet which means they were probably effective long distance runners on top of the fact that they had big long legs with a long stride length which would make them quick we've seen evidence for both predation and scavenging so let's have no more predator or scavenger they were predators and scavengers they had great eyesight they would have made effective predators they were probably primary early hunting juveniles when they were and they were feathers animals and you put all this together and I think we have a much better and very different understanding of Tyrannosaurus than we did perhaps even three or four years ago and it's an understanding which is probably only going to develop more in the coming years as we find more and more specimens and as I say Tyrannosaurus as a model organism is increasingly driving forward a lot of knowledge and we do know more about this animal than perhaps any other so I'll leave it there if you want to get hold of me or following my material there is me on Twitter and my website contains a lot of this kind of information if you want to look around at some of my papers and my research and I think I'll leave it there thank you very much for your attention [Applause]

Channel: The Royal Institution

Views: 150,474

Rating: 4.8765035 out of 5

Keywords: Ri, Royal Institution, T Rex, dinosaurs, palaeontology, Tyrannosaurs, dino, Tyrannosaurus, Tyrannosaurus Rex, Jurassic park, science of jurassic park, science

Id: f-jD7kQvyPs

Length: 54min 25sec (3265 seconds)

Published: Wed Jul 05 2017

Reddit Comments

[u/knudude]

I love how we are still learning about Tyrannosaurs species still to this day! I find this video fascinating! Thank you, OP!

[u/HungryKoalas]

David Hone recently published a book called the Tyrannosaur chronicles which is basically a very readable, interesting write up of everything you might want to know on T. rex. It includes info on subjects like the arctometatarsals mentioned in this lecture

[u/EnderCreeper121]

TIL Tyrannosaurs eat Hadrosaurs like Oreos.

[u/Illiterate_Scholar]

Also, you left out the Q&A video. Dave answered questions after the talk.

https://www.youtube.com/watch?v=eTWG5WY_XoM