After the news story a few weeks ago about the replacement Dippy the Diplodocus at the Natural History in London with a blue whale skeleton, there has been a lot of talk in the media and palaeontology community. I’m not going to go into why Dippy should or shouldn’t be replaced, as it has been covered by numerous palaeontologists and news sites (for example, palaeontologist Steve Brusatte and HuffPost Technical Editor Michael Randle argue it’s a good thing, while others like palaeontologist Mike Taylor disagree with the idea), but I will talk about another thing that has come up since then. One thing that a lot of non-palaeontologists have been saying is “oh well it was fake anyways” since it was made up of replica bones rather than real fossils. This is something that really bugs me.
I’m not sure why this has been picked up so much recently that casts and replicas are just “fake”. First of all, fake is something that is made with the intent to deceive. Fake money is meant to replace real money, or fake designer purses are meant to look like the real ones they imitate so people don’t know you have a fake. A replica or cast of a fossil is not meant to deceive. That is not the purpose. Any signs about the specimen will (or at least should) state whether the specimen is a skeleton, cast, or composite. No one is trying to trick you! You just have to read the signs!
The next important point is how these casts are made. Fossil casts are made from real fossils. There are many ways of making them, and I’m no expert so I won’t discuss that here. What I know is that people who make fossil casts, especially good ones, is that they put A LOT of effort into making them look as accurate and real as possible. They are most often made from some kind of mould that is made from the fossil using something like silicone or rubber. After that, plaster or something else hard is poured into the mould which allows for the exact structure of the original to be seen. Finally, the cast is painted and coloured in a way that matches the original specimen. When done properly and well, these casts look almost identical to the original fossil and only close examination by experts will reveal it as a cast. The best cast I have seen was of the pterosaur “Dawndraco” (or Pteranodonif you prefer) in the American Museum of Natural History (AMNH) pterosaur exhibit that ended in January. Just 2 weeks before I had seen the original at the University of Alberta, and was so convinced by the cast that I actually emailed the people who made it to confirm that it was indeed a cast (it wasn’t labeled as a cast, naughty AMNH!). Only because I knew it was not original was I able to spot the signs, but it was hard. The important thing to note here is that they are not just “fake” fossils that are made from someone’s head. These are (usually) skilled professionals who are basing their model off of a real fossil, and it is meant to look as close as possible to the original.
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| Original specimen of “Dawndraco kanzai“, a pteranodontid from Kansas. Original housed at the University of Alberta |
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| Cast of “Dawndraco kanzai” on display in the pterosaur special exhibit at the American Museum of Natural History |
It’s a bit hard to tell from the pictures as the lighting and angle is different, but I can tell you that they looked incredibly similar and the cast looked very real.
The final point to make with this is why museums have casts, especially as their large centre pieces. There are 2 reasons for this. First of all, fossils are rare. Despite what you may think by seeing all these fantastic fossils in museums, they are exceedingly rare. Not every museum has the money to buy a real fossil, or the ability to go out into the field and dig up their own, so they have to rely on casts. If not for casts, very few people would be able to see the specimens. Additionally, if fossils are rare, beautiful, complete fossils that look like Dippy are exceptionally rare. Most often fossils are found with bones missing, or smashed. Fossil replicas and casts allow for these missing bits to be filled in from other partial skeletons, which is what we call a composite skeleton. These can be made from skeletons that are incomplete so some bones are real, some are not. And of course, when we do find one of those exceptionally rare complete or near-complete fossils, casts allow us to share them with the world and show other people. And finally, fossils are of course extremely fragile. It can be very difficult to mount a skeleton in a way that isn’t going to damage the specimen, especially if they are fragile. For this reason, museums will sometimes put the cast on display, and keep the original specimen in the collections in order to preserve it. Does it make it any less amazing? Personally, I don’t think so. I’d rather know that the original is being conserved and properly looked after than see it on display in a museum.
Fossil casts are not “just a fake”. They are replicas of rare and uncommon treasures. Without casts, most of the world would not be able to see these treasures. Dippy, for example, comes from the Morrison Formation of the USA originally. The likelihood of the Natural History Museum in London getting it’s hands on a complete skeleton of a large sauropod from the USA is pretty unlikely. So what would you prefer, no dinosaur at all? Or an exact replica of a real one that existed on another continent, allowing you to wonder in awe?
Musings of a Clumsy Palaeontologist 
I have been making this same point when commenting on Mike Taylor's piece. I get the impression that the 'just a fake' line was one that was consciously dreamt up as part of the NHM's media campaign to justify the removal of Diplodocus from the hall – and they really, REALLY should've know better.
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Yes, I agree strongly too. I think things are a bit more insidious – at least, in so far as they relate to the NHM Diplodocus. That is, the term 'fake' was thrown around as a deliberate means of denigrating the value of the specimen. Shame on those who used it and didn't take time to correct it.
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Using it as a term for the NHM Diplodocus is bad enough, but it also is just generally denigrating to all museum casts/replicas, of which there are of course many. Once you use it for one specimen, then what is to stop you from using it for all casts? You can use it as a reason to get rid of everything that is a cast at the NHM, which I daresay is plenty. Casts are not of any less value for teaching or showing the public about these amazing animals, and in fact many could argue that they are more valuable as they don't carry the same problems of fragility and value as real fossils.
Thanks for the comments both of you!
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I do understand, though, why people don't like see casts and the original fossil as equivalent. When you're looking at a cast, you're not looking at the remnants of the original, living animal – those aren't the bones that were inside that dinosaur. They don't carry the same history as the original specimen. It's like looking at a reproduction of a piece of art, vs. the original painting, for example. But you're right that it's not a matter of 'fake' vs. 'real' with casts, and I think that's where museums perhaps do themselves a bit of a disservice by referring to fossils as 'real', which is why I try to use 'original' fossil vs. cast. I also think museums could do a better job of discussing why we often display casts rather than the original, like by talking about the risks to fossils on display, or the need to have them accessible for active research projects. (I'm convinced that many people really don't see museums as active research institutes that generate new knowledge.) And of course, discussing the process for making casts could make people more aware of the time, effort, and craftsmanship involved in creating casts – whenever I've toured people through the prep lab back at the UofA, I try to show off some of the moulds used for making casts, and people are often very interested and had no idea that casts weren't just hand-sculpted out of someone's imagination!
(Also: Clive did a good job on that Pteranodon cast!)
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The irony of the situation is, of course, that if there's one institution in the world for which the NHM Diplodocus should be priceless as part of their history, it's the NHM. And until recently, they treated it as such (see the recent documentary series, and the 2005 centennial). I have difficulty seeing their recent reversal as anything but a fairly cynical form of opportunism. But what is really troubling, is that as soon as the necessity arises, accuracy goes out of the window.
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I completely agree. I understand why people want to see real ones and why they don't like it as much, but I think that people don't understand the reasons for using casts. I agree that it would probably be much better if museums, institutions, and palaeontologists discussed why we use casts, and what the advantage is to using them. I think it's something that I will try to make sure I talk about more in the future, as I've noticed it is an issue.
And yes – Clive did an awesome job on that cast. When I emailed to make sure it was a cast and not the original, I made sure I told him how great it was. Josh kept saying “Are you sure it's a cast?” and I was thinking “I saw it last week… I'm pretty sure it is?!”
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We're onto you pseudoscientists. Christians Against Dinosaurs will not rest until this dinosaur mythology is put to bed. Stop spreading lies.
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The reason why I question if dinosaurs are real is because non of the museums have real bones and if they do it is only a few that you can't even tell what they actually are. I am not doing to say if other creatures like dinosaurs exist or not, but where is the real evidence. I would not be as suspicious if they were fake casts instead of bones, if there were actually pictures of real bones. Peoplen argue against people who question it and never answer the question. So my question is not why they use casts my question is where are the real bones? If there are real bones send me a picture. I looked online and museums and with humans or even other past animals you can usually find both casts and real bones, so where are the dinosaurs real bones? If most of it was their except a few pieces thats not strange, but when their are only like three real bones what evidence is that?
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Therefore the issue is not why they use real bones and that is all everyone has been saying. It doesnt matter why they do it or what they say about it, the whole question is where are the bones? How come we have never seen the real bones anywhere, no in pictures, not in musuem. SO my question is just answer where are they, and show me it, that is all i want to know. I dont care why they do it, I wont too see them so if you know of real bones share a photo.
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Yes okay, I agree with that, but that is not the question of concern. Where are the real bones? That is the question, I could careless if they used fake or real bones in a musuem but where are the real bones? I have not seen one person answer that question, if they exist the bones would not just disappear. Yes they say there are some bones but the bones in the musuem are like three pieces of an animal? That is hardly any evidence, I can understand missing pieces because it happens but where are they? If you can show me I am open to seeing it, but I have not seen it for dinosours, usually it happens with both old found animals and humans they will have fake and real, so where are dinosours real?
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Brittany Ritenour – Museums are full of specimens both on display and in the collections in the back that are real bones. The picture in this blog post shows a real specimen on the top, and the cast of the specimen below. The top picture is a nearly complete Pteranodon skeleton, with almost the entire animal present. Most often in the fossil record we don't get complete skeletons, because the fossilisation process is not perfect. Skeletons get moved around and jumbled, or bones disintegrate or get modified during preservation. This is why we often find only a few specimens. If you want pictures, look through my blog posts. There are many examples of real fossils here. I'm not sure what you mean by “we never see real bones” because there are literally hundreds of thousands of images out there of real fossils.
This website might help: http://extinctmonsters.net/fossil-mount-faqs/
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