Is it real? – models, casts and replicas

One of the most common questions asked about our specimens, from visitors of all ages, is ‘Is it real?’. This seemingly simple question is actually many questions in one and hides a complexity of answers. 

In this FAQ mini-series we’ll unpack the ‘Is it real?’ conundrum by looking at different types of natural history specimens in turn. We’ll ask ‘Is it a real animal?’, ‘Is it real biological remains?’, ‘Is it a model?’ and many more reality-check questions. Here’s your final installment…

There’s nothing like standing under a huge T.rex skeleton, staring up at its ferocious jaws, to get the blood pumping. Visitors often ask “Is it real?” and look rather deflated when they find out it’s a cast. So why do we include casts, models or replicas in our displays, if they don’t have the same impact as the real deal? The truth is that they’re valuable additions to museum displays, allowing the public to engage with specimens that would otherwise be hidden behind the scenes.

On any visit to the Museum, you’ll come across labels that tell you the object you’re looking at is a cast. It could be a dinosaur skeleton, a brightly coloured fish, an amphibian specimen or even the head of the Oxford Dodo. But what is a cast? Casts are made by taking a mould of bones, or sometimes whole animals, then filling that mould with resin, plaster or fibre glass to make a copy. They can be incredibly accurate or lifelike.

It’s extremely rare to find whole dinosaur skeletons, and very difficult to mount heavy fossils (weighing tonnes) onto large armatures. Our Tyrannosaurus rex is a cast of the famous Stan, found in South Dakota, USA, and one of the best preserved skeletons of its kind in the world. But the “real” Stan is kept at the Black Hills Institute of Geological Research, so the only way we can offer the breath-taking experience of standing beneath a T. rex here in Oxford is by using a cast.

Even Stan has some bones missing, so sometimes casts are made up of several individual skeletons. Copies can also be made to give the impression of a more complete skeleton. For example, if a left bone is missing, a mirror of the right hand bone can be created. We call these specimens “composites”.

Animals such as fish and frogs aren’t easy to taxidermy; their skins shrivel, dry out, lose their colour and crack. Painted casts are a good way to show what these animals look like.

Models, such as the giant insects on the upper gallery and the Archaeopteryx in the Evolution of Flight display (at the top of this post), are very clearly not real. These are made by model makers to show something that can’t be seen or shown with real specimens. The giant insects are a way of showing the detail of very small creatures. The palaeontological models show what we think extinct animals might have looked like in life. They’re hypothetical models based on the latest scientific research, which can change very quickly, and always have an element of artistic assumption or speculation in the details.

In this series we’ve talked about taxidermy, skeletons, fossils and more, but these are just a few of the kinds of specimens we have on display. There are also nests, plastinated models, microscope slides and dioramas, which all have a mix of real and non-real elements. When you are looking around the Museum try to think about which specimens are real and which aren’t… and how does that make you think about the specimen?

Read the other posts in the Is it real? series here.