Are Dinosaur Bones in Museums Real?

One of the most famous Tyrannosaurus rex skeletons, “Stan” the T. rex, may also be the most well-traveled T. rex. At the moment, he currently resides in Texas, New Mexico, Washington, D.C., Kansas, Wyoming, Indiana, Wisconsin, the United Kingdom, and even Tokyo, Japan.

There’s only one Stan, so how can he be in so many places at once? The answer is simple: people made and distributed replicas of his skeleton.

You might wonder: are dinosaur bones in museums real fossils? While some displays use real fossils, many bones on display are replicas. Scientists may make replicas of fossils from dinosaurs and other animals for several reasons.

First, fossils are often rare and valuable, so museums may need to purchase replicas instead of original fossils to add them to their collections. Second, replicas of fossils make it easier for scientists worldwide to research particular samples. Lastly, replicas may be made simply for practical purposes.

The Case for Composite Skeletons

In the case of Stan, for example, his skull proved too heavy to display on his skeleton. Thus, his skull was displayed close to the ground and his skeleton had a much lighter replica attached to it.

Even when a dinosaur skeleton is real, however, it often has replicas and/or real bones from other skeletons of the same species added to it. Dinosaur skeletons usually have these additions because dinosaur skeletons are rarely ever found complete.

Consider Sue, a T. rex on display at the Field Museum in Chicago, Illinois: although she is the most complete T. rex yet discovered, only 90% of her skeleton by volume and 250 of her approximately 380 total bones were discovered.

That means that approximately 130 bones had to be added to her skeleton to account for all the gaps! See the image, below.

Scientists call skeletons such as Sue composites because they include material from multiple skeletons. Indeed, almost all dinosaurs on display in museums are composites. Finding a 100% complete dinosaur skeleton is extremely rare.

The above image highlights Sue’s real bones in bright green, while replicas of bones from other T. rex skeletons remain dark and unhighlighted. Note that I could not confirm whether any of the bones from the other animals were real.

Her skull isn’t highlighted; that means that it, too, is a replica. Just like Stan, her skull was too heavy to mount up in the air, so it’s located in a display case nearby.

If you want to learn more about Sue, you can read about this dinosaur on the Field Museum’s blog. Be sure to check out her recent makeover too.

Fossil Reconstructions

In some instances, a skeleton may be found that is so rare that no other skeletons of that species have yet been discovered. Or perhaps multiple specimens have been found that are all missing the same bones. When these situations occur, scientists must either choose to leave any gaps in the skeleton blank, or they may instead make their best estimate as to what the missing parts looked like and try to reconstruct them.

As their understanding of the species continues to improve, their models will grow better and better until they, hopefully, resemble what the animal looked like in life. If the fossils in question are one-of-a-kind or too large, heavy, or fragile to transport, they are less likely to become mounted.

Indeed, this process of figuring the skeleton out occurs with every dinosaur species discovered, because so many skeletons are missing bones. This gradual advancement of paleontology relies on procuring new quality specimens. We have an in-depth article that explains why paleontology is so important.

Consider Parasaurolophus walkeri. The above image shows the first discovered skeleton, known as the holotype, of P. walkeri. Notice that it lacks two legs and most of its tail.

When this fossil was discovered, its discoverers likely could only guess what the rest of the animal looked like. As more fossils of this species have since been recovered, scientists have been able to come up with much more complete reconstructions of this animal.

Take a look at the sample on display at the Field Museum in Chicago shown below. How do these two skeletons compare?

How to Determine If Dinosaur Bones Are Real or Casts

Now that you know why casts are important, you may have one more question: how do you tell the difference?

To determine if a fossil display is real or a cast, you can consider several factors:

1. Appearance and Texture: Real fossils typically have a more varied texture and coloration. They might show fine details like bone texture or fossilized skin impressions. Casts, on the other hand, often have a more uniform appearance and may lack intricate details.
2. Weight and Temperature: Real fossils are generally heavier and colder to the touch due to their mineral composition. Casts, made from various materials like resin or plaster, tend to be lighter and not as cool to the touch.
3. Display Context and Labels: Museums and exhibitions often label their displays. If a fossil is a cast, the label usually indicates this. Pay attention to any provided information about the origin and discovery of the fossil.
4. Seams and Joints: Casts often have seams where the mold parts join together. These seams are not present in real fossils. Examine the fossil carefully for any lines or marks that suggest it was made in a mold.
5. Consistency with Other Displays: Compare the suspected fossil with other fossils in the same exhibit. Differences in texture, color, and detail can be clues. Real fossils often show signs of wear, breakage, or repair that casts might not have.
6. Ask an Expert: If you’re still unsure, ask a museum staff member or a paleontologist. They can provide insights into how the fossil was prepared and whether it is real or a replica.
7. Presence of Matrix: Real fossils are often found in some form of matrix (the rock or sediment in which they were found). If the fossil is completely free of any matrix or the matrix looks very uniform, it could be a sign of a cast.
8. Reflection and Shine: Casts might have a slight shine due to the materials used, while real fossils generally have a more matte finish unless they have been treated for preservation.

Casts resemble actual fossils in every way, but a keen eye can spot the difference. Next time you’re in a museum, see if you can tell the difference.

Are Dinosaur Bones in Museums Real?

Many of the fossils on display in museums worldwide are real, but many are compiled from replicas of original fossils. Scientists make these fossil replicas because the original fossils are often rare, valuable, fragile, difficult to transport, and/or scientifically valuable.

Given this fact, replicas make fossils more accessible to both the public and scientists for outreach, display, and research purposes. The missing bones may not even exist, and therefore, are created from our knowledge of similar animals.

So when you see a dinosaur on display, remember that while not all bones are authentic, they represent the most accurate display possible given the reality of fossil display.

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