Gastroliths

A couple of years ago I was working on an exhibit about jaws and teeth, in collaboration with my colleague Randy Mooi. One of the key purposes of this exhibit was to demonstrate how different kinds of vertebrates process their food. We were exhibiting a lot of different kinds of skulls and teeth, so the space for explanatory text was limited, and we had to try to find creative ways to get the information across to museum visitors. Since some animals are very familiar to us, it is relatively easy to explain eating in many mammals and birds, but other less familiar animals turned out to be quite tricky.

One of our exhibit cases explained dinosaur teeth and jaws. Many dinosaurs apparently swallowed pebbles or cobbles that assisted with grinding their food; the stones were held in a muscular gizzard. We have examples of dinosaur gizzard stones (or gastroliths) in our collection, which were found associated with dinosaur skeletons in the western United States. They are interesting objects, but if they are put in an exhibit case without much explanation, they will just look like a “bunch of rocks.”

Modern birds also have gizzards, and people who keep birds such as budgies or chickens know that they need to be provided with gravel if they are to remain healthy. We thought we would have fun with this comparison, so we bought some budgie gravel and played with what the packaging would be like if people had to buy stones for their pet dinosaurs:

Bird gravel and dino stones (note that I was probably incorrect to list some of these groups of dinosaurs, as only some kinds are known to have had gastroliths)

We were very pleased with this, and we put a fake “dino stones” box in the display case beside a genuine bird gravel box (to fit it in the space, they were unfortunately the same size). In hindsight, though, I suspect that the fake was too subtle to make the intended point. There was no explanation of the boxes and we never received comments about them from anyone who saw the exhibit. I hope no one thought that Dino Stones were an actual product …