I had the privilege of being taken in as an explainer for this exhibit during the spring and summer of this year before I had to move out of New York. When I first stepped in for the training walkthrough, the amount of sheer information was almost overwhelming, even for a museum. Essentially this exhibit has a two main messages. The first is to explain, on a broader sense, by using dinosaurs as the model, how evolution works. The second is to bring home the fact that birds are dinosaurs, by the use of many awesome physical pieces of evidence, some of which have never been on public display before.
|One of the life-sze Microraptor models hanging from the ceiling. They have been painted glossy black-blue in accordance with the preserved melanosomes in their fossilized feathers.|
When you first walk in you are greeted by life-sized life reconstructions of several of the keynote dinosaurs featured in the exhibit. Most important is probably Citipati, due to the sheer amount of fossil material that has been found, and the fact that the American Museum of Natural History does a lot of field work in Mongolia, where this dinosaur was native to, and therefore has access to a lot of its fossils. The largest and most dramatic model, however, is definitely Yutyrannus. To my knowledge, a life-sized life reconstruction of this monster has never been made before this, and it looks great. Many of the life reconstructions actually feature real bird feathers, as well.
|My first interaction with the Yutyrannus was a bit rocky. We're cool now, though.|
One key connection between birds and other dinosaurs is the act of nest building. This exhibit features several spectacular fossils of nests and eggs that were laid by dinosaurs millions of years ago. The manner in which these eggs were laid actually gives us clues as to just how closely related a species dinosaur mother was to her modern relatives.
|Life-size replica of a Gigantoraptor nest on display in Dinosaurs Among Us. Yes, you're allowed to stand in it.|
This, laid by a troodontid, called Byronosaurus. The eggs aren't arranged in pairs. This looks more similar to a clutch of eggs laid by a modern bird. This is because modern birds only have one functional ovary, and therefore only lay one egg at a time, resulting in this arrangement. (Fun fact: They have two ovaries as an embryo, but lose one as they develop. This tells us that they evolved from dinosaur ancestors with two.) We used to think this was an adaptation for lightness so they could fly...but here are some non-avian dinosaurs that didn't fly...and went extinct that way.
Telling you just how close a particular non-avian dinosaur is related to modern birds is a constant theme throughout this exhibit. In fact, under each specimen, there is a tiny infograph, modeled after a barometer, with the needle pointing somewhere between the earliest ancestral dinosaur and modern birds.
|Dino-Bird-o-meters are all over this exhibit. In this case, it is telling us that Yutyrannus, a tyrannosauroid, is more closely related to modern birds than it is to many other kinds of dinosaurs.|
After eggs and nests the exhibit looks at the actual anatomy of different dinosaurs, especially the bones. As with single ovaries, hollow bones was another feature we used to think birds evolved specifically for flight. Since then we have learned that this was also not the case. Large dinosaurs, like Allosaurus, demonstrated here, and even gigantic sauropods, had hollow bones. We now think this was a sign of having a more efficient one-way respiratory system that birds retain today. When a bird breathes air into its lungs, it doesn't simply get exhaled out the same way it went in. It goes into more chambers throughout the body, including ones connected to hollow cavities in the bones. Birds today use it to help them fly better, most likely, but prehistoric dinosaurs probably used it for other reasons, like getting oxygen throughout their huge bodies more efficiently. We have also found similar respiratory systems in modern crocodilians and even some kinds of lizards so...yea definitely not a specific flight adaptation.
|This is a broken piece of an Allosaurus leg bone,displayed next to the bone of a modern bird. The hollow inside has since been fossilized with a different mineral from the actual bone.|
Having fused clavicles, or a wishbone, was another feature previously thought to be exclusive to birds...until it started popping up in the fossil record in dinosaurs like Velociraptor. This exhibit has an awesome articulated Velociraptor specimen on display with the wishbone clearly visible.
|Beautifully articulated Velociraptor specimen. You can see the shallow v-shaped clavicle at the base of the neck.|
My favorite specimen in this exhibit would be the Tyrannosaurus wishbone, however. That's right, T. rex had a wishbone, just like that turkey you ate. To drive the point home even harder, it is displayed in a case surrounded by the wishbones of various modern birds.
|T. rex wishbone. My favorite piece in the exhibit.|
Finally the exhibit goes from internal anatomy, like bones, to external anatomy, like skin and feathers. A myriad of specimens showcasing visible preserved feathers on fossilized bodies is showcased here from the curious quill-like structures of Tianyulong...
|Tianyulong cast on display, complete with bristles on the back.|
To the extremely feathered, Confuciusornis, in all its plumed glory.
|Confuciusornis. Just one of many feathered specimens on display at Dinosaurs Among Us.|
At the end of this exhibit, a common question we receive from guests is "So what defines a bird?" This is a great question. Yes, birds are dinosuars...but not all dinosaurs were necessarily birds, of course. It's like saying a Ferrari is a car, but the car I drove to New Jersey to see my family today sure as heck wasn't one! So what they are really asking is where in the fossil record do we draw the line between birds and non-avian dinosaurs? What combination of features can we confidently say that all birds must have to be considered a bird?
The answer to this is as frustrating as it is beautiful; We don't know! And to put it bluntly...we shouldn't really care. Nature has nothing to do with which label we put on which organism. They evolve to survive and the process just is what it is. Labeling something a bird based on an anatomical milestone just can't flow with what actually happens. The amazing side of this seemingly frustrating coin is that this means that the fossil record for non-avian dinosaurs to birds is rich with plenty of specimens to learn from for years to come. This is in harsh contrast to as little as a few decades ago when all we had to work with as far as feathered, birdlike dinosaurs were concerned, was good old Archaeopteryx, once considered "the first bird" and now just one of many feathered, birdlike dinosaurs.
If you have an interest in paleontology, birds, or nature in general PLEASE visit this exhibit if you have not already. The American Museum of Natural History has been a prominent part of my life since I was born. I've seen lots of fantastic temporary exhibits come and go. That being said, this exhibit blew me away. I purposely didn't write about and include photos of everything in there. In fact, I only showed you a smaller portion of what this exhibit has to offer to further encourage you to go out and see it in person for yourself.