What Did a Baby T. rex Look Like?

[AMNH logo unfolds across an extreme close-up of Tyrannosaurus rex’s face.]

[MENACING, HEAVY BREATHING OVER OMINOUS DRONE]

MARK NORELL (Macauley Curator, Division of Paleontology): When people hear the word “Tyrannosaurus rex,” they think, like, big…

[Extreme close-up of T. rex teeth.]

NORELL: …vicious…

[Close up of large T. rex feet stomping by.]

NORELL: …apex predator.

[Animated T. rex with hair-like feathers walks in profile.]

NORELL: But I like to change people’s preconceptions.

[LILTING MUSIC PLAYS]

[A fluffy T. rex hatchling walks towards the viewer and turns its head inquisitively. Text reads “T. rex, the Ultimate Predator.”]

NORELL: Welcome to the family.

[Curator Mark Norell speaks in the Paleontology collection, in front of a T. rex skull]

NORELL: Tyrannosaurs first appear 150 million years or so ago.

[Animated adult T. rex walks.]

NORELL: T. rex was the most advanced, the most specialized and the biggest tyrannosaur of all. As a paleontologist, one of the big hard things to look at has always been growth.

[Norell speaks in the Paleontology collection. Text identifies him as Mark Norell, Curator, T. rex: The Ultimate Predator.]

NORELL: Because baby dinosaurs and young dinosaurs are just so incredibly rare. And largely that has to do with their bones are extraordinarily fragile.

[Various shots of the tiny bones of hatchling and juvenile dinosaur fossils.]

NORELL: So, it’s only been in the recent maybe 20 years when more and more juvenile and baby dinosaurs have sort of been found. Which we’re getting a window into what the early life histories of these animals was.

[Side angle view of Norell speaking in the Paleontology collection.]

NORELL: Whenever, like, we work on any fossil group…

[Camera pans across life-sized T. rex model in progress. An artist works on a ladder, shaping the animal.]

NORELL: …and we’re making models and that kind of thing, there is a good deal of speculation.

[An artist airbrush paints the mouth of the adult T. rex model, while referencing a photo of a crocodile’s open mouth. Other reference images of birds and reptiles are seen in the modelers’ workshop.]

NORELL: But it’s informed speculation from looking at closely related animals.

[Three artists sit in their studio space. Text labels them as the “T. rex Model-Making Team.” Jason Brougham on the left side of the screen, is identified as “Senior Principal Preparator.”]

JASON BROUGHAM (Senior Principal Preparator, Exhibitions Department): I think this is the first time we’ve ever made the same species of dinosaur at three different stages of its growth and development.

[Woman sculpts mouth of adult T. rex in clay. She is identified in text as “Rebecca Meah, Senior Principal Preparator.”]

REBECCA MEAH (Senior Principal Preparator, Exhibitions Department): I’m assigned to make the adult T. rex.

[Artists sit in their studio workspace, with models in progress behind them. On the right, Hannah Rawe is identified as “Senior Principal Preparator.”]

HANNAH RAWE (Senior Principal Preparator, Exhibitions Department): I was assigned first to make the hatchlings. And then Jason and I decided to switch…

[Rawe examines her model of juvenile T. rex head on a workbench.]

RAWE: …because I was more interested in making the four-year-old T. rex.

[Brougham adjusts fluffy covering on hatchling model.]

BROUGHAM: And I wanted to do the babies. In our show, we’re going to have the hatchling be very densely fluffy, sort of like down feathers.

[Artists’ reference images of modern animals and dinosaur poses are pinned on the wall in their studio. Camera moves in on one image that comes to life with footage of baby ostriches.]

BROUGHAM: Sort of like what you see on a baby ostrich or a baby emu.

[Norell speaks in the Paleontology collection.]

NORELL: From all the inferential evidence we have, these animals would have hatched out of an egg…

[Time lapse footage of kiwi chick hatching out of egg.]

NORELL: …just the way a modern chick does.

[Animated close-up of T. rex hatchling’s face as it blinks and looks around. It has large eyes, tiny, needle-like teeth, and filamentous feathers all over its body.]

NORELL: They would have been covered with a fluffy covering. It just would have looked like a really weird looking big bird when it came out of the egg.

[Norell speaks in the Paleontology collection.]

NORELL: We don’t really have any direct evidence for parental care in Tyrannosaurus rex.

[Reference images scattered on desk. One by one, they come to life with moving footage. First, an emu stands up, revealing a clutch of bright blue eggs.]

NORELL: However, we do have some indirect evidence.

[An ostrich sits near its large eggs in the sand. An adult cassowary guards a group of young birds.]

NORELL: Most living birds, including, you know, primitive birds like ostriches and emus and cassowaries, they have some level of parental care, whether it’s nest guarding or bringing food to their young.

[A crocodile slides from the bank into the water. Its babies sun themselves in the background.]

NORELL: Similarly, crocodiles guard their nests.

[Norell speaks in the Paleontology collection.]

NORELL: So, at least at the nest guarding level, we would predict, then, that tyrannosaurs would have the same kind of thing.

[A fluffy T. rex hatchling looks inquisitively at the viewer, then looks up, revealing small, needle-like teeth.]

NORELL: When a little tyrannosaur was born, the teeth were a lot different than the adults.

[A Komodo dragon opens its mouth on a beach.]

NORELL: In lots of living animals, especially big reptiles like Komodo dragons…

[A young Komodo dragon sits amid leaves on a high tree branch.]

NORELL: …they also go through an ecological shift of what they eat from the time that they’re hatchlings and juveniles…

[Amid a group of reference images pinned to the wall, one comes to life, showing an adult Komodo dragon pacing along a beach.]

NORELL: …to full adulthood. They have different diets.

[Close-up of juvenile Komodo dragon.]

NORELL: So, the smallest ones feed on insects and small reptiles.

[Group of adult Komodo dragons eats the carcass of a large hoofed mammal.]

NORELL: But then when they’re adults they can even take down large animals, like animals that weigh almost as much as they do.

[Norell speaks in the Paleontology collection.]

NORELL: As adults, the primary way in which the big tyrannosaurs hunted…

[Close-up of T. rex mouth and large, pointed teeth.]

NORELL: …is that they have these really deeply rooted, very stout teeth.

[3D model of T. rex skull, with musculature indicated. Mouth is first open and then snaps closed.]

NORELL: So, they were able to bite into things with such force…

[Norell speaks in Paleontology collection.]

NORELL: …that it wasn’t like a lion or a leopard. They would actually cause the thing to explode because they’re able to bite so hard, and their teeth could just go through bone. They could crush everything.

[Close up of model T. rex juvenile teeth.]

RAWE: You know, you think of the teeth as being crescent moon-shaped…

[Close up of artist gluing teeth onto juvenile T. rex face.]

RAWE: …but in fact, it’s not as much of a curve.

[Rawe fits teeth onto juvenile T. rex. Reference image shows T. rex with closed mouth and teeth jutting out in an overbite.]

RAWE: I decided to sculpt the four-year-old T. rex with his mouth closed.

[T. rex artists speak in their workshop.]

RAWE: Because I just kind of thought it was maybe more interesting as a study of nature…

[Rawe sculpts juvenile T. rex model.]

RAWE: …that, you know, the majority of the T. rex’s time spent alive, I’m sure, was with their mouth closed. And I’m actually working off of a really new discovery, and very little fossil evidence.

[Animated adult T. rex walks. Camera cuts to close-up shot of arms moving.]

NORELL: There’s been a lot of speculation about what Tyrannosaurus rex used its miniscule arms for when it was an adult.

[Animated hatchling walks in side view. Its long fluffy tail moves with each step, and its arms appear longer to its body size than on the adult.]

NORELL: But when a Tyrannosaurus rex first hatches, the arms would have appeared quite a bit longer than they do in an adult.

[Norell speaks in Paleontology collection.]

NORELL: Basically, the body grows faster than the arms do. So, it’s not like the arms diminish in size.

[Close-up of arm on adult T. rex model in-progress, then wider shot showing how tiny the arm is, relative to the full body size.]

NORELL: They just don’t grow as fast as the rest of the body does.

[Artists speak in their workspace.]

RAWE: One of the main things I think that we sort of used each other’s reference points on were the hands and feet.

[Reference images of emu and ostrich feet are taped to a work table.]

MEAH: We copied an emu-slash-ostrich.

[Model T. rex foot sculpted in clay.]

MEAH: If you look at, like, the footprint left by a T. rex…

[Close-up of emu’s foot. Shot of emu walking in grass.]

MEAH: …it looks almost identical to an emu footprint. So-

[Artists speak in their workspace.]

BROUGHAM: But much bigger.

MEAH: But much bigger, yeah.

[Illustration of juvenile T. rex, its body covered in striped patterns of feathers.]

NORELL: When the animal was young, it was a really kind of, like, gangly animal.

[Norell speaks in Paleontology collection.]

NORELL: And it would have had a much more cursorial gait, meaning it was a fast runner. As opposed to the adult…

[Tiger hides in bushes, moving only its ear.]

NORELL: …which was probably just a stealth predator. I mean, that’s the way tigers, for instance, hunt today and stuff.

[Norell speaks in Paleontology collection.]

NORELL: Is that they’re not like cheetahs. They don’t go running forever and run stuff down.

[Pinned to the artists’ worshop wall are a sequence of images showing a tiger chasing down and catching a wild boar.]

NORELL: They hide in the bushes and they’re ambush predators.

[Extreme close-up of adult T. rex face and skin.]

NORELL: A lot of people really wonder what the skin of Tyrannosaurus rex looked like.

[A large Komodo dragon walks along a trail.]

[LIGHT, BOUNCING MARIMBA MUSIC]

NORELL: And a lot of them equate the skin of a tyrannosaur to be just like the skin of a lizard or a snake.

[Norell speaks in Paleontology collection.]

NORELL: And they were scaled, but scaled in a very different kind of way.

[Close-up of a tortoise, chewing on grass.]

NORELL: The skin would be more like a leathery covering—what the leg of a turtle looks like…

[Pinned to the artists’ wall, a close-up of chicken feet comes to life, as the chickens scratch in the dirt.]

NORELL: …or even the foot of a chicken.

[Norell speaks in Paleontology collection.]

NORELL: Also, you know, we feel that even adult tyrannosaurs were feathered.

[Illustration of Yutyrannus, a tyrannosaur with large teeth and claws, but completely covered in feathers and sporting a fluffy tail.]

NORELL: There’s an animal from China called Yutyrannus…

[Images of Yutyrannus fossils, showing tyrannosaur-looking skull, and tail with feathery streaks evident surrounding the vertebrae.]

NORELL: …which is a fairly close relative to Tyrannosaurus rex, and spectacular fossils of it show that the animal’s completely covered with feathers.

[Artists speak in their workspace.]

BROUGHAM: When we don’t have specimens that preserve the skin texture, we have to sort of infer what it could be.

[Brougham sculpts hatchling model. Meah adjusts clay model of adult T. rex head. Rawe glues eye in juvenile T. rex model.]

BROUGHAM: For each model, there’s a few choices that you have and you run them past the curator and see if they think they’re plausible.

MEAH: I think where we like to do our best work…

[Artists speak in their workspace.]

MEAH: …is making it convincing to the audience.

[Norell speaks in Paleontology collection.]

NORELL: Since its discovery, Tyrannosaurus rex has been…

[Time lapse footage of T. rex fossil skeleton being assembled in exhibition space.] 

NORELL: …the most iconic, the biggest, the meanest, probably by far the best-known dinosaur. And you know, we want to give people a very different look and appreciation for what a remarkable animal Tyrannosaurus rex was… 

[Animated adult T. rex lopes into frame.]

[LARGE SNORTS AND SNIFFS] 

NORELL: …and the evolutionary steps that its ancestors went through to get there.

[Animated T. rex notices viewer, and chomps down, its mouth engulfing the screen.] 

[Credits roll.]