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The Anatomy of Smaug
By ArchedCory

I have always loved dragons, so of course I always loved Smaug. And I was so excited when I first heard that I will eventually see him on screen! After my earlier essay The Evolution of Smaug which only covered book-Smaug and the way he changed during the writing process of the book, I simply couldn’t wait to delve into the anatomy of film-Smaug. After seeing “Desolation of Smaug” a couple of times now I finally feel like I am capable of describing his body a bit. As always, if you have anything to add, please do so in the comments!


Skin texture:

As it should be the skin is thinner on the wings and face and thicker on the body. We see a close-up on the scales on the chest. They are extremely thick, even on a reptile that size. Usually the scales in reptiles put together make the illusion of a smooth skin (think of snakes and lizards).


Bobtail Lizard (Tiliqua rugosa)

His scales however remind me of the Bobtail Lizard (Tiliqua rugosa), a skink species endemic to Australia. Their skin looks more like a pine cone than a smooth surface. And in fact “closed pine cone” was the first image I had in my mind when Smaug’s close-up appeared as well. Crocodiles also have scales of the same thickness, but the shape looks quite different.

pine cones

pine cones – closed and open

The skin on his throat is loose and floppy and this seems to be a common feature of rather large reptiles such as Giant Tortoises or Iguanas. On a reptile the size of Smaug that is a nice little detail.



The animation of the skin is perfect. Try to watch when the skin on his “hands” stretches upon grabbing something or putting them down – the colour change and light effects are neatly done.



The nictitating membrane is back. Yes! The movement of its retraction slowed down though and that is exactly how animals react after a long sleep. The second closing of the eye moves the membrane a lot faster. Very lifelike!


Smaug’s nictitating membrane retracts

I have one slight problem with the eyes though. They look terrific, don’t get me wrong. However the pupils are narrowed down quite a bit. Considering we are in a very dark environment AND Smaug just woke up, they should be as large as they get! But no matter if he is inside or outside, fire ahead or darkness, his pupils always are roughly the same size. I wish they would have thought of that! At least the pupils narrow down in the instant he opens the eyes, which they should do when suddenly exposed to a lighter environment.

His pupils do widen when he is aroused though just like ours do when we are under high emotional influence (fear, anger, happiness, doesn’t matter).


When it comes to teeth the animators have obviously studied crocodiles or Komodo dragons (Varanus komodoensis) very closely. Just like Smaug, they are also carnivorous reptiles. As such they have very typical teeth. Unlike mammals with their distinct differentiation in incisors, canines, premolars and molars, teeth in reptile jaws are a lot simpler, and more or less all look the same. They only differ in size, but most of the time they are conically shaped. Back to the crocodiles/Komodo dragons: Their teeth are long and exceptionally sharp, after all they want to score kills with them. And Smaug’s teeth are very close to that concept.


Komodo dragon skull

In the cinema it is pretty much impossible to count the teeth. Maybe with stills of the Bluray/DVD version it could be done. But we have to wait for that.



At first glance Smaug’s head bears a strong resemblance to Tyrannosaurus rex. Apart from the fact we only know skulls of T.rex and not the detailed shape of muscles and skin covering it up, there are still differences that can be noticed: The ratio between length and height seems to be slightly different, with Smaug’s head being longer and narrower. The nostrils are a bit further back and the teeth are shorter and sharper


Tyrannosaurus rex skull

With his rather long snout, sharp teeth and floppy throat he could also be in a way compared to crocodiles. Considering T.rex and crocodiles have quite a different internal anatomy (dinosaurs and crocodiles systematically speaking are not closely related) it would be interesting to see Smaug’s skull. We do know that Weta likes to build their CGI characters layer by layer from skeleton up, so I hope at one point in the future they will give us Smaug’s skull!


Crocodile head

Smaug is capable of many facial expressions which is particularly interesting for a reptile. They are especially known for their stiff emotionless faces, so giving Smaug credibly human movements which convey emotions such as greed, anger, surprise, or happiness is an interesting approach. It’s not reptile-like at all and something we owe to the simple fact that he is a fantasy creature.

Number of limbs:

Perhaps you are familiar with my essay on The Hobbit’s biology written after watching part 1 of the trilogy. We only knew Smaug’s legs, eye and tail at that point and I claimed to be able to say with complete surety that Smaug walks on four legs and therefore must have extra wings to add up to six limbs.

Well, tough luck, everybody can see in “Desolation of Smaug” that he has four limbs like every proper vertebrate, with his wings being at the same time front legs as well. So does this mean I was wrong?

No, in fact the film team even gave me a proof that I WAS right!

Smaug’s feet in the theatrical version – which are clearly showing the motion of a regular quadrupedal walk – were actually changed into the distinct front claws of his wings in the Special Extended Edition! Which means the Smaug you saw in the cinemas in “An Unexpected Journey” is anatomically not the same Smaug you saw in “Desolation of Smaug” a year later!


From the Theatrical Edition


From the Extended Edition

However even in the changed version there is still a mistake: The paw that reaches inside Erebor’s front door to break it down is still the old front leg of quadrupedal Smaug.


Smaug breaking down the door from the Extended Edition

Hind limbs:

They seem to be proper reptile feet with five toes and claws. However when you look closely you’ll make out a thumb. While that is almost unknown in reptiles it is especially in hind limbs. (Yes, I wrote “almost”, I am aware of chameleons). Opposable digits are mainly there for grabbing, in hind feet mostly for climbing. So what could possibly be large enough for Smaug to climb? Further, he is perfectly capable of grabbing things with his front claws (as seen multiple times in the film), so why would he use his hind feet? Is he going to grab objects with his hind legs while flying? (Perhaps those juicy maidens he likes to feed on.) We will probably never see it, but it’s an interesting detail to consider nevertheless.


Concept art of Smaug’s hind leg. The thumb is on the left. It is much more visible in motion in the film!

Front limbs:

And now we finally come to Smaug’s wings everybody has been speculating about for such a long time. To explain them I first have to make a digression towards real world wings. In vertebrates wings have evolved three times independently and, interestingly enough, Smaug’s wings bear characteristics of all three. One thing we have to consider: Wings always need to have a large surface and be stable enough to stretch and carry the body’s weight without ripping.
So let’s look at these three versions of real world vertebrate wings:

-) Birds


Birds achieve their flying ability by special flight feathers that enlarge the surface of their wings enormously. Additionally they have similar feathers on their tail and spreading the tail provides even more surface. Notice that the feathers grow on the arm and more or less one remaining (but very short) finger and there is no connection whatsoever to body or hind legs.

-) Bats


Bats basically fly with their palms. They don’t have feathers, so they need to create a large wing surface by vast amounts of skin. However the skin needs to be spread to support the body weight, so it reaches from tail to hind leg and all the way to the hand. To increase the surface area four fingers are elongated to spread skin between them. Only the thumb is short and pretty much useless. Bats are very clumsy when they try to walk or climb which explains why you will hardly ever see them do so. The single remaining claw of the thumb is hardly enough to find a decent grip.

-) Pterodactyls


Pterodactyls were the only reptiles in history ever capable of active flight. Their wings are similar to those of bats with a slight difference: They only have one elongated finger. The wings were spread between that one finger, body and legs. The tail might have been involved. The other three fingers are short and are used as a hand. Pterodactyls were most likely a lot more elegant than bats when walking or climbing on all four limbs.
What about the fifth finger? Well, they only had four, but that was obviously enough for a working wing.

So where are Smaug’s similarities to these three? With birds he shares the fact that his wings are not attached to body, hind legs or tail. With pterodactyls he shares the remaining front claws next to the wing, and with bats the fact that more than one finger is used in the spreading of the wing. Which means he is a collection of characteristics that have all appeared in real world animals but were never combined into one animal. In that matter he reminds me of oliphaunts. They also have little details from different extinct elephant species gathered together to a collection that never existed but could still be possible. (Well, apart from the size…)


Early, abandoned concept art of Smaug’s wings fashioned after bat wings. This concept can actually be seen in one shot in the film: when Smaug briefly flies over Dale. Of this abandoned concept only one detail made it into the final version – the elbow spur!

But let’s look at Smaug’s wings in detail now. Apparently considering “An Unexpected Journey” theatrical version and concept art in the Weta book they have tried different versions of his wings. At one point he had two wings additional to four legs, at another they even tried to design his wings exactly like those of bats.


Smaug flying from the Extended Edition. You can see the abandoned bat wings here, they already look different in Desolation of Smaug!

The final concept however looks like this:

Concept art of Smaug’s front leg

Smaug uses three of his fingers (thumb, index and middle finger) as hands and claws. Those are the short fingers you see when he grabs and climbs. The other three fingers (ring finger, pinky and well, one more) are elongated to spread the wing. Yes, you read right, Smaug has SIX fingers. Is that even possible?

Well, back when fish grew limbs and fingers they tried a lot of different numbers of fingers and toes, while limbs were always restricted to four. Ancient amphibians (Ichthyostega and Acanthostega) could have anything between five and eight fingers. Only when amphibians modernized, and definitely by the time they evolved into reptiles, the number five was locked into the genetic pool. That ancient gene of polydactyly (= “too many fingers”) is still slumbering in every tetrapod. There are very rare exceptions such as some dog breeds and especially moles which have six fingers as a normal condition. In every other vertebrate six fingers are a genetic mistake. Which means strictly genetically speaking Smaug is a mutant!

I only found one scene with closed wings where the three long fingers are clearly visible. In the flight scene at the end however you can see his wings perfectly spread between four spines. Three are his fingers, the fourth one is a spur growing out of his elbow.


The largest flying animal in all of history was a pterodactyl. Certain species of the genus Quetzalcoatlus reached a wingspan of 12 meters, which is almost double the size of the largest flying bird in history and four times the size of the largest current flying animal – both the Wandering Albatross and the Andean Condor hold that record with wingspans of over 3 meters. We can assume Quetzalcoatlus pretty much reached the limit of body size that is still able to fly. He had something in common even with large currently living birds: The larger the wingspan, the less acrobatic the flight technique is. Condors and other vultures for example mostly glide in the air with hardly ever flapping their wings. It is most convenient considering the weight these wings have to carry. It is the same reason why you won’t ever see vultures, swans, large eagles or the like fly narrow curves, flap their wings rapidly or start and land abruptly. Those large birds usually even need a really long start and landing lane, similar to those of airplanes!

Flying animals in the real world also apply certain tricks to keep their body weight down. Bats and pterodactyls have really slim and light bodies, birds have air filled chambers inside their body and both the bones of birds and pterodactyls are hollow.

So what about Smaug? He exceeds the largest possible size for flight multiple times. Even though he is a rather slim dragon compared to those in other films he is still way too heavy to lift off the ground. This means his wings would probably rip apart the moment he tried to fly, what helps even less is the fact that there is nothing on the body side to stabilize them. At least the motion is applied correctly: He flaps quite a lot when he starts but then also goes over into gliding quite soon.

Bottom line: an animal the size of Smaug could simply never fly, but then again he wouldn’t exist at all, couldn’t talk or breathe fire, so this problem could be neglected. After all he is a dragon – a fantasy creature – some things about him just have to be impossible and that is good. In exchange his other characteristics are incredibly well thought out!


At least in this shape he definitely can fly!