Quadruped Structural & Animation Notes

Well, it's not very often that I have a kernel of wisdom to share, but when it comes to quadrupeds, (four-legged animals) it's my humble belief that I really do know my stuff. While Don does an alright job of teaching quadruped animation, his methods always left a bit of a dry taste in my mouth, particularly as he only skims the surface. Don teaches students quadrupeds in a very basic context, leaving out a lot of important information that I believe would make it easier for people used to drawing bipeds (two-legged animals) to learn how to draw quadrupeds. You can't animate a quadruped unless you understand how it works, just as you can't animate a biped just the same. So here's some basic structural notes for starters:

1. This is very important - animals have the same joints as humans. The only reason they look different is because they are in different places! This is called analogous structure and every animal with a skeleton has it, from birds to deer to wolves and humans.



Click on the images to get a close look at the notes I drew which help explain what I am describing. Photographs of my notes courtesy of my roommate Rachel Stolberg.

Now; the basics of analogous skeletal structure (you learn about analogous joints in highschool biology by the way. Most artists just don't remember it, or don't realize its great usefulness.)

- Our arms form an animal's front or more properly forelegs. Our legs form an animal's back or hindlegs. Limbs are also known as quarters.
- Our hand/toes form a typical predatory quadruped like a dog's paw. Predatory animals include everything from cats to weasels and all have the same basic structure.
- Our wrist is a dog's carpus or fetlock. Keep in mind that animals have a more limited range of movement in this joint than we do and can NOT twist it 180 degrees like we can. The reason for this? Well, think about it - have you ever put your full weight on one of your wrists? It's nigh impossible and in fact, it hurts like hell. This is because our wrists have compromised the strength to take our body weight for the ability to swivol. This is why when people break their fall with one hand they often sprain the wrist or break it. Because animals have only limited swivolling ability in their wrists which are also better muscled than ours, they can take their full body weight without snapping the joint.
-Predatory animals such as dogs are born with dew claws which is their version of our thumb. While you can get away with not animating these on a domestic dog or cat, they are important landmarks on animals like lions, so please do your best not to forget them.



- Our wrist is a typical herbivore like a horse's front 'knee' or 'carpus.' They have even less swivolling ability in this joint than a carnivore like a dog's, as they do not require it to grab prey as a carnivore might.
- The long part of a horse's foreleg below its 'knee' or 'carpus' is the long bone in our hand, called a 'pastern'; the fetlock below this bone in a horse is our knuckle. A horse hoof is a finger; the rest of a horse's residual fingers or toes can be found in x-rays, higher up the leg. Evolution has made these toes unneeded for horses and other hooved animals. Animals such as cows and deer with cloven hooves are exactly the same as a horse, but with two toes instead of one.



- Look at my notes and the provided skeletal images. Animals have almost exactly the same hindquarter joint alignment as us, only their knees are closer to their bodies and our foot is the long lower part of their leg.
- Everyone knows that hitting their heel against the ground barefoot while running is painful - this is because this joint in animals was never meant to touch the ground except at a standstill. This joint in an animal is called a 'hock.' It's the lower part of the 'Z' in an animal's hind leg.
- A dog's hindpaws are our toes. This is likewise with herbivores such as horses.
- An animal's hips and shoulders are typically in line with each other and most animals have a straight spine, with only a slight sway in it. If an animal's shoulders are significantly higher than its hips than it's probably a bulldog or an inbred german shepherd and thus not the model you should be using for your quadrupeds unless that's what you're going for. These anatomical features are caused by extremely bad breeding and usually lead to the animal dying of hip displacia - a condition not found in wild wolves!
- Animal skulls are longer than ours. If you're animating a creature's face, at least have a look at its skull, to figure out the range of movement they have. For carnivorous animals, keep in mind that their lower canines are closer to the front than their upper canines - a mistake that many animal artists make.



Basic musculature tip - when drawing in an animal's thigh, make it a sort of triangle from the side view angle.

2. Animating the Quadruped - Walks

Don actually did a pretty good job of describing a quadruped's walk. If you're in animation, then you know a basic biped walk is made up of four keys - the stride, the stretch, the crossover and the step. For quadrupeds, this is the same, but here are some stuff to keep in mind:

A. I firmly recommend mastering a biped walk before attempting a quadruped walk. This is common sense.
B. There are two major keys to a quadruped's walk; when a animal's forequarters are in CROSSOVER its hindquarters are in STRIDE - and vice versa. These are the two keys you should be working with as you key out your animation!
C. When legs are in CROSSOVER the head or tail next to it goes DOWN. When the legs are in STRIDE the head or tail goes UP.

Refer to the illustrations in my white board notes.




3. Quadruped Jump

To animate a quadruped's jump, first anticipate by having the character crouch a little, then like a diver, spring it forwards. This is where you can show you know your hang time, as animals can jump a lot further and higher than we can. Keep in mind that it is physically impossible for all the joints in a quadruped's leg to align in a straight line. Not only that, but this looks awful! PLEASE DO NOT DRAW THIS! EVER! Stretch with the body, NOT the legs!!! Keep a slight zig-zag in the legs! Animals are extremely flexible, especially if they're predators like wolves or especially cats - use this to your advantage for great animation!

As your animal is completing its magnificent arc of a jump, or hop, make it contact the ground with one fore foot first, than roll it onto the other. Animals do this naturally and it's an adaption to transfer the force of their own weight to avoid injury. If your animal is jumping from a standstill, it's okay to have the front feet pretty close together and only have one frame worth of roll, but if your animal is using speed to jump there should be a noticeable roll. This concept is especially important if you ever animate a gallop. Keep track of your animal's lead legs! The back lead will be the opposite of the front. Also, just to be even more confusing, animals often change leads mid gallop when encountering an obstacle, but to simplify your animation I would strongly suggest avoiding this.

The best live footage reference for jumping in quadrupeds is equestrian show jumping. Here we see Canadian Olympic Gold Medalist Eric Lamaze and his fantastic stallion Hickstead demonstrating the different kinds of contacts in a jump. (Also a fairly good resource for gallops.)



And here are my white board notes, as well as my final quadruped assignment from last year:




5. The Gallop.

Unless you closely study your own gait in comparison to an animal's gallop, I doubt there is any way that you would see how alike they actually are. Animals hit the ground with their lead legs first, then roll onto their inferior leg. As they put their full weight onto their inferior, the dominant limb is brought up into the air and as the animal's momentum carries it forwards, its inferior limb becomes airborne too, passing the lead leg as it contacts the ground again. It's extremely important to remember that during an animal's gallop there is always a point when all four feet are off the ground. The gallop is an extremely powerful gait, superior to our own rather pathetic run. For every galloping stride a horse takes, we must take three or even five. Cheetahs can run up to 100 kilometres per hour, thanks to the amazing flexibility of their spines. To learn the gallop, I strongly recommend watching live action footage, as most of the examples found in animation are extremely poor. Animators who can draw a decent gallop cycle are extremely rare as as you well know, most of us specialize in bipeds.

If you insist on watching animation to study the quadruped gallop, the best animation of this anywhere can be found in the Dreamworks film SPIRIT; Stallion of the Cimarron. The animation in this film is simply magnificent and even if you don't like horses, if you intend to animate a quadruped, this movie is a trove for study. Here's a general example of the entire movie.



For live action material, I strongly suggest the movie Seabiscuit but as this film can be a tad boring, I suggest looking up clips from it on youtube for study. Here's a good one. Just like Spirit, Seabiscuit has a lot of excellent perspectives of the gallop and has the best cinamatography of horse racing ever filmed. In a horse race, what does a horse do? RUN FULL OUT! That's why footage of horse racing is excellent for reference. All animals gallop in essentially the same way, their bone lengths are simply different.





For canines, I strongly suggest studying wolves rather than dogs. Wolves have a fluidity in their movement which most dog breeds have lost due to improper breeding by humans. Just like horses, wolves are pure poetry in motion, an expensive ferrari next to a dog's lumbering model T. Of course, another excellent species for study is the cheetah. If you're studying a specific animal, please research footage of it! You'll find it extremely helpful.







Technically speaking, a quadruped gallop should be on ones or twos, depending on exactly how fast you want the animal to look.

6. Other Gaits

Besides the walk and the gallop, quadrupeds have two other default gaits; the trot and the canter or lope. Canters, which while at first glance look much alike to the gallop, are in fact different. They are slower than a gallop and a trot is slower than a canter. I have not yet had reason to study these gaits, but I can make a note that during the trot, an important key happens when the front and back ends of a quadruped are doing the opposite motion at the same time, so that the hindquarter on the right may appear to reach out to the right forequarter, which reaches back. At the same time, the left hindquarter is stretched out behind and the left forequarter is stretched out ahead. Logically, I would simply reverse these to get the second key. To study a trot, I suggest looking up footage of horses first. Here's some.







Why are trots important? Because as gaits go, animals are more likely to trot than walk when moving over long distances. It's energetically more economical, which is an important thing when you don't know when or where your next meal is going to be. The human equivalent of a trot is a jog, but unfortunately, our jog pales in comparison - in fact, it's much easier for a human to hike than it is to jog. (Hiking is simply an extended version of a biped walk and is our evolutionary answer to travelling long distance economically.)

7. Notes to Remember....
- When designing a quadruped character, always first seek out to understand the animal you are basing it off of. If you intend to animate that animal, find out how it moves! Research!
- Remember important landmarks. The fetlock (wrist joint) is extremely vital to a quadruped's movements - do NOT forget it!
- If you're having trouble, animate one end of the animal first, than the other. Add tail and head later. (If you have a solid, true understanding of the creature and how it moves you shouldn't have to do this however.)
- The basic shape of an animal's leg is a 'Z.' However, don't use this as a template; remember at all times how long each part of the limb is supposed to be. Forequarters and hindquarters are DIFFERENT.
- Wild and domesticated animals move differently. Domestic animals are much less graceful than wild ones, which must depend on stealth for survival. However, animals like horses and cats are an exception to this rule. A wolf's gait will always be more fluid than a dog's, whose original anatomy has been butchered by human stupidity over the centuries.
- When designing a predatory animal, keep this in mind; all wild carnivores typically have large paws, which they need for stability when running through difficult soft terrain such as sand and snow. Their toes may even splay slightly on contact. Domestic carnivores tend to have smaller paws, since their ability to run swiftly has lost its value in their evolution.
- Please remember; when animating facial expressions on an animal, remember that they use their entire body when conveying emotion to each other. The raising of an animal's tail might say that they are victorious or dominant, while the lowering of it between the hindquarters says that an animal is feeling insecure or afraid. Also, canines wag their tails when they are happy, but a cat twitches the very tip to show that it is annoyed or concentrating on prey. Likewise, animals use their ears; pricked up ears show that an animal is alert and paying attention, while the laying back of an animal's ears can show that it is angry or scared. Animals flatten their ears like this in order to protect them from being torn during combat. Also, an animal's ear will turn towards an object of attention before it will actually look at it - their ears are nearly always in motion. A wild animal who isn't alert to its surroundings is a dead one. In terms of full body, an animal will cower or lower its head when it is afraid, but puff itself up to make itself look bigger when its angry - this is called a threat display. Dogs even have special muscles along their spine from their forehead to their shoulders to even their hips which let them make their fur stand straight up - this is called hackling and the area is called hackles.

8. Suggested Studying Material

- 'The Art of Animal Drawing' by Ken Hultgren - superior to the Capilano book list's 'How to Draw Animals,' this book has the distinction of having actually been written by an animator. It's full of beautiful structural and anatomical drawings, as well as demonstrations on how animals move. It's an excellent book, with lots of insightful help.

- 'SPIRIT; Stallion of the Cimarron' Dreamworks SKG. - the best animated resource for quadrupeds in existence.

- 'Lady & The Tramp' Disney - with gorgeous canine animation, this film is a gem for study, back from the day when Disney animators actually really knew how to draw animals!

- 'The Lion King' Disney - with a cast made up almost completely of quadrupeds, this film is another fantastic resource for quad animation! There's one sequence with Simba galloping in slow motion that would be particularly helpful.

- 'Seabiscuit' Dreamworks SKG, Universal & Spyglass Entertainment - fantastic cinamatography makes this a fabulous resource for quadruped animation. This film was a landmark in the history of racehorse film work and shows it with multiple ingenious perspectives which can certainly help you if you're going for something more imaginative.

- Youtube - for all your miscellaneous studying needs.


In closing, here's one last full look at my white board notes, thanks again to Rachel.



Thank you for reading. While I wish to someday explore the subject of drawing quadrupeds in more depth, this is all I can manage for now. In the future, I plan to write a full art book about drawing these creatures, written in a way that explains how they work to non-quadruped artists. I myself learned to draw quadrupeds before I ever even attempted a biped and find and understand them much better than I ever have bipeds. I only learned to draw bipeds when I began the writing of my manuscript Emperor's Blood which has an almost entirely biped cast. Nowadays, I can draw bipeds that are on par with my quads, but quads will forever be my strength in animation and art.

Hopefully you find these notes helpful.

-Rosanna P. Brost