Don't just create, build

Where do you begin? Well you don't have to start with all this detail when designing a character but I wanted something specific for my Troganite horse. It's the parts that make the whole when designing anything, and the saying is true that you can't build on a bad foundation, so even if it's a drawing of a biological structure it starts with a well adapted frame.

Head shapes

I better post some of the sketches I've been sitting on! I've been thinking about skull shapes for anthros for sometime. Previously I looked at the need for anthro skulls to have a cranial dimension like that of a human, if you're thinking intelligence it seems fitting to exaggerate an animals skull to hold a similar brain size to a humans.

The 2 small intermediate diagrams show the distinction of cranial size (red), 
nose/face area (blue) and jaw (green).

Animal skulls are much more elongated front to back than a human's. Where you'd draw an average human skull as a sphere with a box below for the jaw, for an anthro you're looking more at a ovoid with a box at the front. This is so you can retain the distinct facial features such as those elongated noses and jaws. You can break this idea down further into class (I take class to mean either carnivore, omnivore or herbivore). The main distinction between them being the required jaw size to tackle their specialised foods. As a general idea, jaws tend to get both longer and deeper with herbivores; more muscular action is needed to grind plant matter, so a large bone surface is required, their food is generally in a hard to reach place, hence the long face. For either class, starting with a skull similar to that of a human guarantees you'll retain an adequate brain size.

Taking this a little further the idea of snout length is certainly up to not only the species and the class but also to your own preference. Felines tend to have a much rounder short snout, canines have a more rectangular and thin snout. Length adaptation is up to you. For example, the sketches above are for carnivores, their main principle is that their jaws are thin and sleek with large forward pointing eyes however the length of the snout is undefined.

Jaws are nothing without teeth, and teeth are distinctly specialised for each class. There are a number of other more subtle differences than teeth to think about, especially if you want to be creating expressive characters. Jaw depth i've mentioned, however it's carnivores that tend to have a much larger jaw opening range to catch and eat pray. Useful for expressions showing rage and anger. Due to their large teeth, particularly their canines, carnivores have limited side to side motion which herbivore use to rotate their jaws to grind plant matter. Side to side motions are more or less reserved to show puzzlement or thinking. 

Ahhhhhh a splinter!

Huh?

Stature - Ribcage

The ribcage has only one major function and that's to act as a solid cavity in which the diaphragm can pull and push air into the lungs. Between human bipeds and any quadruped mammal the major difference in the ribcages are from the effects of gravity and the relative positioning of the forelimbs.

Both ribcages at the top are viewed from cranial to caudal, you could say a quadruped's deep and a human's wide. The bottom sketches show how the canine ribcage would compare as a biped.

It is unlikely that a canine ribcage could support the rise and fall, expansion and contraction needed if it were biped, it's adapted in the wrong plain. But I like the idea of adding some of these shapes to a biped ribcage. One starting point is the sternum, it builds that frontal plain of the chest - does it need to be vertical, could it be shorter? I number of differences between species exist but large differences are more likely to be due to the size of the organs the animal has.

I took a comparative view of a carnivore and herbivore. 

Take an equine, it's a prey species, its evolved to run, requires large volumes of oxygen to do so, it's ribcage is extensive to maximize its capacity. However, it's a herbivore, and needs a much larger gastro-intestinal (GI) tract for digestion. To aid this the sternum is comparatively shorter to the ribcage than in a canine this flares the ribcage, helping to fit those larger organs in. Our canine doesn't need a large GI tract or even needs to do a lot of running, it's ribcage accommodates for this.

I wanted to look and see how these species variations may shape our biped anthros.

A scribble of ideas, looking how to incorporate some form of shortened sternum or elongated ribcage as per the species.

 

For the moment I rested my focus on what creates the girth or volume of the chest, the relation of the 1st ribs, clavicles and sternum or what looks more like a 'collar and tie'. Drawing the 1st ribs from the spine to the sternum helps give the chest its volume. The length and angle of the sternum helps give our character a puffy chest or more space for a larger abdomen. 

Take a look at how flared they made the ribs on Tavros in the Narnia films. It's a high volume chest, certainly plenty of space for a herbivores GI tract.

Some ideas on larger herbivore types. That cervical curve is really going to dip if we make a character with those distinctive rounded shoulders with a neck in a 'stoop'. The nuchal ligaments are going to have to act like a crane arm to help stop that neck collapsing - it's rather unstable. So I've also highlighted some context as to large stabilising muscle shapes of the neck. I think this would really limit head rotation. Also the cervical vertebra in this configuration would have to be bulkier to take the stress of the lateral rotation.

Great video on cervical spine rotation.

Skull Ideas

The muscles of the jaw are rather large on animals both herbivore and carnivore.
This is important for the Zygometic Arch or cheek bone as both the Masseter and Temporal muscles influence its size and shape. Coloured are ideas on visual fields.

I want to make sure a human size brain could fit into something like a horse's skull but make sure that the mouth and nasal pathways were still usable. By enlarging the Occipital or base of the skull can accommodated this. The brow ridge may also help but it means losing the flat Frontal bone that give herbivores their distinctive sloping head shapes.