I was researching some stuff online and found several enquiries for tutorials on sculpting animals. Since this is one of the subjects I enjoying sculpting the most I thought I could could offer some helpful tips.
I approach each animal I sculpt differently but there are some main considerations. Polymer clay is soft and gets even softer as you work it, especially Sculpey III, which is the brand I use since it's the only brand that comes in ivory (I don't like mixing my own colors, too much time wasted not sculpting). So the first and foremost thing to think about is keeping a light touch. I usually grab more clay than I need and use part of it for a handle, that way I'm not getting my main piece of sculpture too soft or squishing any previous areas I've worked on. I also try to use tools more than my fingers.
I start by squishing a general shape with my fingers and then move to using one of three main tools (very technical...a toothpick, a needle tool with a flat spoon shape on the other end and a curved soft acrylic (plastic) covering from a boomerang magnet that separated from the main piece...a rubber hand sized scraping tool will work too, but the black ones can stain your clay). The toothpick can make holes, but it is most useful as a rolling tool...I lay it sideways on the clay and twirl it in my fingers, allowing it to travel along a curve or edge. It's very nice for smoothing any area, no matter how tight a space you have to work in. Oops, I forgot my other important tool...an artist paintbrush...I used a soft one for light smoothing and a stiffer one for stippling but mostly I use the handle for making round indented holes (smoothing (like the toothpick) is great too, but cheap handles will transfer color to the clay).
If you use the rounded edge of a brush to make a shallow indentation and then slightly lift the clay you will have formed a ridge around the hole...this becomes eye lids later on, after adding too hardened eye balls. I grab two same size globs of clay for the eyes, roll one in each hand and then put them under a hairdryer in a glass jar for a couple minutes...this way you don't lose the shape when molding around them. I don't always add eyes...deep undercuts are what makes a sculpture work best. You can create an eye shape and let the shadows that the cut makes create your eye effect.
I usually do the head, body and limbs separately and then join them. You don't really want a round ball for the head, you want an egg shape, with the wider part on top. For this chimp I started that way and then added a half ball for the mouth area. I didn't have a photo for the back of a chimp, so I just thought about what a toddler looked like from the rear and then just made the bottom of the 'tailbone' turn into a little stump of a tail. I didn't add the ears until the whole sculpture was finished...too easy to moosh by mistake. I just made a flat circle and then used the toothpick to make a question mark just inside the edge and then used the end of the paintbrush to push in into the head...this created the tunnel of the ear. Then I just curved the ear and gave the bottom round area a little pinch...ears are hard to paint but not very hard to sculpt...they just look hard :)
If you are doing something with a snout like a dog, then the 'egg' lays on it's side and you press the snout area inwards. I think and work in shapes...a dog is a square block that steps down into a narrower block with the end curving back to the jaw. The ears are ovals, the body an elongated egg wider at the top. I tend to smooth the legs for a curvy flow, but it's very important to get the correct positions (dog knees in the rear bend backwards). I didn't have a photo of the back of this dog either, but I just thought about how a rib cage flares and used that as a guide.
The frog was really a much simpler piece to do, both the head and the body are oval shapes that taper at either end...the eyelids are done with the paintbrush end, balls then added. The nostrils are done the same way, but with a toothpick, the mouth is just a single rolling side to side motion of the needle tool.
I don't copy reference photos, but I use them to make sure I get a realistic shape...I always change the pose to suit what I'm working on. With sculpture it's best to use your instincts...you've seen many dogs and cats, if you get stuck then close your eyes and think about trailing your hand along the body as you pet it...it will give you more insight that you realize.
Ok...that all sounds simple. But the difficulty is the medium you are working with. After a couple times you will know when the clay is getting too soft to work with. When this happens it's time for a 15 minute break...you just pop your clay in the freezer while you relax. The fridge works too, but takes longer. Clay doesn't freeze but it gets nice and hard...when it first comes out it's a great time to get nice smooth edges or etch in some details. It doesn't take too long to soften up either. You can also pop a piece straight from the freezer to the oven...I do this sometimes at the end to give it a final little cleanup. It will sweat in the oven, but no harm done.
Sometimes I will do several bakings. If the head is very small and very detailed I might fire it first. As long as you are very careful to smooth the new clay over it, leaving no ridges, it works (that rolling toothpick works great here). The only issue is that sometimes a smaller piece will darken a touch more in the same amount of time...though this is rare. I rarely bake the limbs separately because they usually need a little shaping, though I will do hands and feet at the end and attach them, though not baking first.
Limbs have a couple requirements...the main shape is pretty straight, and it is cut into different upper and lower bones, each with an imaginary hinge in between. When you sculpt you need to look at it not only from all sides, but the top and bottom too. If you make a habit of doing this while you work then it all comes into a good form at the end. And usually you need to support the limbs or they will curve on their own (and fall out of shape in the oven). If I have support at two places (the shoulder and hand/paw touching another part of the body) then I don't always have to have a wire inside...unless it's long, then it will slump. I don't use wire all the way through usually...I just form the top bone and then insert a short piece of wire and then make the second bone seperate from the body and when it's mostly formed, push it onto the wire and form around it for the joint. Wire will work loose if you move it too much, so a good idea to use some liquid sculpey to help it bond in the oven. I will sometimes bake the body and head and then add raw clay for the arms, this allows you to lay the piece down or grip it tightly if needed. Or conversely you can use the freezer to help you out.
I do miniature work, so I don't worry about adding too much detail. The whole idea is to get 'essence' of whatever animal I am working on. You don't need to show every hair in the fur. I usually show none at all because our mind knows it's there even if we don't see it. If I need to I might pull some clay into a raised ragged edged shape to simulate a tail and maybe add a few lines for detail but that's rarely necessary.
Feet and hands are done with this in mind. I go very simple using either a little ball for a paw or elongated shape for a foot or hand. I slice into the side for opposable thumbs and then slightly round it. I take the toothpick and mark out the toes or fingers on top and then roll the toothpick longwise down the tip and then do the back...this way they're lined up. Then I just round the ends. If you look at the chimp it's quite effective...they're not realist, but they're real enough so that you mind says they're what they are. That is the balance you are looking for.
The main thing you want is personality. That can come from a certain tilt of the head or shape of the eye or mouth and most definitely the pose. When you start your piece think of what you think is cute about the subject. For me a chimp is a comedian...always in funny poses yet with an appealing little face. Frogs are limber and stretchy and get in almost impossible poses and yet always look like they are about to launch off in another direction. Dogs and cats sleep a lot lol...but that is when they usually look their sweetest. Yet when moving there is a sinuousness in cats and a loping appearance in dogs...all these things give the animal personality.
Movement is also important. There is a flow to movement...even a sleeping dog needs to look like it might start running in its sleep, so if you have the right flow to the body shape and limbs, then it looks like it has movement, even though it's a statue stuck in one position in the end.
Before you start really visualize what you want it to look like. I find a freedom in sculpting that I didn't have with painting...by knowing what the limbs and body look like I can shape it into almost any position I want by just thinking about it a little first. It's much easier to correct things in clay than paint too. If an arm isn't working, just pull it off and build a new one. And if the unthinkable happens, like a piece falling over in the oven, breaking a limb off...well you can either repair it and re-bake (and make it stronger in the process because of the re-bonding of the clay into one piece) or just add a new one on and no one but you will ever know. You can glue a piece on also, but I only use glue to hold a piece until baked (it doesn't work as an adhesive after baking) because why have a weak area with a crack when you can make it whole and strong? I will sometimes add an embellishment piece to the main body with glue if baking will not hold it as well, but that is rare.
After the piece is baked then you can sand it into a final shape...here is a chance to correct anything that is a little off and give everything a nice flow...again, look at it from all sides as you work. I start out with a rough carpenter sandpaper and then move right to a smooth wet/dry sandpaper for the final finish. I varnish with either a satin or matte acrylic varnish which also acts as a bonder for very thin delicate areas.
My advice is to start with something easy. The hummingbird at the top right corner of my blog was my first piece. It was fairly simple...a small ball on top of a larger ball. They still needed shaping and the beak was a killer but it was a good subject for a first piece. If you want to do a cat then do one sitting, with the limbs close to the body...this can be done so in the end it's essentially one piece. Work your way up to the hard stuff slowly and expect problems when you have 4 limbs going in different directions...there is nothing that can't be done though...it takes patience and ingenuity with problem solving but if you pay close attention to the shapes you will end up with a realistic looking animal in the end.