Observe a photograph of the animal you'd like to sculpt. Make special note of the general shape of the head, legs, body and tail.
Use aluminum foil to create the base for both the head and the body. By using the foil to create the "skeleton" of the sculpture, you will use much less clay on the sculpture and therefore save money. Roll the foil into whatever the general shape of the animal's body is. For example, a horse would have cylinder-shaped bases for both the body and head, and a frog would have rounder ones.
Roll out some polymer clay using a clay rolling tool or a rolling pin. When the clay is in a sheet that's about 1/4 inch thick, use a scalpel to cut the sheet into multiple, smaller sheets. Wrap sheets of the clay around the aluminum foil bases, pinching the ends together so that they clay holds. Roll the end of a clay blending tool over the connecting crease until it disappears completely. Use your fingertip to buff the clay and blend it further.
Connect the head piece to the body using the blending tool to mold the edges together. Use your hands to roll pieces of clay to use as the limbs of the animal. After the general shape is created, connect it to the body and use the scalpel to cut away any excess clay. Use the sides of the scalpel and the blending tool to form the shape of the legs.
Create any smaller clay details such as ears or tail. Ears can be made fairly easily using a triangle-shaped piece of clay with the two outer corners folded inwards. Small black beads can be pressed into the clay face of the animal for eyes.
Use the scalpel tip to draw in any distinctive features of the animals. Show contours or wrinkles in the animal's face, make the hooves or claws apparent, and glide the tip of the scalpel across the clay in small wisps to create a fur effect.