The great hammerhead shark, sphyrna mokarra, was named by Eduard Ruppell in 1837, for its distinctive hammer-shaped head. (Sphyrna is Greek for "hammer".) The great hammerhead is a large shark, with an average length of 7 feet. Its head blade is proportionately wide, over one-third of the shark's total length. The hammerhead's unique features make them excellent subjects for depiction with modelling clay. By using an air-drying clay and a few common household objects, you can create your own hammerhead model.
Prepare a clean, dry, flat work area to work with the clay. Air-hardening clay is tacky to the touch and can easily absorb small objects.
Take a large amount of clay out of the airtight clay container, and flatten it with the rolling pin. Wrap the flattened clay around the paper towel roll to form the body of the hammerhead shark.
Remove a smaller amount of clay from the container, about a third of the size of the shark body. Roll it into a tube shape. Press the toothpick into the side of the tube, midway between the ends. This forms the shallow notch that distinguishes the great hammerhead from the scalloped or smooth hammerhead sharks.
Poke small holes for eyes at each end of the tube. Bend the tube to be slightly bowed outward, to form the distinctive arched shape common to all hammerheads.
Flatten another large amount of clay with the rolling pin.
Cut out the dorsal, pectoral, pelvic fins and tail fin. Use your fingers to shape the fins, and set each one aside. The first dorsal fin should be larger than all the other fins, and have a moderately curved rear margin. Shape a second dorsal fin, about half the height of the first. Create two smaller, stubbier fins pelvic fins, and two slightly larger pectoral fins. Form a tail fin, which is the size of the dorsal fin and pelvic fin, combined. Pinch the top end of the tail fin to form a hook shape at the tip.
Create slip by mixing some of the clay with water, and stirring until the mixture has the consistency of double cream. Slip is used to help join clay pieces.
Dab a small amount of slip on the shark body, the curved side of the headpiece and the underside of each fin, as you attach them to the shark body. Attach the first dorsal fin on the top of the shark, about one-third of the way from the head. The pectoral fins attach low on each side of the body, slightly forward of the first dorsal fin. The second dorsal fin attaches on the top of the body, close to the tail fin at the back. Attach the anal fin to the bottom, approximately the same length along the body as the second dorsal fin. Attach the remaining pelvic fin one-third of the distance between the rearmost pelvic fin and the pectoral fins.
Use the toothpick to scratch vertical gill lines on each side of the body, just in front of each pelvic fin.
Allow at least 24 hours for your model to dry and harden completely.
Thicker pieces of clay are more durable than thinner ones. Make the fins at least 1/4 inch thick.
Keep clay away from an open flame, because it is flammable. Air-dry clay cannot be kiln fired or oven dried. Unused clay should be stored in its container, to prevent drying out. Dried clay should not be exposed to liquids or food.