Choosing faux fur or a soft animal print fabric will add to the realism of your caveman costume, and these materials are usually comfortable to wear. While you make your costume, remember that a real caveman would have created his clothing from animal skins and crude stitching, so don't worry about any small mistakes. Rough edges or uneven stitches may even add character to your finished caveman costume.
Measure around the widest part of your body with a tape measure. Add 8 inches to this measurement and then divide it in half. For example, if your body measurement is 40 inches, your final measurement is 24 inches (40+8 = 48/2 = 24).
Measure from the hollow of your neck to the point on your body where you want the hem of your costume to be located. Add 4 inches to this measurement and double it. As an example, 50 inches becomes 108 inches (50+4 = 54*2 = 108).
Cut a rectangle of fabric using the measurements from Steps 1 and 2. Using this example, the rectangle would measure 24 inches by 108 inches.
Fold the fabric rectangle in half by bringing the shorter ends together. Keep the wrong side of the fabric facing out.
Sew the sides of the rectangle together using a 1/2-inch seam allowance. Start your stitching approximately 1ft. from the folded edge and continue to the bottom of the rectangle. This will sew the sides of the caveman costume together while leaving openings for your arms.
Mark the centre 10 inches along the folded edge of the rectangle and trim along the folded fabric in this area to create a neck hole.
Turn the fabric right-side out and try on the caveman costume. If the neck hole is too small, use scissors to make it larger.
Accessorise the costume with plastic bones, leather belts, beads or feathers.