This is a HUGE difference. Starch peanuts are perfectly fine, but Styrofoam will get ingested and can cause blockages. The test is easy - put one of the peanuts in water. If it dissolves, it is made from starch and all is good. If it simply floats, seal them up and get them out of the house! Think Styrofoam coffee cup - with a half live of a couple thousand years. You definitely do not want your ferrets playing with and eating Styrofoam! Larry Anderson Scales and Tails Rescue [Posted in FML 7606]