Many invertebrates such as salamanders and starfish can regrow a body part if one is lost. This was also believed of jellyfish until experiments proved otherwise. Being symmetrical is a crucial characteristic of a moon jellyfish which is a necessity for movement and feeding. When two of the eight arms were removed from the jellyfish it did not proceed to regrow them. Instead it used its muscles to push and pull the remaining arms until they were once again evenly spaced. This new scientific phenomenon has been termed Symmetrization and it is how a jellyfish is able to heal itself.