 And here's why. Frank's lab experiments show that without amputation, infection from the open wound will spread and almost always be fatal. Interestingly, however, amputation is only life-saving when the injury is in the upper part of the leg. And the ants seem to know that because when the wound is lowered down, they won't amputate. Frank says it's really striking to him that not only can the ants perform amputations,