 Ants that got this procedure almost all lived, while similarly injured ants that were kept away from ant medics almost all died. Lab experiments showed these amputations work by preventing a wound's infection from spreading to the rest of the ant's body. Nell Greenfield-Boyce, NPR News. Critical features prices lost ground today. Oil down 57 cents a barrel to end the session at 82.81 a barrel in New York. I'm Jack Spear, NPR News in Washington.