India, May 25 -- Birds do it. Bees do it. Even hibernating bears do it. They self-medicate, and they do it better than us. Bears, for instance, eat willow bark after their long winter snooze. Rich in salicin, the bark helps cleanse the bear's system and ease the stiffness and aches that may have set in, during the still winter months. Incidentally, salicylic acid drawn from salicin is used in our painkillers too; it's helped us make aspirin since 1899. Now to more dramatic examples. Florida carpenter ants perform surgery on each other, to increase an injured buddy's chances of survival. A study published in the journal Current Biology last year detailed how an ant will bite off an injured colleague's infected upper leg to save its life, wit...