Experts in the U.S. and Canada are still puzzling over what’s sickening ringed seals and walrus in the Arctic. Dozens of seals have died from the mysterious disease. A small percentage of walrus are ill with something that looks very similar, but no walrus deaths have been tied to the disease. Several labs in the U.S. and Canada have been unable to figure out what’s causing the illness in both species.Listen for the full storyDownload Audio