The decrease in Arctic ice as a result of global warming has already taken it’s toll on polar bears, leaving them with fewer habitats and increased difficulty in finding food. But scientists have now discovered a larger, and potentially more lethal, threat to the Arctic mammal. They discovered that the immune system of polar bears is unable to adjust to new pathogens that have come about as a result of rising temperatures. Professor Diana Weber at New College of Florida, together with a large group of international researchers, studied the immune system of 98 polar bears in Canada.