The frigid waters of the Arctic are home to near-mythical creatures, sometimes called the "unicorns of the sea" for the long, ivory tusk that spirals several feet out of the top of their heads. Worldwide there are only about 50,000 to 80,000 narwhals, as they are more commonly known, with about two-thirds of these whales summering in the fjords and inlets of Nunavut in northern Canada. Scientists are hoping to learn more about narwhals through a new effort to track them as they move around the icy waters of northern Canada, as well as more about how declining amounts of...