Experts are still searching for the cause behind a string of North Atlantic right whale deaths in the Gulf of St. Lawrence. The Marine Animal Response Society says three of the six endangered animals have been hauled to shore for post-mortem examinations. One was found off Norway, PEI. The group says it’s not releasing the results until it concludes its investigation. North Atlantic right whales are among the most endangered large mammals on Earth, with only about 500 still alive.