For decades, scientists have tried to solve a deadly puzzle: Why can’t highly intelligent blue whales avoid the collisions with ships that are a leading cause of mortality for the endangered marine mammals?  The short answer, according to a first-of-its-kind study, is that they have never learned to steer clear of big objects like ships. The largest animal that’s ever lived, at more than 100 feet long and 320,000 pounds, the blue whale for 30 million years never had to move out of anything’s way.