Up until the mid-1990s, the ecosystem of Yellowstone National Park had turned into a gloomy, barren land, overgrazed and overpopulated by elk. But ever since wolves were reintroduced in the park, the ...

Get any of our free daily email newsletters — news headlines, opinion, e-edition, obituaries and more. Scientific research has long assumed gray wolves are non-migratory during springtime, staying ...