Many animals migrate in an effort to find food, a more hospitable climate, and most importantly, a place to breed. However, a herd of elk known as the Clarks Fork herd, made up of nearly 4,000 elk, are coming back from their Yellowstone National Park migration with fewer calves compared to those elks that do not migrate, which are known as resident elk. So why are the resident elk being considered more successful compared to migrating individuals in the same herd?