Are Isle Royale's Wolves Chasing Extinction?

摘要

Since his graduate student days in 1971, Rolf Peterson has spent a few nights of every summer camped within earshot of wolf packs on Isle Royale, Michigan, in the northwestern corner of Lake Superior. It may be as early as the end of June that he hears the sound he's waiting for: high-pitched yips that stand out from the long, sonorous howls of adult wolves. The calls herald a new generation of pups joining the island's storied wolf population. For 40 years without fail, Peterson and his colleagues have heard those yips.