Sustainability What Is a Species? To this day, scientists struggle with that question. A better definition can influence which animals make the endangered list By Carl Zimmer THIS IS A PREVIEW. Buy this digital issue or subscribe to access the full article. Already a subscriber or purchased this issue? Sign In JUSTINE COOPER; CANIS INSETS: W. PERRY CONWAY Corbis (left); ALGONQUIN PARK MUSEUM (center); RICHARD HAMILTON SMITH Corbis (right) If you visit Algonquin Provincial Park in Ontario, you may hear the high, lonesome howls of wolves. You may even be lucky enough to catch a glimpse of a distant pack racing through the forests. But when you show off your blurry pictures back home, what species should you boast that you saw? Depending on the scientist you ask, you may get a different answer. Some may even offer you a few different answers all at once. In the 18th century European naturalists dubbed the wolves of Canada and the eastern U.S. Canis lycaon, because they seemed distinct from Canis lupus, the gray wolf of Europe and Asia. By the early 1900s North American naturalists had decided that they were actually gray wolves as well. But in the past few years Canadian researchers who have analyzed wolf DNA have come full circle. They argue that gray wolves only live in western North America. The wolves of Algonquin Provincial Park belong to a separate species, which they want to call C. lycaon once more. THIS IS A PREVIEW. Buy this digital issue or subscribe to access the full article. Already a subscriber or purchased this issue? Sign In Buy Digital Issue $7.99 Add To Cart Print + DigitalAll Access $99.99 Subscribe ADVERTISEMENT Scientific American is a trademark of Scientific American, Inc., used with permission © 2015 Scientific American, a Division of Nature America, Inc. All Rights Reserved.