In an effort to revitalize its rapidly dwindling ranger population, officials at Yellowstone National Park unveiled a new mating program this week in hopes of doubling the endangered employees' numbers by 2015. 'It's vital we act now and save these once proud rangers before it's too late,' said National Park Service director Jonathan Jarvis, adding that his staff had already begun identifying alpha males, monitoring the fertility cycles of several females, and preparing specially designed enclosures that would encourage copulation. 'We've matched more than 15 active breeding pairs and now just have to wait and pray that they successfully mate.' Park sources also said that, if Friday's singles' mixer doesn't go well, some of the more resistant female rangers may have to be tranquilized and artificially inseminated. 