Forget hungry, hungry hippos — here come the hungry, hungry elk. Three national parks in Colorado and the Dakotas are awash in antlered gluttons, at some places more than twice what’s considered a preferable population. “Willow and aspen stands are declining [and] that deprives other species of habitat they need,” says a spokesperson for Colorado’s Rocky Mountain National Park. “We have to manage for the others … beaver, butterfly, a variety of birds, insects. It’s a whole ecosystem concept, and it can get out of whack.” Nature extremes in the form of drought or severe snowfall can sometimes help reduce elk populations, as can shipping the animals elsewhere, injecting them with contraceptives, or introducing predators. Nonetheless, park managers plan to move forward with more-reliable, always-controversial “lethal reduction.”