It's a common belief that lemmings commit suicide by flinging themselves off cliffs en masse. However, this isn't actually true. Like most of us, lemmings are quite keen to stay alive, but their existence may threatened by climate change. The little rodents live up in the Arctic, and so the Wildlife Conservation Society thinks that they may be susceptible to the impact of changing climate. A change in the lemming population could have big knock-on effects in the wider ecosystem, as they are an important food source for a number of predators, including arctic foxes, birds of prey, weasels, wolverines, and grizzly bears. In fact, the population of many predators fluctuates in response to dips in lemming numbers.The most important thing for lemmings is snow. They live in deep snow burrows, so the snow has to be thick enough to insulate them from the cold. If snow arrives late, or melts early, then this could actually mean more chilly spells for the lemmings. Also, unusual warm weather in the Arctic winter means freezing rain, and cycles of thawing an freezing. This can coat plants with ice, meaning the lemmings can't eat their usual food.Next month, the Wildlife Conservation Society plan to launch a major study to look at how the lemming population, and their predators, are changing. It's one part of a large Canadian project, called the Arctic Wildlife Observatories Linking Vulnerable Ecosystems, which gives you the rather clever acronym ArcticWOLVES.