scientists at the University of Puerto Rico have developed a system to monitor wildlife in tropical rainforests, using captured audio in real time to remotely record the sounds made by animals. Using hardware that includes iPods, solar panels, and car batteries, the scientists created a network of radio-connected listening posts around the world that allows them to collect data 24 hours a day over long periods of time. The sound will help them track the effects of environmental changes—such as deforestation and climate change—on endangered species.