Hainan gibbons are primates that live in the tree canopies on China’s Hainan Island. They are critically endangered, and forest fragmentation due to human activities could have further imperiled them by breaking them into smaller breeding populations. Scientists installed a rope bridge to serve as an elevated highway for the gibbons to cross from one forest area to another without having to descend to the ground, where they could be hit by cars or attacked by dogs. After 176 days, the gibbons caught onto the rope bridge and started using it to cross the gully. Based on this success, researchers are considering the rope bridge as a possible tool that could be used for other primate conservation groups.