Nico got a kick out of holding a one-year-old gibbon (presumed toilet-trained) on his shoulder. If we had been to the Gibbon Rehabilitation Center earlier, we would not have been as happy to see these animals. We learned that Gibbons are an endangered species being eliminated rapidly in the wild. To capture these youngsters their mothers were probably killed. At about age six Gibbons become aggressive in captivity and are no longer useful in getting money from tourists so they are killed or abandoned.