An illegal global trade in python skins is threatening the survival of some species of the snake, a report by a U.N. subsidiary organization says. Researchers with the International Trade Center, part of the World Trade Organization, say a growing demand for handbags and other fashion items in Europe is fueling imports of snake skins but the trade is so poorly regulated it is extremely difficult to establish whether the skins have been obtained legally or illegally, the BBC reported. Although international agreements do allow for some trade in python species, the rules are widely circumvented, the ITC report said. While snakes bred in captivity can be sold, there is evidence many so-called captive pythons actually come from the wild, it said. The snakeskin business is extremely lucrative, and an estimated half-million python skins make their way from Southeast Asia to the world market in a business worth $1 billion a year. Poor enforcement of existing legislation exacerbates the problem, the researchers said. \"It is up to the local authorities to enforce the laws,\" report co-author Olivier Caillabet said. \"A lot of the time they don\'t have the capacity in terms of money, people or expertise. \"And sometimes they just don\'t care.\"