Snake Island, located in the core area of the Laotie Mountain National Nature Reserve in northeastern China's Liaoning Province, is home to nearly 20,000 viper snakes unique to China. The snake island has become a stopover for migrant birds to rest and seek food on their way to the south in autumn. A large number of migratory birds provide enough food for the island's viper snakes, forming a special island ecosystem with the viper snakes as the top consumer.