Nepenthes rajah is a carnivorous pitcher plant species endemic to Borneo. Its most distinctive features - giant urn-shaped traps, called pitchers, containing water and digestive fluid - allow it to catch and digest insects and even small vertebrates and mammals. These pitchers also host a number of organisms with which it is thought to form symbiotic relationships. Called nepenthebionts, many of these organisms are so specialized that they cannot survive anywhere else.