Simplify the following text for a Grade 11 native English-speaking person.
Original: Although remains of the Polynesian Rat in New Zealand were dated to over 2000 years old during the 1990s , which was much earlier than the accepted dates for Polynesian migrations to New Zealand , this finding has been overturned by later research showing that the rat was introduced to both of the country 's main islands around AD 1280 .
Simplified: The Polynesian Rat , or Pacific Rat ( Rattus exulans ) , known to the MÄ ori as kiore , is the third most widespread species of rat in the world behind the Brown Rat and Black rat . The Polynesian Rat originates in Southeast Asia but , like its cousins , has become well traveled - infiltrating most Polynesian islands , New Zealand , Fiji , and even Hawaii .