The Virginia opossum is the only marsupial indigenous to North America. As if carrying their young in an abdominal pouch isn't odd enough, their ability to withstand poisonous snake bites, such as rattlesnakes and copperheads, is also unusual but very useful. Yet even if they are able to avoid predators and vehicles, opossums have only a brief lifespan of about 2 years. Most don't survive past their first birthday. When on Roanoke Island make it a point to visit National Wildlife Refuges Visitor Center.