Migratory caribou herds are named after their birthing grounds. In this case it is the Porcupine River, which runs through a large part of the range of the Porcupine herd. The herd has been losing numbers in recent years. In 1989 they numbered about 178,000. The estimates for 2010 numbered them at about 169,000. They migrate over a year between their winter range and calving grounds on the Beaufort Sea. It is the longest land migration route of any land mammal on earth. Their range spans across the Alaska/Yukon border. They are jointly managed by Alaska, Canada and local Native American peoples. They are important food for the Gwichʼin. They are a First Nations/Alaska Native people, who traditionally follow the caribou. The herd is also routinely hunted by other peoples, including the Inupiat, Inuvialuit, Hän, and Northern Tutchone.