In July caribou migrate in large numbers south across which continent?
Porcupine caribou Porcupine caribou The Porcupine caribou or Grant's caribou ("Rangifer tarandus granti") is a subspecies of the reindeer (or the caribou in North America) found in Alaska, United States, and adjacent parts of Canada. It resembles the subspecies known as the barren-ground caribou ("R. t. groenlandicus") and is sometimes included in it. Migratory caribou herds are named after their birthing grounds, in this case the Porcupine River, which runs through a large part of the range of the Porcupine herd. Though numbers fluctuate, the herd comprises about 218,000 animals (based on a July 2017 photocensus). They migrate over a year between
Barren-ground caribou habitat and creates obstacles, preventing caribou from accessing annual feeding and breeding grounds. Unpredictable migration patterns also have negative impacts on Indigenous communities who depend on caribou as a source of income and food. An additional stressor on barren-ground caribou is the irritation from insect behaviour, which can dictate the movement and health of caribou during the summer months. Increased warming temperatures and early springs result in greater insect numbers. Insect harassment force caribou to migrate to areas which may still be covered in snow or ice, thereby reducing access to food. Caribou give birth in early spring when insect