Porcupine caribou

Porcupine caribou

Grant's caribou


Rangifer tarandus granti

The Porcupine caribou or Grant's caribou (Rangifer tarandus granti ) is a subspecies of the reindeer or caribou found in Alaska, United States, and Yukon and the Northwest Territories, Canada. It resembles the subspecies known as the barren-ground caribou (R. t. groenlandicus ) and is sometimes included in it.

Show More

Migratory caribou herds are named after their calving 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 1,500 mi (2,400 km) a year between their winter range and calving grounds at the Beaufort Sea, the longest land migration route of any land mammal on Earth. Their range spans the Alaska-Yukon border and is a valued resource cooperatively managed by the Alaska Department of Fish and Game, Canadian wildlife agencies and local aboriginal peoples. The caribou are the primary sustenance of the Gwichʼin, a First Nations/Alaska Native people, who traditionally built their communities to align with the caribou's migration patterns. They are also routinely hunted by other indigenous peoples, including the Inupiat, the Inuvialuit, the Hän and the Northern Tutchone.

Show Less



The Porcupine herd range covers 1,500 mi (2,400 km), from the calving grounds, the Porcupine River after which they are named, to "the river valleys and slopes in the Ogilvie and Richardson Mountains in the Yukon and the southern Brooks Range in Alaska." The calving area is located on 1.5 million acres (0.61 million ha) in the Porcupine River coastal region of the Beaufort Sea known as the 1002 area, which is part of the Arctic National Wildlife Refuge. The area runs through a large part of the range of the Porcupine herd.

Show More

In the spring the pregnant cows move "northeast from the Alaskan winter ranges or north and northwest from the Canadian winter ranges. If snowmelt is early, they will then move westward along the north slope of the Brooks Range into Alaska."

Most Porcupine caribou calves are born in the first week of June and they are at their most vulnerable from their primary predators on the calving ground—golden eagles, grizzly bears and wolves—during the first three weeks when they are dependent on milk from their mothers. About one quarter of them die during this period.  Their 1,500-mile (2,400 km) annual land migration between their winter range in the boreal forests of Alaska and Yukon over the mountains to the coastal plain and their calving grounds on the Beaufort Sea coastal plain, is the longest of any land mammal on earth.

Show Less
Porcupine caribou habitat map
Porcupine caribou habitat map
Porcupine caribou
Attribution License

Habits and Lifestyle

Seasonal behavior

Diet and Nutrition


Population threats

Climate change and the increased frequency of extreme weather events, such as unprecedented late slow melting, negatively affect the Porcupine herd. As a result there was "very high early calf mortality."  The primary predators for calves are golden eagles, grizzly bears and wolves. "Caribou exposed to industrial development shift away from the pipelines and roads." The passage of the provision opening ANWR's 1002 to oil and gas drilling is considered to be a threat. In 2001, some biologists feared development in the Refuge would "push caribou into the foothills, where calves would be more prone to predation." In their 2005 report, Russell and McNeil reiterated concerns that new calving areas would make the herd more vulnerable, as area 1002 provides a much higher quality of diet conditions than the alternatives in Canada.

Population number

By July 2017, the Porcupine herd had reached a record high of about 202,000 to 235,000 animals. Sixteen years earlier, in 2001 the same herd was only half as large. While other barren-ground caribou herds have declined by 90%, the Porcupine herd has remained relatively stable.

Coloring Pages


1. Porcupine caribou Wikipedia article - https://en.wikipedia.org/wiki/Porcupine_caribou

More Fascinating Animals to Learn About