An introduction to the Fortymile Caribou Herd

Above the tree line, wind sweeps through the grassy tundra as hilltop rolls to hilltop, then to mountains beyond, purple in the distance. These highlands are where the Fortymile Caribou Herd (FCH) spend their summers. However, they do not stay in one place for long. Their range is vast, spanning 23,000 square miles, crossing international borders and fording rivers from the alpine tundra of Yukon, Canada to the boreal forests of eastern Alaska. Caribou are on the move. Caribou (rangifer tarandus), part of the deer family, live in northern latitudes around the globe. In Europe they are called "reindeer." In Alaska and Canada "reindeer" refers to domesticated animals and "caribou" are wild, but they are all the same species. Unique among deer, both male (bull) and female (cow) caribou grow antlers. Antlers of an adult bull are large and grand, and antlers of an adult cow are much smaller and thinner. Caribou have large, concave hoofs well-suited for traveling in soft tundra and snow, and act as paddles when swimming across rivers. Their hair contains air pockets which keep them warm and also gives them more buoyancy when swimming. Bulls usually weigh 350-400 pounds, and cows average 175-225 pounds. Alaska has 31 separate herds of caribou. Each herd has its own calving ground, returning to that place every Spring. The Fortymile Caribou Herd, named after the Fortymile River which runs through the herd's region, migrates hundreds of miles from the forests of eastern Alaska to their calving ground in the alpine tundra of western Yukon. Here they find fresh willow leaves, tundra flowers and mushrooms to feed upon. In late May or early June, the pregnant cows gather together for birthing. Cows give birth to a single calf. All the cows give birth at the same time so that predators may target stillborn or unhealthy calves, letting all the rest escape. Newborns can walk within an hour of birth and are quickly following Mom as she searches for food. Mothers shed their antlers after their calves are born. As Spring turns to Summer, the FMH is always on the move as thousands of caribou graze, always looking for more food. This is "insect season." Caribou find themselves constantly harassed by swarms of mosquitos. They must stop eating to shake their heads free of mosquitos, a brief moment of relief until the bugs return. Often caribou will huddle in large groups to find shelter from the mosquito attack, or they will abandon the good forage for the barren but windy heights where mosquitos do not follow. In late August/early September bull antlers shed their velvet (the fur covering on antlers), marking the beginning of the rut, or mating season. Flush with testosterone, bulls spar antlers to antlers. Deeper into September the fights get more serious as bulls claim space and the cows within that space. Losers may be injured. Victors mate. Large bulls shed their antlers soon after mating. Smaller bulls keep their antlers into winter. Colder weather signals the return to the wintering grounds in eastern Alaska. Once they decide to migrate, the FCH can travel 50 miles a day. Like other migrating species, they know the direction home, even if they do not follow exactly the same route. Back in the Alaskan forests, the herd disperses, calves staying with their mothers. Here caribou eat lichen and other vegetation found under the snow. Caribou are prey animals, hunted by wolves, bears and coyotes. And humans. The indigenous people of Alaska and Yukon, the Gwich'in, Koyukon and Tanana people, have hunted and revered the caribou for thousands of years. They relied on caribou for meat, clothing, tools and spiritual practices. These people are still here, though the traditional weapons of spears and hunting fences have been replaced with firearms. The governing authorities of both Alaska and Yukon respect their traditions and their subsistence rights. The population of the FCH has fluctuated through the decades. In the early 20th century, the FCH may have numbered 500,000. Overhunting, habitat decline and human development in their range followed. By the 1970s the FCH numbered a mere 5,000. Conservationists took action to reverse that alarming trend. Hunting regulations were established, including strict quotas and hunting seasons. Human impacts on caribou habitat caused by mining, logging and road construction came under rigid control. Predator control programs were initiated but were controversial. In 2018 the FCH had reached 82,000 caribou. However, population fluctuation continues as the caribou encounter new threats, such as climate change. The Fortymile Caribou Herd has roamed this land for ages past. With wise management, it will continue to follow the rhythms of summer to winter, west to east, tundra to forest for ages to come.