Abstract The people of northwestern Alaska have had a long relationship with local populations of Rangifer tarandus. During the last 200 years this relationship has changed from one of subsistence to overexploitation of caribou (the name for wild reindeer in North America), to commercial livestock production of semi domesticated reindeer and now may be returning to a subsistence economy based on caribou. Reindeer were introduced to Alaska in 1892 because of the disappearance of caribou, a subsistence resource. Until recently, reindeer meat and velvet antler production generated significant employment and revenue important to the economies of rural Alaskan communities. However, from 1976 to 1996 the Western Arctic Caribou Herd (WACH) increased from about 75,000 to 463,000 animals. Concurrently, winter range use of the WACH shifted westward onto traditional reindeer ranges of the Seward Peninsula for the first time in over 100 years. This event has produced socio-economic and ecological consequences for the region. Many reindeer herders have lost 75-100 percent of their herds through commingling and out-migration with wild caribou. This loss, amounting to over 17,000 reindeer, represents a potential economic value of millions of dollars. Many herders have adopted new technologies, such as satellite telemetry and intensive herding to salvage what is left of their herds. Here we discuss the role of grazing animals and patterns of human resource use in an Arctic system. We then discuss our findings on the effects and changes in management practices brought about by caribou incursion in the context of the regional economy on the Seward Peninsula.