Over the past 15 years, the reported harvest by native and non-native people has ranged from 2000 to 7000 head per year. Despite having a comparable birth rate, the Porcupine Caribou Herd has not grown as quickly as other barren ground caribou herds. This suggests that the Porcupine herd experiences greater mortality than other barren ground caribou herds. The main predators on caribou are wolves and humans. Since the local wolf population is relatively low, they do not have a large effect on caribou populations, taking between three and five percent of the herd each year.
Human hunters take between two and three percent of the herd each year.
Over this period, the spring mean body weight of female caribou declined, providing evidence that environmental stresses on adult caribou are limiting current growth of the herd. When environmental conditions such as snow fall make it difficult to reach their coastal calving plains , as seen in 1987 and in the early 1990s, the caribou give birth in areas where predator numbers are higher. Scientists predict that global warming may cause the Northern Yukon to have greater snowfall in winter, faster melt period in spring and warmer summers. Already, scientists are noting earlier snowmelts and a general increase in the biomass of green vegetation at calving areas. Elsewhere in the arctic, global warming models predict that the habitat of the Peary caribou on Bathrust Island will experience heavier snowfalls and more freezing rain.