Polar Bear Visits to Camps Driven by Ice-Free Season Not Hunger

A decade-long study in Wapusk National Park, Manitoba recorded 580 polar bear visits to trail camera sites and found that the length of the ice-free season, not the body condition of individual bears, determined how frequently bears approached human infrastructure. The findings challenge the widely held assumption that nutritional stress from sea ice loss is the primary driver of human-bear conflict risk.

Researchers placed trail cameras at three Parks Canada field camps and the Churchill Northern Studies Centre between 2011 and 2021, capturing 580 bear visits predominantly between July and November. In approximately 80 per cent of cases, photographs allowed researchers to rate each animal's body condition using an established fatness index. The study found that human activity at the camps had no effect on visit frequency, but longer ice-free seasons significantly increased the number of bear approaches regardless of how well-nourished the animals were.

The results complicate previous scientific assumptions. Earlier research had suggested that underweight bears were more likely to approach humans in search of food, which was interpreted as a direct link between climate change, nutritional stress and conflict escalation. The new study suggests that body condition may influence the outcome of encounters rather than their frequency: a hungry bear near people may be more likely to behave aggressively, but the decision to approach infrastructure in the first place appears driven by the cumulative duration of time spent off the sea ice.

The researchers note that their unexpected results may partly reflect demographic changes in the western Hudson Bay subpopulation, where extended ice-free seasons have reduced juvenile bear survival, meaning fewer high-risk young bears are present. The findings align more closely with Indigenous and community observations, which have long indicated that bears approaching settlements are not necessarily thin or starving. The authors conclude that managing conflict outcomes, through infrastructure design and encounter protocols, matters more than attempting to control the frequency of bear visits.

Key figure — 580 bear visits recorded over a decade