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Polar bears exhibit a tendency to engage with human constructions. A scientist delves into the reasons behind this behavior.(Image credit: Gerhard Kraus/Getty Images)Share this article 0Join the conversationFollow usAdd us as a preferred source on GoogleSubscribe to our newsletter
Polar bears are inherently inquisitive creatures. This inquisitiveness frequently leads them into proximity with humans, posing risks to both species.
As the Arctic’s climate undergoes warming, certain polar bears are spending extended periods on land, distanced from the sea ice environments they depend on for hunting seals. With nutritional deficiencies stemming from ice reduction, some ponder if these bears are compelled to undertake greater risks around human populations in their quest for sustenance, thereby escalating encounters and conflicts between polar bears and people. However, prior to this, research on this dynamic was scarce.
The initiative commenced at the behest of Parks Canada when their recently established field camps at Broad River and Owl River experienced a higher number of bear visits than anticipated. These camps had been strategically positioned away from the coast to diminish the probability of polar bear encounters, making the resolution of this immediate query a paramount concern.
We explored whether human presence, the duration of the ice-free period, or a combination of both factors influenced polar bear visits. In approximately 80% of the observed bear visits, our photographs provided sufficient detail of the animal to assess its body condition using a recognized fatness index.
Our cameras documented 580 bear visits, predominantly occurring between July and November, periods when the species is known to be prevalent in the region. Our findings indicated that the presence of humans at the camps and the CNSC had no discernible impact on the volume of bear visits. Conversely, the length of the ice-free season each year demonstrated a significant influence.
It’s all about ice
The ice-free season can be prolonged if sea ice melts earlier in the spring than usual, freezes later in the autumn than usual, or a combination of both. Throughout our study duration, no long-term trend in the length of the ice-free season was evident, yet it exhibited considerable year-to-year variability. We determined that the more extended the period western Hudson Bay remained free of ice in a given year, the greater the frequency of bear visits to our study areas.
Suboptimal body condition is regarded as an indicator of nutritional duress, and a robust body condition for enduring onshore fasting is vital for polar bear survival.
However, instead of observing visits from bears in poorer condition that were noticeably leaner—which was our expectation—we discovered that the more time bears spent off the ice, the more inclined all bears were to approach our study locations, irrespective of their nutritional status.
This outcome was unanticipated, given that other research suggests underweight polar bears are more prone to attacking humans, interpreted as those specific bears taking greater risks to secure food and thus being more likely to approach or prey upon people.
The investigation suggests that polar bears in poor physical condition are more likely to engage with humans.
(Image credit: Prisma Bildagentur/UIG via Getty Images)
Instead, it appears that body condition might play a different role. Rather than prompting bears to seek out human contact, body condition may instead influence the escalation of interactions between people and polar bears.
Put another way, if polar bears are in the vicinity of humans, a lean bear might exhibit a greater propensity to aggressively attempt to secure human food sources, or even target people, compared to a bear experiencing less nutritional stress.
We were also surprised by the scarcity of lone sub-adult bears in our photographic evidence. Other studies have similarly indicated that these younger individuals are typically the ones most frequently involved in conflicts with humans.
These observations, however, are consistent with other research concerning this specific sub-population. As the ice-free period has generally extended in western Hudson Bay, the birth rate and survival of juvenile bears have declined. Our unexpected findings are thus likely attributable to a simple lack of young bears within the population during our study period.
Scientific and Indigenous observations
Our findings imply that the reduction of sea ice probably does not lead to an increase in interactions with people solely because polar bears are thinner or more famished; therefore, we need to gain a better understanding of the factors that can cause interactions to devolve into attacks.
What are the implications of this for current strategies aimed at mitigating the risk of polar bear-human conflicts? Returning to Parks Canada’s initial inquiry, it seems that the probability of bear visits to their camps is not influenced by any human-controllable factors, but the outcomes of any subsequent bear visits are indeed subject to human influence.
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Our discoveries may also shed light on why scientific explanations and observations from Indigenous and local communities regarding polar bear-human interactions have diverged. Scientific literature has long posited that poor physical condition drives polar bears toward northern settlements.
Conversely, documented accounts from these communities suggest that the bears entering communities are not necessarily in worse condition than would be expected.
Our findings exhibit greater alignment with Indigenous observations, underscoring how unsubstantiated assumptions, through repeated assertion in scientific literature, can become entrenched as accepted truths.
This edited article is republished from The Conversation under a Creative Commons license. Read the original article.