Experts issue warning after observing concerning change in bear behavior: 'Currently active'

Hibernation is commonly understood as related to seasonal change. But bears in parts of Japan may be seeing their routine wintertime sleep disrupted by the availability of food — human food.

What's happening?

"Last year, the city received its last report of a bear sighting in November," one city official said, according to Kyodo News. "This year, however, bears have continued to be spotted in December."

An increase in bear sightings across the country appears to be related, at least in part, to a delay in hibernation rituals, seemingly driven by more constant access to food sourced from residential areas. 

"Individual bears that are currently active have learned that there is still food in human dwellings," Naoki Onishi, of the Forestry and Forest Products Research Institute in Japan, told Kyodo. "With food available, bears are slow to enter hibernation."

Onishi also suggested that bears living in increasing proximity to residential areas may be woken from their winter sleep by loud human activity.

Why is this concerning?

Japan has seen significant increases in human-bear encounters over the past year, leading to unsafe situations for both animals and people. By the end of November, according to NBC News, a record-high 235 bear attacks had killed 13 people across the country in 2025.

Complicating the matter? While regular access to human food seems to be driving some of the sightings and encounters as of December, a lack of access to tree nuts and other staples of the bears' diets may have been the prime driver earlier in the year. 

With rising global temperatures and shifting weather patterns reportedly impacting tree nut production, bears may have become more familiar with human settlements long before they were due to hibernate, having wandered into cities and towns in search of food.

What's being done?

Addressing the dangerous human-wildlife encounters earlier in the year, the United States Embassy in Japan issued a warning in November, NBC reported. 

Other precautions have included signs warning of bears, residents wearing bells, and culling efforts. According to the outlet, there was at least one instance of residents "[chopping] down fruit and chestnut trees that might attract hungry bears" at a children's school. There, the principal also regularly "[set] off firecrackers and [played] human voices with a radio to scare [bears] away."

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In these ways, the chain reaction of ecological impacts is fairly clear. With that in mind, addressing the underlying issues may be the most prudent in the long term.

A broader shift to clean energy sources could help mitigate the rising temperatures that are compromising more typical bear foods growing far from human activity. Conserving larger swaths of land to serve as protected, food-rich habitats for bears may also help.

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