SAPPORO--Increased sightings of brown bears in Hokkaido in winter suggest the animals are awakening earlier from hibernation or not hibernating at all, putting forestry workers in wilderness areas at greater risk of being attacked, experts say.

The reason bears are roaming forested areas earlier than usual is apparently due to unchecked numbers of Ezo shika deer that offer an alternative food source to their mainly herbivore diet. 

With February marking the forestry ministry getting back into full swing in and after February, prefectural authorities are calling on workers to be extra vigilant when they are out and about.

ABUNDANT FOOD SOURCES

The Ground Self-Defense Force’s Camp Rumoi alerted the nearby Rumoi police station around 3 p.m. on Feb. 10 that its members spotted a brown bear during a cross-country training run at a ski slope in the Kamui-iwa Koen park in Rumoi.

According to the city government and the local planning section of the prefectural police, two GSDF members saw a 2-meter-long brown bear ambling toward the mountain.

It was only 30 meters from the cross-country course.

“(Brown bears) haven’t been seen in the city in February for more than 10 years,” a city official said.

Police said they received a total of 17 calls about brown bear sightings in Hokkaido between January and February from 2016 to 2021.

As of Feb. 15 this year, there had been three sightings.

“Brown bear sightings in mid-winter in mountain forests in eastern Hokkaido began about 10 years ago,” said Toshio Tsubota, a professor of animal medicine at Hokkaido University’s Graduate School who is well-versed in brown bears’ hibernation and breeding habits.

Tsubota is also a member of the Minami-Shiretoko Ezo Brown Bear Information Center, a nonprofit organization based in Shibetsu, eastern Hokkaido.

Brown bears have also been spotted in winter in areas surrounding the town.

“In recent years, it would seem that a number of brown bears awaken from hibernation early or do not go into hibernation at all,” Tsubota added.

The bear activity in winter months is almost certainly due to the growing population of Ezo shika deer, he said.

About 90 percent of a brown bear’s diet consists of acorns, grasses and other plants.

When plants are thin on the ground in winter due to heavy snow, bears hibernate by slowing down their metabolism and lying motionless.

In contrast, polar bears in the Arctic reach a state of prolonged torpor in summer because they are unable to capture seals, their primary food source.

“Basically, bears in zoos remain active during winter. They don’t have to hibernate when they have no trouble finding food,” Tsubota said.

According to the Natural Environment Division at the Hokkaido prefectural government, the number of Ezo shika deer in Hokkaido excluding the southern region doubled from fiscal 2000 to 770,000 in fiscal 2011.

Deer start reproducing at around two years old and give birth every year.

The fact they have few natural enemies also contributed to their numbers.

However, the deer population has been decreasing in recent years due to culling. In fiscal 2020, the deer population was estimated to be 670,000.

The figure is almost 57 times the 11,700 estimated number for brown bears.

According to Tsubota, it is possible that brown bears are awakening from hibernation early and more often after being stimulated by the footsteps and smell of Ezo shika deer passing nearby.

Ezo shika deer are more agile than brown bears, but they are not so adept at traveling in snow-covered trails, making them easy prey for brown bears in areas where there is deep accumulated snow.

In January, the chewed carcass of an Ezo shika deer was found in a mountain area near Shibetsu, officials said.

Because accumulated snow hardens and makes forestry work easier from February, field work and survey activities pick up pace.

Male forestry workers were attacked by bears on two occasions between January and February 2015, resulting one death.

Both times, the workers got too close to dens where brown bears were hibernating and woke them up.

‘AVOID WORKING ALONE’

“Since you may encounter brown bears even in winter, we recommend that you have someone to act as a lookout when you work,” said an official at the prefectural government’s Natural Environment Division. “If possible, have a hunter accompany you.”

The official also expressed concern about Ezo shika deer whose remains are left where they fell after being hunted.

The prefectural government receives reports every year of deer remains abandoned by hunters by the roadside.

It is possible that brown bears haunt the same spots to feed on the carcasses.

“Leaving (deer remains) on the road is against the waste management law. They must be disposed of appropriately,” the official said.

Tsubota said most brown bears hibernate until around March.

“There is no need to fret too much, but I can’t really say there is a zero possibility of an encounter with a brown bear in a human settlement during the snow season,” he added.