SHIBECHA, Hokkaido—Exhibiting traits of a serial killer, an elusive and cunning bear has continued to terrorize a dairy region in eastern Hokkaido this summer.

Named OSO18, the bear has attacked 65 grazing dairy cattle over the past four years, killing 31 of them.

Experts estimate the predator is a 10-year-old male brown bear measuring a relatively large 2 meters tall and weighing 300 kilograms.

It has also shown signs of above-average intelligence.

The bear only attacks at night when detection is much more difficult. In fact, OSO18 has been seen in the wild by humans just once, and it knows how to avoid traps.

OSO18 shows no signs of ending its bovine-butchery spree.

On July 1, three dairy cows were attacked at a ranch in the Arekinai district here. Two of them died.

By Sept. 12 this summer, eight cows had been mauled, five fatally, in the towns of Shibecha and Akkeshi.

DNA tests on brown bear hair samples found at the attack sites and other information since 2019 indicate that OSO18 was the culprit for most of the killings.

OSO18’s footprints were found after its first known attack in July 2019, when a cow was killed at a ranch in the Osotsubetsu district here.

The bear’s name is derived from a part of the district’s name, and its foot width of 18 centimeters.

It was one of 28 cattle killed by OSO18 in 2019, followed by five in 2020, and 24 in Shibecha and Akkeshi in 2021.

Most of the incidents have occurred between June and September.

Farmers in the area generally allow cattle to stay in pastures even at night during the summer months, but that has made them easy targets for the brown bear.

The bear is attacking cattle mainly for food. The victims’ intestines have been eaten from their sliced-open backs, according to the Shibecha town office’s agriculture and forestry division.

However, OSO18 also appears to kill for no practical purpose.

“OSO18 seems to be fixated on cattle intestines,” a town official said. “But it sometimes kills and leaves the carcass without eating it.”

Brown bears have a habit of hiding food in the ground for later consumption. OSO18 has not exhibited such behavior, the official said.

Shibecha town officials set up box-shaped iron cages containing food in several locations to trap the bear. But security camera footage showed OSO18 shunning the snares.

Ranch operators have also set up devices that emit sound and light signals to chase away approaching predators, but to no avail.

The bear’s midnight-to-dawn hunting period when it can go unseen underscores its cautious nature.

A ranch worker around the site of the first attack in July 2019 is believed to be the only person who has seen OSO18.

The area where the attacks are concentrated is dotted with ranches nestled in mountain forests.

Ambushing and killing OSO18 is difficult because the bear can move extensively, hidden from view, town officials said.

Ranch operators are struggling to come up with measures to prevent further attacks.

Local dairy farmers have entrusted 1,700 of their cows to the Akkeshi municipal ranch, where the animals can graze in three pastures covering about 1,000 hectares.

After four cows were mauled to death at the ranch in July and August last year, about 800 cattle were temporarily placed in cowsheds.

According to manager Tadahiro Sakurai, 57, the ranch in May this year used state subsidies and other means to set up electric fences in about 10 locations where bear attacks have occurred. The fencing, extending a total of 23 kilometers, surrounds about 150 hectares.

“Electric fences require maintenance work, such as removing undergrowth to prevent electric leakage. We can’t fully enclose all areas because we have a limited number of staff,” he said.

There have been no bear attacks at the ranch so far this summer.

“We can’t feel safe yet because OSO18 is elusive,” Sakurai continued. “Municipal officials and experts are taking action to capture it. For our part, all we can do is devote ourselves to defense and believe there will be no damage.”

Since April, Shibecha and Akkeshi town officials have stepped up efforts to trace OSO18’s travel route.

Taking advantage of the brown bear’s habit of rubbing its back against trees, the officials have set up “hair traps” by stringing barbed wire around trees to collect samples.

When they learn where and how OSO18 travels, they can decide where to place snares and take other countermeasures.