Expert expresses concern about possible ninja bear apprentices adopting its hunting practices.

Japan’s northernmost prefecture of Hokkaido is home to much of the country’s bear population. But while there are a lot of bears in Hokkaido, only one of them is known as the “Ninja Bear.”

No one has ever seen the Ninja Bear directly, but images of the stealthy animal were captured on security footage in the town of Shibecha this past July, as shown in the video below at the 7 and 12-second marks. This was the first time the bear had been seen since 2019, when it was also seen on security camera footage in the town (as shown at the 26-second mark).

But while it’s the Ninja Bear’s skill at avoiding detection that earned it its nickname, the moniker would be just as appropriate for its penchant for midnight assassinations. Based on paw tracks, DNA samples from fur and droppings, and attack methodology, the Ninja Bear is suspected of roughly 60 attacks on dairy cows at farms in Shibecha and the neighboring town of Akkeshi.

The Ninja Bear is also known as Oso 18, a reference to its initial on-camera sighting taking place in Shibecha’s Ososhibetsu district and the fact that its front paw tracks measure 18 centimeters (7.1 inches) across. That makes it an especially large bear for Japan, with experts estimating its weight is about 300 kilograms (661 pounds).

▼ The Ninja Bear’s tracks, and a dairy cow that was clawed by the bear but survived the attack.

60 bear attacks on livestock in the course of three years in two small towns is an exceptionally high number, according to Masami Yamanaka, director of Hokkaido’s Shiretoko Brown Bear Association. In an average year, the rest of Hokkaido as a whole sees only about a dozen or so such incidents, he says.

Also unusual is what the bear does after making a kill. Yamanaka says that ordinarily a bear that makes a kill larger than what it can eat at one feeding will remain in the area until it gets hungry again. The Ninja Bear, though, often eats just a portion of the cows it kills and then disappears back into the forest, only for its next attack to take place in a different part of the two-town area.

▼ The map with markers here shows where some of the incidents have taken place.

The Ninja Bear is also suspected to be adept at walking in rivers so as not to leave tracks, and in an attack that took place in July appears to have known to dig a hole in the soil to slip underneath an electrified fence. Its unpredictable movement has frustrated hunters’ animal-control efforts, and at least one dairy farm has deployed one of Japan’s robot Monster Wolves as a precaution.

Despite their omnivore status, it’s unusual for bears in Hokkaido to attack dairy cows, especially with the frequency that the Ninja Bear is striking. Yoshikazu Sato, a professor of wildlife ecology at Rakuno Gakuen University, has expressed concerns regarding bears’ mental capacity to learn from each other’s behavior (such as cubs being taught how to hunt by their mothers). If another bear were to observe the Ninja Bear successfully attacking dairy cows, or come across the carcass of one following an attack, they could in turn begin copying the behavior, essentially giving rise to a ninja bear clan.

Sources: YouTube/ANNnewsCH, Tele Asa News via Yahoo! Japan News, Yahoo! Japan News/HBC Hokkaido Hoso, YouTube/STVニュース北海道
Top image: Pakutaso
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