AKITA (Yomiuri Shimbun/Asia News Network) - Animal experts warn that bears in Japan have become accustomed to such sounds as radios and the ringing of bells used by humans to frighten them away and now may instead be attracted by the sounds as a marker of human prey.
In Akita Prefecture, four people assumed to be victims of bear attacks were found dead between May and June.
Pieces of human flesh were found in the stomach of one of the bears suspected to have attacked the victims. Other people in the prefecture have been seriously injured in recent attacks.
Experts warn that administrative authorities should improve measures to prevent the recurrence of such incidents.
Professor Koji Yamazaki of the Tokyo University of Agriculture, who is in charge of research conducted by the Tokyo-based Japan Bear Network, said: "Entry into the areas where the incidents took place should have been strictly limited, and utmost efforts should have been made to kill bears suspected to have attacked people."
In recent attacks, five people have been killed or injured on a mountain in Kazuno in the prefecture. The municipal government asked the prefectural government on May 23 for permission to kill bears after a second fatal attack was confirmed.
On May 30, a third victim's body was found, and on June 10, a fourth victim's body was discovered.
Members of a local hunters association found a female bear, which was assumed to have attacked the people, near the fourth victim's body. They fatally shot the bear.
The bodies of the third and fourth victims were severely damaged, and it was pointed out that multiple bears had fed on them.
A necropsy performed on the female bear revealed pieces of human flesh in its stomach.
An official of the city government said: "The area where the incidents occurred is vast. Privately owned land plots as well as roads for residents' daily use are located in the area.
"There are also access paths to mountain areas. It would be unrealistic to totally ban entry into the area."
Commenting on the view that permission to kill the bear came too late, the official said: "We didn't recognise how serious the situation was. We didn't assume the bear might have fed on the bodies of the victims."
LESS WARY OF HUMANS
Normally, bears in nature are afraid of humans. But the experts said that some have become man-eaters and tend to regard humans as prey.
In 1988, a bear killed and fed on three people.
Said Prof Toru Oi of Ishikawa Prefectural University, who specialises in the protection and management of wild animals: "Bears eat mainly plants, and normally do not attack humans.
"However, because they are highly adaptable, they could come to regard humans as prey."
The sounds of bells and radios have long been assumed to be effective in frightening bears away. But experts point out this may no longer be true.
Veterinarian Takeshi Komatsu, 48, director of Ani Kuma Bokujo Kumakuma-en, a zoological park specialising in bears in Akita Prefecture, said: "I have recently heard that bears may even be attracted by the sounds of radios. They may have learned to associate the sounds with the presence of bento boxes or drinks around humans."
The Institute for Asian Black Bear Research and Preservation, a nonprofit organisation based in Hiroshima Prefecture, conducts research on damage caused by bears in Akita Prefecture.
Kazuhiko Maita, head of the institute, spotted a bear about 80cm long in the morning of July 12 near the site where the bodies of the first and second victims were found.
While he took about 10 photos of the bear, it did not appear to be frightened and casually walked away.
Because bears in Japan do not have natural enemies, they are not wary of other animals. Experts believe one reason bears are less wary of humans is that bear hunting has declined in recent years.
To cope with the change in bears' behaviour, the Shiretoko Nature Foundation, a Hokkaido-based entity that seeks to protect and conduct research on wild animals, has for more than 10 years rented out cans of liquid pepper spray to drive away bears.
Even though people need to be brave to use the spray, which must be used from 4m or 5m away, officials of the foundation said it has been highly effective in driving bears away.
About 2,600 sightings of bears were reported from April to June in the Tohoku region, nearly double the figure for the corresponding period last year. And in Akita, Yamagata and Miyagi prefectures, the number of sightings was the highest in the past 10 years.
In autumn last year, healthy trees such as beech, whose nuts are favoured by bears, were abundant. It is assumed that well-nourished mother bears actively moved around with their cubs after emerging from hibernation.
Animal experts assume this is one reason for the increased sightings.
On the other hand, the blooming conditions for beech trees this spring were poor. The Tohoku Regional Forest Office predicts that no beech nuts will be produced this autumn in Akita, Yamagata, Iwate and Miyagi prefectures. In Aomori Prefecture, beech nut production is predicted to be "extremely poor."
A shortage of beech nuts will mean more bears will be attracted to village forests in search of agricultural harvests. If this happens, higher levels of alert will be necessary.