By province, South Korea's southwestern province of North Jeolla topped the list of wild boars' habitat density with 8.7, trailed by the southeastern province of South Gyeongsang with 6.6 and the northeast province of Gangwon with 5.4. The institute defines 3 to 5 per square kilometers as a safe population density.

The increased habitat density stokes fears that people could be at risk of running into the feral animals more often.

On Sunday, a 58-year-old medicinal herb collector died from excessive bleeding after a wild boar bit his thigh on a mountain in the city of Samcheok on the country's east coast. The incident followed a December 2015 incident in which one of the two people were mauled to death by a wild boar while picking medicinal plants on a mountain in the same city.

Efforts to catch more wild boars than ever does not appear to help decrease the number of wild boars due to the prolific animal's propagative nature. In Gangwon, the estimated number of wild animals captured increased to 21,700 in 2015 from 10,700 in 2013 and 8,700 in 2011. As of September this year, it is estimated at 22,000, 5 percent of which is wild boars.

An official at the institute said, "A wild boar gives birth to three to 10 piglets. It is not so easy to adjust the number of the animals by capturing or hunting done on a local basis."

"A rise in the habitat density means that the possibility of people encountering wild boars could increase, too," the official said, asking people to take preventive measures to avoid such sudden encounters.

"On a mountain trail, which is also a passage of wild animals, you have to show indications of people approaching them as a way to keep them from appearing all of sudden," the official added. (Yonhap)