A wild boar has drowned after swimming for half an hour in a cold lake downtown in east China's Hangzhou City.

Huang, a cleaner, noticed an animal swimming in the middle of the famous West Lake and reported it to the city's waters management office on Tuesday afternoon. The office and the district's public security bureau then sent patrol boats to rescue the buoyant boar.

Startled by the incoming boats, the beast upped its swimming pace and headed away from its would-be rescuers until exhaustion and the freezing water dragged it to its watery end. The city had its first snow of the winter just one day before.

Staff from Hangzhou Zoo hastened to the scene with tranquilizer darts but by the time they arrived, the pig had perished. The body was retrieved and taken away.

Hangzhou, described by Marco Polo as "the City of Heaven," is famous for its cultural landscape and scenery. Though in the center of the city, the West Lake was visited by wild boar at least three times in 2005, 2007 and 2011, according to previous reports.

A lack of natural enemies, well-preserved vegetation on surrounding hills and the ban on hunting around the lake are thought to be the contributory factors for the more frequent appearance of wild boar in the city.