San Francisco Frontiers - Swimming trunks: transparent tank shows paddling pachyderms

Visitors are often surprised to discover that elephants can swim, but the hefty creatures are very good at it, zoo manager Daisuke Takeuchi told AFP on Thursday.

The park's six Asian elephants swim daily in the summer months, sometimes entering the 65-metre (210-foot) canal -- the length of five buses parked in a line -- together.

"Especially on hot days, they can't wait to get in the water, so when the water is ready, they rush in energetically and splash," Takeuchi said.

The park, within sight of Mount Fuji in central Japan, installed the pool with transparent sides in 2015, and elephant keepers from Laos clean it and change the water daily.

Japan's scorching summers are getting hotter, and last month the country saw its warmest July since records began.

To cool down in the heat, elephants spray water on their bodies and flap their large ears like a fan, so the main purpose of bathing is to remove parasites and dirt from their skin.

Elephant expert Sanjeeta Sharma Pokharel, assistant professor of Asian and African Area Studies at Kyoto University, said elephants use their "remarkable" instinctive swimming skills to migrate across habitats by crossing rivers.

"But swimming may not be their daily activity, until and unless circumstances demand it," such as during floods, Sharma Pokharel said.

Elephants also use bodies of water when they have leg or other injuries, a habit which "helps in reducing the strain due to their body weight", she added.

Using their trunk to breathe means they can swim long distances, and "in the wild, they have no choice but to swim in search of food", Takeuchi said.

"But in our zoo, rather than searching for food, they swim for fun, and because their bodies get cooler and it feels good to cool down, they happily enter the water."

U.Campbell--SFF