Algae-dyed polar bears puzzle Japan zoo visitors

Polar bears, their fur stained with algae, stand in their cage at Higashiyama Zoo in Nagoya, central Japan, Saturday, Sept. 6, 2008. Three polar bears at the zoo changed their colors in July after swimming in a pond with an overgrowth of algae, prompting many questions from visitors concerned about whether the animals are sick or carrying mold, a zoo official said. [Agencies]

A polar bear, its fur stained with algae, stands in its cage at Higashiyama Zoo in Nagoya, central Japan, Saturday, Sept. 6, 2008. Three polar bears at the zoo changed their colors in July after swimming in a pond with an overgrowth of algae, prompting many questions from visitors concerned about whether the animals are sick or carrying mold, a zoo official said. [Agencies]

TOKYO -- Green polar bears are drawing questions from puzzled visitors at a Japanese zoo. Three normally white polar bears at Higashiyama Zoo and Botanical Gardens in central Japan changed their color in July after swimming in a pond with an overgrowth of algae.

The sight of green polar bears has prompted many questions from visitors concerned about whether the animals are sick or carrying mold, zoo official Masami Kurobe said Sunday.

"Visitors seem to be shocked by the color, and we are asked every day why they are so green," he said.

High temperatures in July and August and less-frequent water changes because of the zoo's conservation efforts caused an algae growth in the bear pond and safety moat, Kurobe said.

Algae that enters hollow spaces in the bears' fur is hard to rinse off, he said.

The bears are expected to return to their natural color when the algae growth subsides in November, Kurobe said.