PORTLAND, Ore. -- The Oregon Zoo is offering free admission to cyclists in a special event designed to bring attention to the plight of polar bears and support Metro's "Drive Less, Save More" campaign.

Photo by Michael Durham, courtesy of the Oregon Zoo.

A polar bear frolics at the Oregon Zoo.

The 2nd annual Bike for Bears event will be held on June 21, from 10 a.m. to 2 p.m. and anyone who uses a bike as his or her main method of transportation to the zoo will get free admission. Participants can ride their bikes the entire distance or ride part way and board the MAX.

Between 10 and 11 a.m., visitors can watch as zookeepers give the polar bears fun treats and toys, including faux bikes with tires made from barrels, hula hoops and sturdy car-wash strips.

The polar bear treats will also include a "Ride Your Bike to the Beach" theme as the three bears get sand, beach towels and plastic chairs to play with and, most likely, destroy.

"When zoo visitors encounter these amazing polar bears, we hope they connect with them in a way that inspires new insight and a desire to help," said Oregon Zoo Director Tony Vecchio. "People must care about an issue before they'll be moved to act."

According to Vecchio, the primary threat to polar bears is climate change. He explained that the sea ice is arriving later and later in the season and melting sooner, which is putting greater stress on the bears.

Bike for Bears also brings attention to Metro's "Drive Less, Save More" effort, designed to increase public awareness about the personal benefits of reducing single-person car trips.

Metro Councilor Robert Liberty, a long-time bike commuter, encouraged the public to take part and said riding a bike to the zoo isn't as challenging as one might think.

He said cyclists can use well-marked bike lanes on roads, or they can skip the hill climb and ride to their nearest TriMet stop and place their bike on a bus or MAX train.

"Riding your bike is a great way to get some exercise, see a different view of Portland and reduce pollution," said Liberty. "It's a win, win, win."

A $2 valet bike-parking service will also be available for participating cyclists.