Two frisky white bears charmed and awed a throng of visitors who turned out yesterday morning for the grand opening of the new Polar Bear Exhibit at the Pittsburgh Zoo and PPG Aquarium.

	Lake Fong, Post-Gazette Matthew Robinson, 4, of Mooresville, N.C., gets an up-close look yesterday at a polar bear at the Pittsburgh Zoo and PPG Aquarium. Click photo for larger image. Zoo hours are 9 a.m. to 5 p.m., including today, Thanksgiving. Admission is $9 for adults, $8 for those over 60, $7 for children 2 to 13; under 2 are free.

At first, the bears were nowhere to be seen as a crowd gathered outside three large viewing windows at 10 a.m. But as soon as the brief speeches were made by Pittsburgh Mayor Luke Ravenstahl, Allegheny County Chief Executive Dan Onorato and Gary Claus, chairman of the zoo's board of directors, the cave door was opened.

One white head appeared in the cave entrance, then a second as the crowd oohed and aahed.

The bears slowly walked out onto the rocks. They sniffed the air and strolled over to greet children and adults waiting outside the upper viewing window. Kids and bears were nose-to-nose, to the envy of children waiting at other windows.

"The bears dive into the water about 15 to 20 minutes after they come outside," Barbara Baker, zoo president and chief executive officer, told the children assembled in front of windows at the lower end of the exhibit.

Each of the bears weighs about 600 pounds now, and they'll each double that weight two years from now, Dr. Baker said.

Koda and Nuka gamboled on rocks around their waterfall, rising up on hind legs to wrestle and play. They bear-hugged each other. As if on cue, they dove into their pool after about 15 minutes of dry-land play.

They swam right up to the lower-viewing windows, as if to greet their visitors. They wrestled in the water. They played with toys. They swam on top of the water and beneath it. They swam on their bellies, they swam on their backs and then they looked at their audience, as if to gauge the reaction.

"They are hams and they do seem to enjoy the attention," said Mark McDonough, one of their keepers.

The friendly wrestling is behavior keepers had not seen until the young bears went out on their new exhibit last Thursday for a news media preview, said Kathy Suthard, head keeper of the polar bears and the big cats. The bears have been frolicking in the exhibit since then, she said, though the viewing windows had been covered over until the official opening yesterday.

More than 5,000 people have submitted entries in the zoo's rename-the-bears contest. They were born at the Denver Zoo and have been at the Pittsburgh Zoo since June. The polar bear exhibit is part of a $12.5 million Water's Edge exhibit, which has been under construction for two years. Separate exhibits for sea otters and walruses will open next year.

About 2,600 visitors passed through the zoo gates by early afternoon yesterday. Average weekday attendance is 2,500 to 3,000. Zoo officials are expecting 8,000 to 10,000 visitors this weekend.

The bear brothers will be 2 years old tomorrow and their birthday party is open to the public from 11 a.m. to 3 p.m. Starting at 11 a.m. commemorative cookies will be handed out, while supplies last. The birthday cake will be cut at 1:45 p.m. while visitors sing happy birthday to the bears.

On Saturday and Sunday the zoo will have live entertainment and activities from 11 a.m. to 3 p.m., including ice sculpting demonstrations and crafts. Santa Claus will visit the zoo both days from 11 a.m. to noon and Frosty the Snowman from 1 to 2 p.m.