The Arctic Circle isn't the only place where polar bears are on the wane.

A drop in the captive population of those great white denizens of the north, along with higher-than-expected construction costs, is causing the Buffalo Zoo to reconfigure Arctic Edge to house fewer polar bears than previously envisioned.

Probably just a single family.

The exhibit instead will be filled out with other kinds of animals from the frozen tundra -- perhaps arctic wolves or foxes in combination with reindeer, arctic hares, snowy owls, or bald eagles and lesser animals.

"It will still be a really cool polar bear exhibit," pledged Zoo President Donna M. Fernandes.

The zoo had planned to divide Arctic Edge, the central feature of its next redevelopment phase, between a polar bear area with a saltwater pool and a grizzly bear enclosure with fresh water. Because two older grizzlies currently residing at the zoo do not fit in the long-range plan, their portion eventually would have been changed to accommodate more polar bears.

But for reasons that are unclear, "there just aren't that many polar bears in need of housing" in the zoo world, Fernandes said.

It may be that fewer orphans are being captured in arctic settlement areas than in the past or that breeding has been restricted under the global survival plan for the bears, "but I don't know for sure," she said.

A second factor was the added cost of installing and operating separate saltwater and freshwater facilities for one exhibit. "It's a lot of redundancy," Fernandes said.

Though the polar bear sections of the old bear pits have freshwater pools, modern husbandry standards require that any new exhibit featuring the species have saltwater because it's part of their natural habitat, she said.

Having separate water supplies would raise the operating costs of Arctic Edge, which will replace the ancient bear pits, by $75,000 a year, Fernandes estimated.

The grizzlies are nearing the end of their life span and will be placed in other zoos if they are alive when the exhibit -- already three years behind the original schedule -- is completed in about two years, she said. They won't be replaced.

Reshaping Arctic Edge to accommodate "maybe a male, female and offspring but not a larger group" of polar bears will not reduce the footprint of what is expected to be the
main attraction in the second phase of the zoo's $70 million, multiyear reconstruction program, she said.

Work on the new facilities is scheduled to start later this year.

A new polar bear family may already be in the making after the recent introduction of Nanuq, a 22-year-old male imported a year ago from the Henry Vilas Zoo in Madison, Wis., to the 9-year-old resident female, Anana.

Born in the wild and rescued as an orphan along with his twin brother, Nanuq never sired cubs in Madison despite being housed with a female. Because his genes are considered valuable to the captive population, officials of both zoos hope that romance blossoms and that he and Anana will restart Buffalo's once-prolific polar bear breeding program.

The program was suspended in 1997 because the captive population had almost too many Buffalo-born animals.