THE CLOSURE of Vancouver's Stanley Park Zoo is only one skirmish in the widening battle over the treatment of captive animals. Zoo and aquarium officials face unprecedented challenge from groups who feel that wild animals should not be displayed for human amusement. ----------------------------------------------------------------- VANCOUVER, British Columbia - If there is an animal equivalent of a ghost town, it is here at the Stanley Park Zoo.

Most of the tree-shaded wire cages and glass enclosures are empty, except for the ubiquitous squirrels and flocks of Canada geese resting for winter migration.

The whoosh of cars on the nearby road no longer is interrupted by monkey screams or arctic wolves' snarls.

The zoo's staff - manager Mike Mackintosh, his secretary and two keepers - is laboring to find new homes for the few animals left.

If a pending agreement to place all 21 Humboldt penguins in Chicago's Brookfield Zoo goes through, the animal population here will drop to one polar bear, Tuk.

At 34, he is too old to move and will live out his life in the concrete pit that has been his home since 1962.

When he dies, so will this facility, the first - but perhaps not the last - major municipal zoo in North America to be killed by the animal-rights movement.

In 1993, Vancouver voters decided by a 54 percent majority to close the zoo after a campaign inspired by the notion that wild animals ought not be displayed primarily for the entertainment of people.

The closure is only one of the events that places Vancouver on the advance lines of the battle over the treatment of captive animals.

The conflicts that have erupted here are being replicated across the continent. Zoo and aquarium officials face unprecedented scrutiny and challenge - and not just from animal-rights advocates.

"There are more and more people questioning whether zoos are good things, whether they do what they purport to, and even what use they are at all. And these are questions that also are being asked within the industry," says Rob Laidlaw, director of Toronto-based Zoocheck Canada, which monitors zoo conditions throughout Canada.

There is a revolution under way in thinking among zoo directors, says Michael Hutchins, director of conservation science for the American Zoo and Aquarium Association, a Bethesda, Md., organization representing 168 U.S. and Canadian institutions.

The anti-zoo movement is driven by evidence that many wild animals simply do not adapt well to captivity.

Animal advocates, led by the British-based Born Free Foundation, have documented and publicized neurotic, self-destructive zoo-animal behavior such as relentless pacing and rocking, head twisting, gnawing on bars and walls, even self-mutilation.

"We have to move away from the idea that we have the right to walk down the street and view an elephant," Laidlaw says. "It's not a right, it's a privilege, and it should always be a priority that the animal's rights are put first."

Zoo critics go on to attack the scientific underpinnings of captive breeding and educational programs, which many officials cite as justification for keeping zoos.

One study, for example, concluded that the $16,800 it takes to keep a rare black rhino in a captive breeding program for a year could protect the natural habitat for 16 rhinos.

Moreover, captive breeding remains a chancy proposition: Despite the millions of dollars spent, so far only 16 species have been successfully reintroduced into the wild.

Zoo administrators often counter that animal-rights advocates are steeped more in sentiment than science, but they are reaching some similar conclusions about the need for change.

Hutchins points to new exhibits in Seattle, Atlanta and other top zoos that display animals in elaborate, expensive settings that mimic rain forests and woodlands rather than what he calls the "tiled bathrooms of the '50s and '60s."

Zoo-based wildlife researchers are also spending more time and money in places such as South America and Africa, seeking to transfer knowledge gained from animals in captivity to beasts in the wild. In the last four years, zoo scientists have produced 1,300 articles on biology and conservation techniques applicable to animals in nature, Hutchins said.

Some zoo officials even admit to second thoughts about whether certain species - bears are a frequently cited example - should be kept in captivity at all. But most continue to defend zoos and aquariums, albeit mainly on consciousness-raising grounds rather than as entertainment.

"My feeling on animals is, I'd rather see every one of them free in nature, but nature ain't what it used to be, and that's our fault, humans' fault," says John Nightingale, executive director of the Vancouver Aquarium, another target of activists. "You can't work to change that if you don't care about it. You can't care about it if you don't know about it. . . . And that's what zoos and aquariums are all about, the unique ability to experience a living thing. So Vancouver is a poorer place because we're missing one part of that."

Perhaps, but for the animal-rights movement, the Stanley Park Zoo presented an easy target.

Few, including its staff, could argue in defense of the 21-acre collection of sterile cages, wire enclosures and moated pits. The zoo's origins can be traced to 1893, when a park warden chained a captured black bear to a tree stump for the edification of locals.

The current architecture dates to the 1950s and '60s. Through the '80s and '90s, the facility was often criticized as being outdated and substandard.

But repeated proposals by administrators to renovate the Vancouver zoo never moved from desktop to blacktop, blocked by money shortages and declining public support and attendance.

The last plan called for conversion of the zoo into an "animal conservation center" specializing in local species.

To many in this city, which celebrates its intimacy with nature, such a zoo seemed superfluous.

Vancouver is spread across a broad peninsula, facing the Pacific and backed by mountain ranges; a 45-minute drive inland can bring residents face-to-whiskers with animals in the wild.

Vancouver has also proven receptive to the animal-rights movement.

The city and all but one of its suburbs have outlawed appearances by circuses with performing animals. Several communities adopted ordinances setting minimum standards for privately owned pets. Anti-hunting commercials air on local television. The daily newspaper, The Vancouver Sun, features a regular column on animal protection issues.

"Vancouver is a very passionate place," aquarium director Nightingale says. "You don't find people in this city who say, `Who cares?' "

When it comes to animals, Ingrid Pollak clearly does.

The leader of the anti-zoo campaign is cool and elegant, her voice carrying a trace of her native Germany. Pollak moved to the front rank of Vancouver's animal-rights movement in the mid-1980s, when she dropped out of the Society for the Prevention of Cruelty to Animals because she considered it too meek.

She describes her group, the all-volunteer Vancouver Humane Society, as "like a union for animals. When animals come into conflict with people, we always side with the animals."

As for zoos, she hews an uncompromising line.

"We don't need zoos in our society," she says crisply. "I would close them all down, and I don't think wildlife would be any worse off. I'm not going to say animals never should be in captivity. If captivity is in the interest of the animals, there are situations where it can be just."

Perhaps surprisingly, she has nothing but praise for Mackintosh, the zoo manager, who she says "is to be congratulated" for the careful, humane way he has relocated Vancouver's collection.