SEATTLE - On a sunny July day, Chai the elephant browses on grass and branches in the one-acre elephant exhibit at Seattle's Woodland Park Zoo. Children lean over the metal barriers, trying to reach the enormous charismatic creature.

In the nearby elephant barn, Watoto stretches her trunk to a net filled with vegetation and munches on her lunch before wandering back to the outdoor exhibit. Teenagers watch her, mimicking the movements of her trunk.

Zoos showcase such scenes as evidence of the healthy and happy experience of their elephantsy. Animals rights groups dismiss such enclosures as woefully small and harmful to the health of creatures meant to roam vast wildernesses.

Across the country, some zoos are bowing to animal-rights groups' pressure by shipping their elephants to sanctuaries, while others are building larger enclosures to ward off criticism about the animals' living conditions.

Animal-rights groups have intensely scrutinized zoos where elephants live in cramped circumstances or without companionship for more than a decade. Since 2000 some zoos, including Chicago, Detroit and San Francisco, have given up elephants entirely, conceding the enormous animals need too much space and money to maintain. Other zoos are following suit, either moving their elephants or not planning to replace aging animals after they die.

In Alaska, publicity about Maggie, the lone elephant at Anchorage's zoo, prompted the board to agree earlier this year to send her south. Seven zoos in warmer climates are vying for the 25-year-old elephant.

But officials at the Sedgwick County Zoo in Wichita, Kan. are planning a new elephant space for 2009 that will give Stephanie and Cynda, their current female African elephants, and five new elephants 3.6 acres to roam. In Oakland, Calif., four African elephants wander more than five acres of elephant habitat, the result of a $100,000 expansion.

After years of lobbying by animal-rights activists, 46-year-old Ruby of the Los Angeles Zoo, retired to the Performing Animal Welfare Society's elephant sanctuary in San Andreas, Calif. But the zoo's other elephants will soon enjoy a new $39 million, six-acre habitat.

Such changes don't satisfy many animal-rights activists, who argue elephants belong in the wild or in much bigger sanctuaries.

"The zoos are knowingly acting irresponsibly in keeping the elephants on surfaces and spaces totally inadequate for them because they don't want to lose their biggest attractions," said Elliot M. Katz, President of In Defense of Animals.

In Seattle, elephant welfare jumped into the headlines after the sudden death of Hansa, a six-year-old Asian elephant who died of a previously unknown type of herpes virus infection.

Zookeepers expected criticism from animal-rights groups, which they see as a thinly veiled campaign to eventually close zoos entirely by attacking their most popular and charismatic attractions.

"The people who really care about animals are in zoos," said Seattle's Woodland Park Zoo Deputy Director Bruce Bohmke. "And we are constantly challenged to find a way to make zoos better."

So, how much space do elephants need?

Most zoo directors maintain it's not the size of the exhibit but the quality of care and the use of space that matters. Some zoo officials use Woodland Park Zoo as a positive example because they say its layout maximizes an acre of land for three elephants.

"We still get visitors who can't find the elephants," Bohmke said. "It's a very long acre."

The Association of Zoos and Aquariums requires at least 400 square feet of indoor space and 1,800 square feet, about the size of six parking spaces, to house an elephant.

"We felt and we continue to feel that space is very arbitrary," Mike Keele, deputy director of the Oregon Zoo and chair of the association's elephant advisory group. "What is really important is the animal's condition and if they are behaving normally."

Animal-rights activists argue the creatures need far more space. The Elephant Sanctuary in Tennessee has 2,700 acres for 23 elephants and the Performing Animal Welfare Society's California sanctuary has 75 acres for eight elephants. There are about 43,560 square feet in an acre.

Elephants in the wild can travel dozens of miles in a day, but zoos cite studies showing that they don't need to roam as much if they have enough food, water and companionship.

"In the wild they are trying to find food, they're foraging. You do get the trade-off in zoos of not needing to forage, so then do they really need that much space?" said Ted Friend, an animal science professor at Texas A&M University who focuses on determining optimum living environments for animals.

Many animal-rights organizations argue minimal exercise and hard concrete floors cause arthritis and gruesome foot problems. According to an In Defense of Animals study of Association of Zoos and Aquarium member medical records, more than 60 percent of elephants in zoos suffer from foot problems.

Zoo officials contend those problems are the lingering results of zoo practices from decades ago.

"Fifty years ago we didn't know what concrete surfaces would do to an elephant's feet," Bohmke said. "It's a constant learning process."

An association survey of its own member zoos shows the overall health of the 284 elephants is 8.74 on a 10-point scale.

Animal-rights activists also argue zoo-type captivity results in premature death for animals that can live as long as 70 years in the wild. A study of captive elephants published in Zoo Biology reported the life expectancy of North American Asian elephants at 35.9 years and 33 years for African elephants in zoos.

Fighting with animal rights activists about the care of elephants is as old as the Association of Zoos and Aquariums itself, which started in 1971, Keele said.

"We got those criticisms and we'll get criticism again. We still look at it. We don't ignore it, we can't afford to," Keele said.

Zoos argue letting zoo visitors see elephants up close is the most effective way to get people to care about conservation and ultimately contributes to saving natural elephant habitats in Africa and Asia.

Sanctuaries, meanwhile, are usually closed to the public and many don't plan to breed elephants.

Some zoos are considering purchasing large amounts of space to house larger elephant herds.

In 2006, the Pittsburgh Zoo announced it would buy 700 acres for a conservation center focused on breeding elephants. Another group of 10 zoos is deciding between three sites for an elephant research and breeding center.

On the Net:

Association of Zoos and Aquariums: http://www.aza.org/

In Defense of Animals: http://www.idausa.org/

The Elephant Sanctuary: http://www.elephants.com/

Performing Animal Welfare Society: http://www.pawsweb.org/

Zoos that have eliminated elephant exhibits since 2000:

Gladys Porter Zoo, Brownsville, Texas

Lincoln Park Zoo, Chicago

Detroit Zoo, Detroit

San Francisco Zoo, San Francisco

Chehaw Wild Animal Park, Albany, Ga.

Henry Vilas Zoo, Madison, Wis.

Zoos eliminating elephant exhibits:

Lion County Safari, Loxahatchee, Fla., and Philadelphia Zoo - Looking for a new home for its two remaining elephants.

Central Florida Zoological Park, Lake Monroe, Fla. - Will probably not replace two female elephants after they die.

Bronx Zoo, New York and Santa Barbara Zoo, Calif. - Will both maintain two elephants until one dies and then send remaining elephant to another zoo

Zoos improving elephant exhibits:

Since 2005, 40 zoos have committed to expanding their elephant exhibits, and more than 20 have upgraded or rebuilt their exhibits in the past 10 years. Some major projects:

Los Angeles Zoo, Los Angeles - Building a $39 million, six-acre Asian elephant exhibit scheduled to open in late 2009.

Sedgwick County Zoo, Wichita, Kan - Plans a new elephant exhibit for 2009 with more than three acres of outdoor space.

San Diego Zoo, San Diego - Plans to break ground on a $23 million elephant house this year.

National Elephant Center - Little Rock Zoo, St. Louis Zoo, Columbus Zoo and Aquarium, Indianapolis Zoo, Birmingham Zoo, Fort Worth Zoo, Denver Zoo, and Woodland Park Zoo in Seattle, Sedgwick County Zoo, Disney Animal Kingdom - looking at buying 100 acres for a research, breeding and sanctuary for elephants.

Pittsburgh Zoo and Aquarium, Pittsburgh, Penn. - Developing a 724-acre International Conservation Center to accommodate 20 elephants for breeding and management programs.

Denver Zoo, Denver - Planning a $52 million, 10-acre exhibit including five habitat areas for six to eight adult elephants

National Zoo, Washington, D.C. - Announced plans for a $60 million exhibit with at least four acres of outdoor and indoor space for eight to 10 elephants.