Ivan the polar bear has been having relationship problems recently.

The strapping 300-kg, 10-year-old lives at Asahiyama Zoo, a municipal facility on a wooded hillside in the city of Asahikawa, central Hokkaido. The zoo is Japan’s most northerly, and 15 years ago it was near bankruptcy. Today, crowds come from as far away as Tokyo, Seoul and Beijing to see the animals — and they often make a beeline for the polar bear house.

Enthralled, they watch Ivan swim gracefully in his pool and devour buckets of horse meat, hokke mackerel and the occasional head of Chinese cabbage. Parents snap pictures. Small children often recoil in shock when he approaches them just centimeters away on the other side of acrylic windows, his big black eyes staring right at them and his every nose-wriggle and translucent hair clearly visible.

Without doubt, Ivan — or “Eewan” as he is known to countless Japanese fans — is a national and international star.

Yet Ivan, who was born at a zoo in Russia, also belongs to a species that is increasingly threatened by global warming, and that means the (human) pressure is on for him to produce offspring. Asahiyama succeeded at the notoriously difficult task of captive polar bear breeding back in 1976, becoming the first zoo in Japan to do so. But when Ivan was paired with 16-year-old Lulu last year, matters did not proceed smoothly.

“He’s just too nice. He couldn’t even lift his head around Lulu,” said polar bear keeper Tomohiro Sahashi, 26, who serves as the hulking wallflower’s main romantic coach.

Like all the keepers at Asahiyama Zoo, Sahashi was just an ordinary city employee when he was posted there four years ago. He hadn’t attended college and says that at first he wasn’t even interested in animals. But innovation is encouraged at Asahiyama, and inspired by that Sahashi boldly set out to tackle the problem.

“I did some research about polar bear mating in the wild. In nature, they’re not all lovey-dovey,” he said. Rather, wild pairs come together only for a period of about one week a year — and though the males seek a mate every year, the females only breed every three years.

In contrast, Ivan and Lulu were chums who had been living in the same pen long term. Sahashi decided to separate them, then reunite them temporarily to approximate what might happen in nature. It worked.

“Ivan acted totally different,” he said. Soon the pair was observed mating, although Lulu did not become pregnant, and, starting this spring, Ivan has been paired with a different mate.

That knack for getting animals to act more like they do in nature is something a lot of the keepers at Asahiyama share — and it certainly accounts in no small part for the zoo’s popularity. Where Western zoos often focus on recreating wild habitats (such as indoor jungles and urban savannahs), and aquariums sometimes resort to shows and tricks, Asahiyama simply lets visitors watch as animals go about their ordinary business — whether mating, swimming, climbing or raising their young.

According to zoo director Gen Bando, 49, that’s not quite as easy as it sounds.

“A penguin doesn’t say to itself, ‘I think I’ll go for a swim today.’ If they don’t need to swim, they stop swimming. It’s a question of how to awaken those sleeping abilities by creating an environment where they will naturally happen,” said Bando as he sat in his office on a typically crowded recent morning at the zoo.

The technical term for this is “behavioral enrichment,” and it is Asahiyama Zoo’s core philosophy. It involves both the design of the enclosures (for example, installing hammocks, logs or climbing structures) and the methods the keepers use when caring for the animals (such as hiding food around their living spaces) — but it doesn’t necessarily mean replicating natural-looking habitats.

Indeed, at Asahiyama Zoo, animals’ environments are more likely to be made of concrete, steel and plastic than trees and dirt — and they always include a front-row view for visitors. Yet from Ivan’s diving pool to a walk-through aviary and a towering rope bridge where orangutans swing high over visitors’ heads, these signature behavioral enrichment exhibits keep the animals active and the tour buses coming.

While behavioral enrichment is gaining popularity across Japan and beyond, however, some question just how far the idea can go.

“Three of the biggest things that animals need to do in the wild — get food, protect themselves from predators, and find mates — all that’s taken care of,” said Jeffrey Hyson, an assistant professor of history at Saint Joseph’s University in Philadelphia, Pennsylvania, who is currently writing a book on the cultural history of zoos.

“Behavioral enrichment is a really powerful tool to improve animal welfare and get visitors interested. People love seeing an animal search through logs or blocks of ice for its food. Whether that actually keeps the animal more ‘itself’ is a much more debatable premise,” he said.

Asahiyama Zoo is one of Japan’s best arguments in favor of that premise, but the question remains valid. Can animals really lead animal-like lives within the profoundly unnatural environment of a zoo?

Asahiyama Zoo hasn’t always been so focused on behavioral enrichment. Back when it opened in 1967, it followed the lead of other Japanese zoos and displayed its animals much like an art museum might present sculptures: as caged objects, not living beings. Amusement-park rides shared the zoo grounds, and the complex enjoyed moderate popularity with locals.

By the mid ’80s, however, the zoo’s facilities were aging and visitor numbers were declining steadily. The same was true at zoos throughout Japan. Then, in 1994, a gorilla and a ring-tailed lemur at Asahiyama died from the parasitic disease Echinococcus multilocularis, and the zoo closed temporarily. When it reopened the following spring, the public failed to return.

Meanwhile, changes were in motion that would eventually get Asahiyama Zoo back on its feet. In 1986 the keepers, who had until then shied away from talking to the public, started presenting “one-point guides” about the animals. The next year the zoo started opening at night a few times each summer. And soon after, keepers began making handwritten informational signs to replace the standard placards — a feature that remains extremely popular with visitors today.

Building on these low-budget successes, keepers started to dream about more drastic changes. That exciting phase of the zoo’s life was dramatically recreated in the 2009 hit film directed by Masahiko Tsugawa, “Asahiyama Dobutsuen Monogatari: Pengin ga Sora wo Tobu” (Penguins in the Sky — Asahiyama Zoo), which zoo spokesperson Takehiro Nakata says bears a fair resemblance to reality.

Bando came to Asahiyama in 1986, just as these changes began. Today he is a tanned, muscular man who walks the grounds with unassuming confidence, stopped now and then by a mother who has seen him on TV or a longtime fan of orangutans wanting to ask him what they are really like as individuals. Back then, he was a 25-year-old animal lover fresh out of veterinary school. When employees gathered to talk about how they’d like to improve the exhibits, Bando thought of the seals, one of the zoo’s most underrated species.

“There were these animal ‘booms’ — a panda boom, a koala boom. I came to the zoo during an otter boom, but we didn’t have an otter,” he recalled. “People would be looking at the seals and say, ‘Don’t you have an otter?’ Everyone was bored with seals.

“I really regretted that, but zoos created that value-set themselves, by the way they handled the animals. I thought, one day I want to show people how great these guys are. The basic truth in any zoo is that the animals live from birth to death confined in a pen. But within that, I wanted to create an environment where they could live seal-like lives, move and react like seals,” he said.

In particular, he noticed that in nature seals often dive straight down — “like a stone dropping through water” — and he wanted to build a pool where they could do that in captivity.

That chance finally came in 2004. Ten years earlier, a new mayor had been elected in Asahikawa, and unlike his predecessor, he was in favor of supporting the zoo. After persistent lobbying by Masao Kosuge, director at the time, the zoo was awarded a remodeling budget to mark its 30th anniversary. That attracted more visitors, generated more funds and kicked off the ongoing construction of new facilities based on the principle of behavioral enrichment. The petting zoo opened in 1997, followed by new facilities for birds and “beasts of prey.” In 2000, a penguin house was built, featuring an underwater tunnel that visitors could walk through as penguins “flew” through the water overhead. This soon became an extremely popular exhibit, and the film “Penguins in the Sky” made it emblematic of the whole zoo.

In 1999 the zoo stayed open in the winter season for the first time, and finally, in 2004, Bando’s dream of a new seal house became reality. It features deep pools, outside areas and multiple viewing rooms — but the heart of the display is a transparent vertical tube of water that the seals plunge through like pudgy torpedoes as visitors stand and watch.

Today, despite Asahiyama’s relatively remote location and modest scale (150,000 sq. meters, 743 animals of 130 species, and about 50 permanent employees), visitor numbers rival those at Tokyo’s Ueno Zoo. Close to 2.5 million people visited in 2009, and on busy days a 15-minute wait to get into the seal house is not unusual.

Success has allowed the zoo to become financially independent from the city, relying instead on ticket revenue, donations and concession rentals to cover its ¥14.5 billion annual budget. In contrast, according to the Japanese Association of Zoos and Aquariums (JAZA), most Japanese zoos receive about 70 percent of their funding from taxes. Cities throughout Japan are taking note, said JAZA’s Kenichi Kitamura.

“With Asahiyama, local governments realized what a useful tool zoos can be (for tourism and education). Most of the big zoos are now starting to put together renewal plans. They’re copying (Asahiyama’s) display style and getting more proactive in general,” said Kitamura.

Some visitors and outside critics, however, question whether even a zoo that claims to focus on behavioral enrichment can really offer its captive inhabitants a humane life.

“I’m not sure I approve of zoos,” said Chris Wilson, a 45-year-old software company employee who visited Asahiyama with his wife and 14-month-old son over Golden Week in May.

“It doesn’t seem very natural. Some animals were pacing back and forth, and that’s a sign of stress,” added Wilson, who is originally from Britain but now lives in Yokohama.

Many zoos worldwide have, however, worked hard to redefine themselves over recent decades in response to concerns such as those Wilson expressed. Gone are the days when they were simply places to have fun looking at animals. Some have built larger, more naturalistic enclosures. And with species extinction and habitat destruction forming an unrelenting backdrop, most now say conservation is their top priority.

In the United States, both the Department of Agriculture and the nonprofit Association of Zoos and Aquariums (AZA) make sure zoos live up to those promises through licensing and accreditation programs — but no such system exists in Japan, and conditions remain less than ideal at some smaller zoos.

JAZA’s Kitamura said that independent oversight is complicated in part because about 70 out of 90 of the country’s zoos are run by city or prefectural governments. He added that public management brings other problems as well, including the fact that employees are often transferred in and out of zoos, and sometimes even directors have little experience in the field.

Born Free, an international charity organization based in England, campaigns for better zoo oversight worldwide, but also questions the validity of any zoo.

“We believe wild animals belong in the wild,” said David Turner, senior operations officer of Born Free’s Zoo Check program. While 82 percent of the animals at Asahiyama were born in captivity, Turner pointed out that they are genetically identical to individuals born in the wild and therefore no more suited to a life in captivity.

Although many zoos (including Asahiyama) cite the value of their extensive research and breeding programs, instances of animals bred at zoos actually being reintroduced in the wild are rare. Consequently, Turner claimed that the money spent on breeding programs would be better put toward habitat restoration and in-situ conservation. As for education, he said zoos present an unnatural image of animals isolated from their natural environment and social conditions.

Bando sees the conservation and educational value of his institution in a different light.

“All sorts of people visit a zoo. They come on dates, or with their family — ordinary people without a particularly high level of awareness. That’s exactly why a zoo has the potential to really change people,” he said.

Asahiyama’s strategy for doing so is both emotional and intellectual. Posters, presentations and even entire animal exhibits consistently emphasize the human causes behind habitat loss and species extinction. For instance, one recently constructed exhibit juxtaposes wolves, hunted to extinction in Hokkaido a century ago, with the deer that have exploded out of control there as a result.

Other displays inform visitors about the zoo’s on-the-ground conservation efforts (see the related article on a project to build a wildlife rescue center in Borneo) or highlight the effects of global warming.

At seal feeding time, for instance, a keeper giving a presentation urged visitors to ride their bikes more often to reduce carbon-dioxide emissions — though the solemnity of his comments was somewhat undermined by a hungry seal that persistently pawed his leg in hope of more fish.

Nonetheless, Bando admits that few people come to the zoo to learn about these problems.

“We can’t force things on them. The zoo should be enjoyable — if we don’t get people to realize how wonderful the animals are, we lose. The most important thing is for that feeling to stay with people,” he said.

For Bando, of course, that means highlighting the animals’ natural abilities and characters through behavioral enrichment. Yet truly embracing that approach also means accepting a surprising degree of risk within the zoo.

For instance, chimpanzees are allowed to work out conflicts among themselves with as little human interference as possible, even though that means they sometimes bite each other. Many of the climbing structures are high enough that if an animal were to fall, it would die. And in a tragic accident last April, a 6-year-old orangutan did die when her neck became caught in a rope in her sleeping area.

“If you put an animal in a cage with nothing in it, there won’t be any accidents. But their character as an animal also disappears,” said Bando. He pointed to a high rope bridge in the orangutan enclosure as an example.

“Until last year, the mother would always carry the baby across. Around the end of the year, she started making the baby practice on its own, leaving it up there. It would really cry, but the mother would urge it on, and this April 29 it crossed by itself. Because that sort of environment is available, the relationship between mother and baby becomes stronger,” he said.

Staff management practices follow a similar hands-off philosophy. The director sets broad policies (absolutely no animal shows, for example), but keepers plan their own feeding-time presentations, determine the text of the posters, and continuously devise new ways to enhance the animals’ living environments and feeding regimes.

“Within the basic framework, employees can experiment freely. If everything is predecided, right or wrong, it’s boring,” said Bando. What he said next could sum up his philosophy as a zookeeper as well as a manager.

“I want to know how much gray we can have,” he said. Then he strode off toward the monkey house, walkie-talkie buzzing quietly, the sleeves of his gray-green uniform pushed up to the elbows and a penguin-print towel tucked into his waistband.

Admission to Asahiyama Zoo is ¥800 for those of high school age or above. Entrance is free for children. During the summer season (from April 29 to Oct. 17), it is open every day from 9:30 a.m. to 5:15 p.m.; in the winter season (from Nov. 11 to April 7), it is open from 10:30 a.m. to 3:30 p.m. The Night Zoo (from Aug. 11-15) is open till 9 p.m. Most display details are in Japanese only; maps are available in English.