Inside the small-animal treatment room at the Denver Zoo’s new $24 million hospital, a veterinarian, veterinary technician, and keeper are finding out what it’s like to be the ones on display: About four feet above them, visitors ogle the trio at work removing keratin buildup from a diminutive African penguin’s beak. Children press their hands and faces against the giant pane of glass that separates the public viewing area from the room, which is lined with stainless steel cabinets and high-tech medical equipment. A mic’d-up interpreter explains that Maddy, the flightless bird lying on the procedure table below, periodically needs to have her beak trimmed. “It’s made of the same thing as your fingernails,” she says.

The Helen and Arthur E. Johnson Animal Hospital, a 22,000-square-foot clinic that puts the Denver Zoo among the world’s foremost zoological health care sites, officially opened in late May. On this day, the crowd—guests allowed in for a test run a few weeks earlier—is gathered around the action in the first of three rooms the public can now peer into from a wide, covered corridor. The second is a treatment room for large animals, such as camels and lions, and the third is a surgical suite. Above the windows, flat-screens show live feeds from cameras inside, one of which the interpreter can manipulate to zoom in on areas of interest as procedures are underway. It’s also her job to narrate and answer visitors’ questions, sometimes with the help of the veterinarian, who has a line to the interpreter’s earpiece as well as the ability to talk directly to guests through the sound system.

The zoo’s state-of-the-art, $24 million hospital. Photo courtesy of Denver Zoo

The setup makes Denver’s zoo one of just a handful in the country to let visitors watch its medical staff work on everything from foot-long aye-ayes to 900-pound zebras. When Denverites approved a bond in 2017 to help fund a replacement for the old hospital—half the size of the new one and originally constructed in 1969—the zoo knew that it wanted to build a facility that would allow its doctors to provide levels of care well above the industry standard. “Our veterinarians are four of only about 230 or 240 individuals on the entire planet who are certified in zoo medicine,” says Brian Aucone, the zoo’s senior vice president for animal sciences. “We matched the building to their expertise.”

If the welfare of the animals in its care were the zoo’s only concern, behind-the-scenes improvements might have been enough. But as it has for much of its 125-year history, the Denver Zoo was also thinking about its charge to entertain and educate its other constituents: the humans who visit.

The details of how, exactly, Billy Bryan ended up living in a cage in City Park in 1896 vary depending on the source, but most point to the black bear and the crowds he drew as the Denver Zoo’s origin story. In those early days, the zoo was little more than a random menagerie of animals, fed and cared for primarily by park staff. “The reality was that they didn’t have a whole lot of experience caring for the animals or understanding what their needs were,” Aucone says. “Putting a bear in a steel cage and stocking it with whatever food you could come up with was OK, because that’s what people knew.”

By the early 20th century, cages were still the norm across the country. So when the zoo debuted Bear Mountain in 1918—a replica of a mountainside near Morrison, separated from guests by a moat in which the bears could frolic—it was a big deal. “That was the first attempt in the United States, and one of the first in the world, to look at a naturalistic design and think about the needs of the animal and what the guests would be looking at as well,” Aucone says. “That got the bars out of the way, and it also gave it a sense of place. As a guest, you come in and understand, ‘Oh, this is similar to the habitat an animal might live in.’”

That paradigm of improving animal welfare in tandem with the guest experience has guided the zoo ever since. Benson Predator Ridge, which opened in 2004, rotates African lions and spotted hyenas through three different enclosures; the animals leave behind fresh, stimulating scents for one another, and visitors have the ability to see both species up close in the smaller, glass-walled section. Four years ago, an exhibit called the Edge erected 12-foot-high walkways to help the zoo’s two Amur tigers view their surroundings as they would as predators in the wild, a thrilling, if unnerving, experience for humans below. And a new African penguin habitat, expected to be finished next month, will give Maddy and her pals more distance and depth to swim and dive—while zoo guests watch through 40 feet of glass below the water’s surface. “Animal care and the guest experience really are the two pillars,” says George Pond, the Denver Zoo’s senior vice president for planning and design. “We can’t give up either one. It’s the challenge of zoo design and execution—to be able to hold your head up and say you met those challenges.”

Judging by the fascination of the group watching Maddy’s beak trim, the zoo has found another fruitful intersection of human entertainment and animal well-being with the new hospital. In addition to the interactive viewing area, the Denver Zoo constructed the facility’s hallways and rooms to accommodate all but the zoo’s most gigantic residents (elephants and giraffes, for example, still receive treatment in their habitats) and invested in a nearly three-foot-diameter CT scanner, one of the largest on the market. Before, when Dr. Scott Larsen, the Denver Zoo’s vice president for animal health, suspected there might be a tumor or a bone fracture inside a gorilla, he’d have to sedate the 350-pound ape and coordinate with a local partner, such as National Jewish Health, to transport the animal to a human facility. “It’s an incredible diagnostic tool,” Larsen says of the device, whose images can establish baselines in healthy animals and confirm problems in sick ones. “We used to do maybe seven or eight scans a year; now we’re doing two or three a week.”

Charlotte, a two-toed sloth, undergoes an exam. Photo by Hyoung Chang/MediaNews Group/the Denver Post via Getty Images

Larsen hopes visitors will come back often in the hopes of catching a particularly exciting operation; he estimates there will only be something actively happening about a quarter of the time the zoo is open (and because of the emergent nature of medicine, there’s no public schedule of procedures). The interpreter can always pull up past footage, though, meaning your sloth-obsessed 12-year-old can ask to see, say, an ultrasound of a pregnant female—and perhaps deepen her connection to animals at the zoo and beyond. “Of course, we want people to enjoy themselves, but it’s not just about coming here to have fun,” Denver Zoo director of communications Jake Kubié says. “The better we design the zoo and the better time people have, the closer they’re able to get to the animals, hopefully that will inspire people to learn more and act more on behalf of wildlife.”

At the hospital’s ribbon-cutting ceremony in late May, Mayor Michael Hancock reminded the audience of a coming opportunity to do just that by approving the $400 million municipal bond that will be on Denverites’ ballots in November. Along with the city’s other cultural institutions, the zoo hopes to get some of that money, which it desperately needs after the pandemic. In 2020, earned revenue plummeted by 40 percent compared with 2019, but operating costs—including some 3,300 literal mouths to feed—sunk only 18 percent. “Nothing is static here,” Kubié says. “A lot of it is advancement, but some is just keeping up with maintenance on a 125-year-old campus.”

More accessible pathways and roof repairs, for which the Denver Zoo has requested funding from the 2021 bond, may not be as exciting as a marquee attraction like the animal hospital. They’re just as important, though, to ensure the zoo survives to fulfill its mission for another 125 years. “We’re looking out for the best for our guests and the best for the animals,” Aucone says, “and finding where those meet.”

(Read More: Inside the Denver Zoo’s Effort to Save Colorado’s Rare Boreal Toad)