Stacked along the back of the laboratory’s stainless steel counter were dozens of jars.

There was a golden frog suspended in yellow gel. One bottle was full of zebra eyes. Another held an orangutan heart. And a fourth was something marked “kangaroo 2004,” but it wasn’t clear what it was, maybe tissue.

Kelsy Dickensen focused in on one of the smallest containers, though. Inside was an entire armadillo, gray and scaly and unmoving, curled up and preserved.

“That is the coolest one,” she said, snapping a picture.

(Rick Egan | The Salt Lake Tribune) An armadillo in a jar in the Necropsy room, in the Hogle Zoo Animal Health Center. Saturday, March 16, 2019.

Dickensen and her mom, Suzanne Marelius, took a tour Saturday of Hogle Zoo’s animal hospital — a first-ever behind-the-scenes walk to show visitors what the veterinarians see. Like what they do when a polar bear swallows a glove. Or if a sea lion eats a sock. (Yes, both of those have happened.)

It’s an educational program launched this month with other tours to follow every month after.

“We’ll be going where visitors don’t usually go,” said Angelina Kirkessner, the zoo’s lead education instructor, who created the series and led the inaugural one. “I’ve been trying to get this going for months and months and months.”

The tour Saturday through the health center included a look at the different operating rooms — one with a table that can hold an animal up to 2,000 pounds (which is still not big enough for an elephant) — a peek into the quarantine where new animals are held for 30 days before being put in an exhibit and a discussion in the necropsy room surrounded by the reptile and mammal preserves used for studies. In each one, the two guests, Dickensen and Marelius, oohed and gasped.

One of the jars in the laboratory held feathers and muscles from a starling floating in a red liquid.

“Bird parts?” Dickensen asked, looking up at her mom both puzzled and disgusted.

“Yep, bird parts,” she confirmed with a laugh.

The tours can have up to eight people; this first one, advertised mainly through a Facebook event and costing $40 a person, had only two sign up. The zoo expects more participants in the future as they promote them more and go through different areas and enclosures. (They will post a full schedule on their website hoglezoo.org for tickets and sign-ups.)

The hospital was renovated and tripled in size in 2009, Kirkessner said. Most of the surgical rooms look like a typical doctor’s office with syringes and gauze, cotton balls and tongue suppressors. But they are much bigger and with machinery made for animals the size of a horse — literally.

At the start, Kirkessner led the visitors behind a large wooden gate near the “Rocky Shores” next to where a handful of toddlers were watching otters and seals swim around. The animal center sits behind the enclosures to the north of the zoo along Sunnyside Avenue. Most of the work inside is focused on preventive care and annual checkups with veterinarians taking blood, urine and skin samples for testing. There also is a spot in one corner labeled “poop shoot” for samples of that sort.

Some of the work done here, particularly in the necropsy lab where animals go after they die, can be used to help humans, too. The zoo completed a study in 2015 on how elephants rarely develop cancer, and researchers have used the results to focus on kids with the disease.

“They can help us learn even after they pass away,” Kirkessner said. “We’re still learning.

The bones of two elephant feet are on display there. They are from Dari, the oldest African elephant in North America, who died in 2015 of natural causes at 53 years old. Her joints show arthritis, which scientists have examined here and used to help the other elephants at the zoo and elsewhere.

Dickensen, who works as a surgical tech at LDS Hospital, particularly enjoyed looking at the operating rooms and comparing them to the ones she sees every day. The 27-year-old took photos on her phone throughout the tour.

“I’m showing everyone at work for sure,” she said, wearing a shirt with a red panda on it — her favorite animal.

Marelius, 64, got Dickensen a zoo membership for Christmas and the two have come here often since. This event, they said after, gave them a new perspective on how the animals they love are cared for.

The zoo does about three or four big procedures a year in the hospital, including on snakes and lizards. And it has two full-time vets who know how to take care of every animal on the grounds.

On the screen in the office was an x-ray from a kingfisher bird with its long beak appearing as a sharp white line. In the kitchen was guinea pig food. In the operating room was a dart gun (used sparingly, Kirkessner said).

“Zoo vets have to be the extreme generalists,” she added. “They have to know how to treat a mouse or spider, an elephant or crocodile.”

The tour ended with a look at the four red foxes in quarantine, set to debut at the zoo in a month. They came in when the lone wolf here was sent out in February.

“They’re rescued animals and a native species,” Hansen explained.

Marelius and Dickensen couldn’t look away. “Ah,” they sighed in unison. “They’re beautiful.”