The three big cats delighted visitors to the Nebraska zoo for years - pouncing on pumpkins during Halloween, preening for pictures and lounging on rocks in their enclosure.
The Lincoln Children's Zoo has described the snow leopards as silly, bubbly and handsome. They were one of the zoo's main attractions, delivering a dose of mountain majesty to the Great Plains.
But on Friday, the zoo announced that the leopards - Everest, Makalu and Ranney - had died of complications from covid-19, about one month after the animals had tested positive for the coronavirus. While scientists are still studying the effects of the virus on animals, members of several species have been infected and died in zoos around the world. Snow leopards are considered vulnerable to extinction, with just a few thousand estimated to be living in the wild.
The Lincoln cats "were beloved by our entire community inside and outside of the zoo," the zoo said in a statement. "This loss is truly heartbreaking, and we are all grieving together."
Two Sumatran tigers, Axl and Kumar, were also infected, but the zoo said Friday that they "have made a seemingly full recovery from their illness."
The zoo will remain open to the public. The park said it has strict coronavirus protocols in place for animal areas, including mask use for staffers working inside. An investigation did not determine the cause of the outbreak, it said.
It is possible for humans to infect cats with the coronavirus and for cats to pass it on to other cats, according to the Cornell Feline Health Center. However, the Cornell center said, there is not yet evidence that cats can infect people. The Food and Drug Administration classifies the risk for animal-to-people spread as low.
Last month, the park said its animal keepers had "observed symptoms consistent with the virus in felids," which can include coughing, fatigue and loss of appetite. They collected nose swabs and fecal samples, and the cats tested positive soon after, the zoo's first and only cases.
In a statement in October, the zoo said the infected animals were being treated with steroids and antibiotics, but it did not say whether they had been vaccinated. Zoetis, a former Pfizer subsidiary based in New Jersey, has provided an animal-specific coronavirus vaccine to zoos across the country. The Lincoln Children's Zoo did not immediately respond to an interview request.
The three snow leopards' exploits have been documented in dozens of the zoo's social media posts over the years. A video from last year shows Everest executing a backflip onto a pumpkin, and a 2015 post celebrating his recent arrival noted that he "quickly became a guest favorite with his playful and energetic personality." Ranney, meanwhile, had a penchant for posing for photos belly-up and snoozing on stones.
Since April 2020, when a tiger tested positive for the coronavirus at the Bronx Zoo, dozens of animals in captivity in the United States have become infected. This month, the Denver Zoo reported the world's first two coronavirus cases in hyenas, and the St. Louis Zoo found eight positive cases among its big cats, including in two snow leopards.
Snow leopards have also been infected at the Louisville Zoo and the San Diego Zoo, where 9-year-old Ramil began having a cough and a runny nose in July. Abroad, the virus has killed a lion in India and two tiger cubs in Pakistan.
Alex Herman, vice president of veterinary services at the Oakland Zoo in California, where big cats are getting vaccinated, told The Washington Post last month that it is important to get animals the shots to help slow the spread among all species.
"Humans are being devastated around the world. Animals are being devastated by it as well," she said. "It's one health."