Nova, a 25-pound clouded leopard, was missing.
Golf carts rolled down empty pedestrian walkways as helicopters and drones hovered overhead. Zoo workers and Dallas police officers used binoculars to comb the treetops across the 106-acre zoo.
On Friday morning, zoologists found a tear in the mesh in the zoo’s two-story clouded leopard enclosure. Investigating further, they found Luna, a 3- or 4-year-old clouded leopard, safely in her habitat. But Nova, her sister, was gone.
The zoo issued a Code Blue, meaning a “nondangerous animal” was missing from its enclosure, Harrison Edell, the zoo’s executive vice president for animal care and conservation, told reporters on Friday.
Mr. Edell said the Dallas police responded, bringing drones with “infrared capabilities,” which helped zoo workers to scan the treetops.
He emphasized that Nova posed no danger to humans and most likely had not left the zoo property.
Because clouded leopards “are designed for life in the trees,” she had probably climbed one and would “stay out of our way, hunt some squirrels and try not to be noticed,” he said.
Mr. Edell said members of the zoo’s staff believed that both clouded leopards were still in their enclosure at 1 a.m. Friday. There was hope that the timing of Nova’s escape, in winter when the trees are bare, would make her easier to spot, he said.
Luna and Nova arrived at the Dallas Zoo from the Houston Zoo in September 2021, according to a post on the Dallas Zoo’s Instagram account.
Clouded leopards are becoming more common at zoos across the country because of their inclusion in a species-survival program, said Paul Frandsen, a professor of plant and wildlife sciences at Brigham Young University.
“The females are a little bit nicer than the males,” Dr. Frandsen said. “But I think, like any wild animal, that they’re not totally domesticated. It’s not like a little cat.”
Clouded leopards are native to Southeast Asia and are listed as endangered by the U.S. Fish and Wildlife Service. The name refers to the markings on the leopards’ fur, which can look like clouds, but Dr. Frandsen said he likes to think of the name as a nod to their treetop dwellings.
While Mr. Edell said officials did not believe Nova had left the Dallas Zoo, he encouraged anyone who sees her to contact the zoo by calling its main phone number or by writing the zoo by email or through its social media accounts.
While Nova is not considered dangerous, he cautioned people not to approach her.
“Even though this is a small cat — she’s only 25 pounds; this is not a tiger or a lion — she’s still got a full complement of claws and teeth,” he said.
Dr. Frandsen also stressed that people should keep their distance.
“When they’re stressed, then that can also be a little bit dangerous, but it’s not like a lion,” he said. “So I think it would be probably not smart for a human to go up and approach a clouded leopard, even if it’s a captive-bred individual.”