Only a few weeks ago, wildlife officials in Colorado thought they were tracking two male wolves.

The gray wolves, among only a handful spotted in the state in recent years, had been described as possible hunting partners, roaming around without mates. Not only did one of them turn out to be female, but the pair has now produced a litter of gray wolf pups — the state’s first since the 1940s.

The growing family has taken up residence in Jackson County, which borders Wyoming. Colorado Parks and Wildlife personnel, observing the den site from about two miles away, recorded multiple sightings this month of the two adults with at least three pups, although there could be more since there are usually four to six pups in a wolf litter.

“We welcome this historic den and the new wolf family to Colorado,” Gov. Jared Polis said in a statement last week.

There are likely to be more sightings of the pups, which have not been photographed, as they grow bigger and venture outside the den more often, wildlife officials said.

“We are continuing to actively monitor this den site while exercising extreme caution so as not to inadvertently jeopardize the potential survival of these pups,” Libbie Miller, a state wildlife biologist, said in the statement.

Gray wolves were once found all over North America, but their numbers began to decline significantly in the 19th century as they encountered settlers who viewed them as a threat. By the 1940s, the wolf population in Colorado — as in the rest of the region — had been hunted, trapped and poisoned almost out of existence.

Starting in the 1990s, gray wolves were reintroduced in Yellowstone National Park in Wyoming as well as in central Idaho. A subspecies, the Mexican gray wolf, was also reintroduced in Arizona and New Mexico. But they had rarely been seen in Colorado until 2019, when hunters made the first report in years of multiple wolves traveling together.

Although gray wolves were removed from the federal list of endangered species last year, they are still protected in Colorado, where the penalties for killing a gray wolf can include up to a year in prison, a $100,000 fine and the loss of hunting privileges.

Colorado is also moving to increase its wolf population, and in November became the first state to vote on whether to bring back a native species. Voters narrowly approved a ballot measure that requires the Colorado Parks and Wildlife Commission to devise a plan to reintroduce and manage a gray wolf population on public land in the western part of the state by the end of 2023. The commission was also instructed to set up a fund to compensate ranchers for any livestock the wolves might kill.

Opponents of the ballot measure point to the wolf litter as evidence that the animals don’t need government help to be restored. Mr. Polis and others counter that bringing in other wolves promotes genetic diversity and will provide the pups with a healthy selection of mates once they are grown. The reintroduction plan requires a self-sustaining population and has not been affected by the wolf pup sightings, wildlife officials said.

Dozens of public and private meetings are being planned in the coming months to discuss details of Colorado’s reintroduction plan, which continues to draw opposition from rural residents who say their concerns were drowned out by the urban vote. At least one county has passed a formal resolution against it.

Other states are also embroiled in debates over the status of wolves, one of the most contentious conservation issues in the American West. In April, citing the threat to livestock and other wildlife, the Idaho Senate approved a bill that would allow the state to kill as many as 90 percent of its wolves, which numbered 1,556 at last count.