Colorado wildlife officials last weekend spotted the state's first known litter of gray wolf pups since the 1940s, a wire service is reporting.

Gov. Jared Polis said a state biologist and district wildilfe manager each observed the litter with at least three pups with their parents, according to The Associated Press.

Centennial State voters last year narrowly approved a ballot measure requiring the state to reintroduce the animal on public lands by the end of 2023, the AP notes.

Gray wolves were removed from the federal endangered species list earlier this year but are still protected in Colorado.