U.S. wildlife officials successfully re-introduced wolves to Wyoming and Idaho 20 years ago, and by 1999 wolves had made their way to Oregon, as well.

Environmentalists say wolves keep the ecosystem healthier by killing sick and weak animals and keeping deer and other prey populations under control.

The wolves were spotted earlier this month, on Aug. 9, and are being called the Shasta Pack because they were spotted by surveillance cameras in a forested region near Mount Shasta. Officials knew where to put the cameras after an adult wolf was spotted in the spring.

The pups seen this month are about 4 months old and about 40 pounds, officials said.

California has been waiting for the gray wolves, which the state has listed as an endangered species since June of last year. Because they are protected, it’s illegal to hunt, harm or interact with the wolves.

Not everyone is expected to celebrate the re-emergence of the wolves. Livestock ranchers and hunters may become increasingly concerned as the wolf population grows — but, for now, officials say, it’s enough to celebrate their return.