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A female Mexican gray wolf in Saguaro National Park.

The Arizona Game and Fish Department recently took steps to increase genetic diversity in the Mexican gray wolf population.

Recovery of the Mexican wolf has been slow, in part because of the illegal shooting of wolves.

Another problem is that there are not many animals left in the gene pool.

The department announced recently that it has placed 11 captive-born wolves into wild dens in Arizona and New Mexico.

The agency has had some success with the program, now in its seventh year, in which the wild parents care for the captive-born pups.

But conservationists say that only four of them have bred since the program began.

→ A young wolf traveled hundreds of miles to build a life in Arizona. Then someone shot him dead