Officials of a suburban Chicago zoo say the birth of a litter of Mexican gray wolves marks a major milestone in the conservation of an endangered species.
The two pups emerged Tuesday from their den at the Brookfield Zoo's wolf habitat and romped through their lush woodland enclosure. They were born in May.
Chicago Zoological Society vice president Bill Zeigler says the birth of the litter is part of a successful international program for the recovery of Mexican gray wolves in North America.
Because the puppies are candidates for future release to the wild when they are adults, they will have minimal contact with humans.
Zoo officials say the puppies will remain at Brookfield at least until a second litter is born next year to parents Zana and Flint.