New York's Wolf Conservation Center has some new residents - eight pups of the endangered Mexican gray wolf species, which join the 16 already living in a reserve dedicated to preserving these canines from extinction.

The newborns include five males and three females, all in perfect health, the center said on its Web site.

The litter is a great contribution to the survival of this species, one of the most endangered on the planet.

Only about 400 specimens of Mexican gray wolf survive, of which 24 are now at this reserve in South Salem, New York state.

The populations of these animals, endemic to central and northern Mexico and which once roamed the southwest U.S border states like Texas and Arizona, began to decline in numbers during the mid-19th century when they were widely hunted down to keep them from killing cattle.

By the mid-20th century they had been exterminated in U.S. territory while wolf packs in Mexico where considerably depleted.

Things got worse for the Mexican gray wolf from then on and by 1976 it was considered in danger of extinction, the motivation for its reintroduction into Arizona and New Mexico as part of an intense campaign to save it.

Its litters typically consist of between four and six pups born after a 63-day gestation period.

Besides Mexican gray wolves, the conservation center in the town of South Salem in Westchester County, New York, is home to six specimens of red wolf, a species of which only 300 exist in the world.