The last of a pack of Mexican gray wolves at a Michigan zoo was euthanized on Wednesday due to advancing old age and deteriorating health issues.
“Phoenix,” part of a pack of eight wolves born at Binder Park Zoo near Kalamazoo in 2002, was the last of the wolves to die. He was 14 years old while the average age of death for a Mexican gray wolf is 11.
Of the pack of wolf pups born with “Phoenix,” four females were relocated to live at other facilities, and the rest, all males, spent their lives at the Binder Park Zoo.
Mexican gray wolves are the most highly endangered subspecies of gray wolf on the planet. Once a ubiquitous sight in the Southwest United States and Northern Mexico, they were nearly eradicated by ranchers who feared they were a threat to cattle. There are only about 350 left in the world and only 50 living in the wild.
Conservation efforts and breeding in captivity, however, have helped maintain and even slightly grow the population in recent years.
While the Mexican gray wolf was added to the federal endangered species list in 1976, it wasn't until 1998 that the first captive-bred wolves were released into the wild.
The reintroduction effort has been hampered by politics, illegal killings and other factors. Disputes over management of the program have spurred numerous legal actions by environmentalists who want more wolves to be released and by ranchers concerned about their livelihoods and safety in rural communities.
Despite the increase in wolf numbers, federal wildlife officials are still concerned about ensuring genetic diversity. Inbreeding can cause a number of problems, including low survivability among pups.
"While overall numbers are important, this is somewhat worrisome," said Michael Robinson of the Center for Biological Diversity. "This is a narrow base for the future. Breeding pairs give us insight into the potential for growth of the population."