SILVER CITY, N.M.— Thirty conservation organizations today urged wildlife agencies to take science-based actions to protect Mexican gray wolves after a new analysis showed that the endangered species’ genetic diversity declined for the fourth year in a row.

In a letter to the U.S. Fish and Wildlife Service, Arizona Game and Fish Department and New Mexico Department of Game and Fish, the groups requested that government agencies release wolf families because the captive population has 37% more genetic diversity than the wild population.

They also asked state and federal officials to stop removing genetically valuable wolves from the wild and allow Mexican gray wolves to mate with northern gray wolves, as they did for millennia.

“Mexican wolves won’t recover unless agencies restore as much genetic diversity as can be salvaged from what’s already been squandered,” said Michael Robinson, a senior conservation advocate at the Center for Biological Diversity. “Federal and state agencies need to stop killing wolves with important genes and start releasing captive breeding wolves in family packs to give wolves the best chance at survival and recovery.”

The last release of a captive-born, well-bonded pair of wolves with their pups occurred in 2006. Those family packs were overwhelmingly successful. Genetic diversity peaked in 2008 after some of those pups matured and bred.

“Resuming family group releases from Saving Animals From Extinction partners like us is the best way to address this genetic crisis,” said Regan Downey, director of education and advocacy at the Wolf Conservation Center. “The release of the Meridian pack in 2006, whose matriarch flew to the Southwest from our New York facility, provided much-needed diversity and proved once again that captive-born family groups can survive on the wild landscape — they just need the chance. So, let's give it to them.”

Captive-born pups have been taken from their mothers and released into wild wolves’ dens shortly after their springtime births since 2016. But just 24 of 99 pups released through 2023 are known to have survived through the end of their birth year.

“The wild lobo population needs genetic help, and releasing family packs of wolves from captivity is clearly the best way to provide that,” said Chris Smith, wildlife program director for WildEarth Guardians. “Cross-fostering pups makes for heart-warming stories and cute photos, but it is an inadequate strategy to recover Mexican wolves.”

Since April the agencies have removed seven genetically rare wolves by shooting a pregnant female in Arizona and a pup in New Mexico, capturing alive four more wolves in an Arizona pack and killing one of their pups. Snipers are working now to kill the adult son of the slain pregnant Arizona female. In today’s letter, the conservationists asked the agencies to spare remaining genetically valuable wolves.

“The Mexican gray wolf is on the brink because of failed federal and state policies that are actively dismantling lobo recovery,” said Michelle Lute, Ph.D. in wolf conservation and executive director of Wildlife for All. “Science is clear: wolves recover in family packs, not as orphaned pups or isolated individuals. Ensuring full protection for every wolf across their historic range — and halting reckless removals — is the only way this iconic carnivore will survive past our lifetime. Anything less is willful negligence that risks extinction.”

“The U.S. Fish and Wildlife Service needs to really step up for Mexican wolves to ensure that these highly endangered animals recover and thrive — they cannot do that without every effort to maximize genetic diversity in the wild population of wolves,” said Sandy Bahr, director for Sierra Club’s Grand Canyon chapter. “That is why we have for years consistently asked for wolf families with important genetics to be released together and for these agencies to stop removing or killing wolves that contribute to that genetic diversity.”

The conservation groups are also asking the agencies to stop relocating Mexican wolves who travel north of Interstate 40 and northern gray wolves who travel southward. The letter says wolf subspecies always merged at the edges of their ranges and that now, with genetic diversity so low, Mexican wolves desperately need to occasionally mate and raise pups with northern wolves.

“Restricting wolves at I-40 undermines both science and recovery. Genetic resilience depends on natural dispersal, where wolves select mates and establish territories across landscapes as they have for millennia,” said Claire Musser, executive director of the Grand Canyon Wolf Recovery Project. “Wolves must be recognized as active agents in their recovery, not passive subjects of management boundaries.”

The adverse genetic figures that prompted today’s letter were presented at a recent meeting of zoos and other captive-breeding institutions.

“If not addressed, the ever-dropping diversity of the lobo genome will ultimately doom the Mexican gray wolf,” said Mary Katherine Ray, wildlife chair for the Rio Grande chapter of the Sierra Club. “Now that wolf howls have been restored to the canyons and forests of the Southwest, losing them a second time because of human destruction and mismanagement would be shameful and tragic.”

"Mexican gray wolves have the least gene diversity of all North American gray wolf populations. Natural selection in response to changing environmental conditions, also known as evolution, can only work if there are multiple gene forms to select from. Mexican wolves have many gene loci that have only one gene form remaining, which precludes natural selection for that trait. Many of these lost genes could be restored through carefully managed crossbreeding with other gray wolf subspecies, yet the managing agencies refuse to consider this option and refuse to explain why,” said David Parsons, former Mexican gray wolf recovery coordinator for the U.S. Fish and Wildlife Service.

Both captive and wild Mexican wolves stem from just six animals captured decades ago in Mexico and one in Arizona. All others from their unique subspecies are believed to have been killed, largely through an eradication campaign by the U.S government. Mexican wolves suffer from lower reproductive rates, nasal carcinomas and congenitally fused toes, all tell-tale signs of inbreeding. Increasing genetic diversity could help alleviate these problems and give them a fighting chance at true recovery.