April 24, 2017 

Endangered Wolf Center 636-938-5900, Regina Mossotti
Saint Louis Zoo 314-646-4633, 314-646-4639,
Peter Siminski 760-346-5694 ext. 2103

Video and photos available. See sidebar.

Partnership of Government, Institutions Achieved Reproductive Breakthrough for Critically Endangered Species

April 2 marked a historic first in conservation. An endangered Mexican wolf gave birth to a male pup conceived by artificial insemination, using sperm that was preserved by freezing.

"The birth of a pup at the Endangered Wolf Center represents a major breakthrough and is a remarkable example of institutional collaboration between the Saint Louis Zoo, the Endangered Wolf Center (EWC), The Living Desert, the University of California-Davis, the United States Fish and Wildlife Service (FWS) and the Association of Zoos and Aquariums Mexican Wolf Species Survival Plan (SSP)," said Dr. Cheryl Asa, retired Director of the AZA Reproductive Management Center at the Saint Louis Zoo, who for more than 25 years has worked with other national and international organizations to save the Mexican gray wolf.

A decrease in genetic diversity can compromise a population by increasing the incidence of low birth weights, reducing litter sizes and raising the mortality rate of pups. Reproductive technologies, such as frozen semen and artificial insemination, were developed to support gene diversity by allowing reproduction between genetically valuable individuals at different locations and even after natural death of a male.

This pup was born at the EWC using sperm collected by Saint Louis Zoo research and animal health staff in January 2016 from a male Mexican wolf at the EWC and stored at the Saint Louis Zoo's cryopreservation gene bank—one of the world's largest gene banks established specifically for the long-term conservation of an endangered species.

The nonsurgical transcervical intrauterine insemination of the female wolf was performed at the EWC on Jan. 27, 2017 by Dr. Bruce Christensen, DVM, Assistant Professor of Population Health & Reproduction, University of California-Davis with assistance of the Saint Louis Zoo animal health staff.

"This little pup offers new hope," said Virginia Busch, Executive Director of the Endangered Wolf Center. "To succeed in conserving a species, many tools are needed in our proverbial 'toolbox.' Using frozen semen will help maintain the genetic and overall health of the critically endangered Mexican wolf population by allowing scientists to draw from a larger pool of genes—wolves at other institutions and also deceased individuals."

Wolves are keystone species, and as scientists have learned with the reintroduction of wolves in Yellowstone, they are a vital part of keeping the plants and animals in an ecosystem healthy. The Mexican wolf was eliminated from the wild in the United States in the 1970s and from Mexico in the1980s.

Once the captive population grew large enough, FWS launched a reintroduction program in 1998 with the release of 11 Mexican wolves into the wild in Arizona and New Mexico. Now, Mexican wolves are found in Arizona, New Mexico and Mexico. In addition, there are approximately 250 captive wolves in the care of more than 50 institutions both in the United States and Mexico.

"While the captive program has prevented the extinction of the Mexican wolf, with only roughly 130 Mexican wolves in the wild today, we still have a lot of work to do to in order to recover the species," said Peter Siminski, The Living Desert's Director of Conservation, Chair of the SSP and a member of the Mexican Wolf Recovery Team. "We are hopeful the wild populations will benefit from these reproductive technologies, as well."

In 1990, at the request of FWS, the Saint Louis Zoo established a frozen semen bank for the FWS Mexican Wolf Recovery Program and the SSP. Each breeding season, Dr. Asa and Saint Louis Zoo Laboratory Manager Karen Bauman have traveled around the country to collect wolf semen to bank for potential future use.

Today, the frozen zoo—or combined gene bank—located at the Saint Louis Zoo and at the Chapultepec Zoo in Mexico contains genetic materials from over 200 male and female Mexican wolves.

Busch added, "Collaboration is key to conservation success, and the Endangered Wolf Center is proud to partner with the Saint Louis Zoo, The Living Desert, the FWS, universities and all of the SSP institutions to help save this amazing wolf."

Thanks to the work of these organizations, the howl of the Mexican wolf, missing from the landscape for more than 30 years, can once again be heard in the mountains of northwestern Mexico and southwestern United States.

About the Endangered Wolf Center, Eureka, MO: A nonprofit organization founded by Dr. Marlin Perkins and his wife Carol in 1971, the Center's mission is to preserve and protect Mexican wolves, red wolves and other wild canid species, with purpose and passion, through carefully managed breeding, reintroduction, research and inspiring education programs. The Center is considered a cornerstone of wolf conservation in America, in fact, every Mexican wolf in the wild can trace his or her roots back to the Endangered Wolf Center. Learn more at

About The Living Desert, Palm Desert, CA: The Living Desert's mission is desert conservation through preservation, education and appreciation. The objectives of The Living Desert are: to preserve a portion of the Colorado Desert in its natural state; to foster, through interpretive exhibits, programs and publication, an awareness of, and an appreciation for, the variety of plants and animals in worldwide ecosystems; to build up under controlled conditions, populations of various species of desert animals and plants threatened with extinction in the wild state; and to foster through cooperative research and educational programs, biological studies contributing to the protection of desert species in a wild state

About the Saint Louis Zoo: Chosen as America's Top Free Attraction and Best Zoo, the Saint Louis Zoo is widely recognized for its innovative approaches to animal care and management, wildlife conservation, research and education. One of the few free zoos in the nation, the Zoo attracts more than 3,000,000 visitors a year. Learn more at