Sex education is hot topic for wolf scientists

Mexican wolves that roam the hills of Arizona and New Mexico don't know it, but their Minnesota cousins did them a huge favor last week.

The Southwestern wolves are endangered, so scientists tested 14 Minnesota gray wolves as surrogates to learn more about wolf reproduction.

It got personal.

Eight male wolves donated sperm. Six females had their reproductive organs probed and viewed on monitors.

The goal of those and other tests is to improve the chances that artificial insemination can rebuild the endangered Mexican wolf population, said Cheryl Asa, reproductive biologist at the St. Louis Zoo.

The zoo team found an ideal lab at the Wildlife Science Center in Forest Lake. The nonprofit center cares for more than 50 gray wolves that have been orphaned, injured or are unable to survive in the wild for other reasons. They and other animals are used for scientific research and education programs.

All of the procedures were safe and the wolves were anesthetized, said Peggy Callahan, executive director of the center. "Under anesthesia the wolves don't have any pain, and they don't have any sensation, and they don't have any awareness," she said.

From Minnesota to Mexico

The Minnesota wolves are not in jeopardy, but the Mexican gray wolf came within a whisker of extinction by the 1970s. "It basically came down to seven wolves," said Dan Stark, wolf specialist at the Minnesota Department of Natural Resources. The Mexican gray wolf is slightly smaller than its northern relative, has larger ears to dissipate heat, and lives in mountains and forested areas. In the United States, it went extinct in the wild decades ago, largely from hunting and poisoning by ranchers.

Biologists captured the five remaining wild wolves in Mexico and began a breeding program with a few captive ones in the United States. Today, there are about 300 Mexican wolves in zoos and other institutions, and 50 have been reintroduced into wild areas of Arizona and New Mexico.

Stark, who worked on those reintroductions for 10 years before coming to Minnesota in 2007, said the research in Forest Lake will help scientists maximize the remaining genetic diversity of the Mexican wolves.

One of the questions tested with the Minnesota wolves is how long it takes females to ovulate. Six females were implanted on Jan. 6 with a synthetic hormone to stimulate ovulation. Scientists checked the condition of each female last week by inserting an endoscope and viewing the womb on a monitor. Others checked the vital signs of unconscious wolves lying on pads on the floor, waiting their turns on the examination table.

Asa said that learning more about the optimal time for insemination is critical to success, because wolves ovulate only once per year. "There are only two to four days that it's appropriate to inseminate a female and we have to figure out when that is," she said. The team also practiced artificial insemination procedures to be used with Mexican wolves.

Technique from war vets

Male wolves underwent a different regime. A slight electric current caused ejaculation. Volunteers held the wolf as its pelvic and leg muscles twitched and contracted. Technicians collected semen in clear plastic cups for computer analysis.

Asa said the stimulation technique was first used on paraplegic Vietnam veterans who wanted to father their own biological children.

After four days of testing the wolves, the researchers learned that they had underestimated the time it takes a female wolf to ovulate, and they discovered that a different "extender" will probably do a better job of preserving semen so it can be frozen for future breeding.

Callahan said the research represents small but important steps in the quest to help the Mexican wolf return to the wild and breed naturally. "Given what society did to this animal to begin with, they need our support," she said.

Tom Meersman • 612-673-7388