If you ride the Muni Taraval line all the way to its end at San
Francisco’s Ocean Beach, you might hear a lone wolf’s howl over the crashing
surf. You wouldn’t be tripping—it could be one of three Mexican wolves now
living at the city’s zoo.
The trio is settling into new digs at “Wolf Canyon,” which
opened to the public today. And the wolves aren’t just for show—they’re key to
the conservation of their wild brethren, as part the Mexican Wolf Species
Survival Plan.
The pack is part of a captive breeding program to contribute
to the genetic diversity—and therefore the survival—of wolf populations that
have been reintroduced to their historical ranges in the southwestern U.S. and
central Mexico.
“There’s a lot of talk about animal reintroduction into the
wild, but it’s not as common as the layperson thinks,” says David Bocian, Vice
President of Animal Care at the San Francisco Zoo.
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A Mexican wolf is released into the mountains in eastern Arizona as part of the Mexican Wolf Species Protection Plan. (USFWS)
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Genetic diversity is a major challenge to such programs,
continues Bocian. The more narrow the gene pool, the more vulnerable the
population.
“If they aren’t adaptable to adjust to those curve balls
that nature throws at them,” he says, “they’re not going to survive.”
Wild West vs. Wild Wolves
Mexican wolves are the smallest, southern-most subspecies of
gray wolf in North America and were almost obliterated by the early 1970s. As
the Wild West morphed into ranchland in the mid-1900s, the numbers of elk, deer
and other prey plummeted, forcing the wolves to turn to domesticated livestock.
The U.S. and Mexico retaliated with a campaign that nearly
wiped out the entire species. When the Mexican wolf was listed as endangered in
1976, the two countries made a plan.
“To get a hold of as many wolves in the wild as we can
before they go extinct on us,” says Peter Siminski, director of conservation
for The Living Desert and coordinator for the Mexican Wolf Species Survival
Plan.
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| The new wolves at the SF Zoo are part of a captive breeding program, started in the mid-1970s when the wild population of Mexican wolves had been nearly obliterated. (Marianne Hale/SF Zoo) |
The recovery team frantically caught five individuals—the
only wolves they could find—and began a captive breeding program to repopulate
the dry mountain ranges of eastern Arizona, western New Mexico and central
Mexico.
In 1998, the first pack of 11 wolves ran into their
designated habitat and began to establish territories for their families.
Today, there are around 100 individuals in the wild and more than 240 in
captive breeding facilities in the U.S. and Mexico.
“All the wolves currently in the wild came from ancestors
that were bred in captivity,” Siminski says.
SF Wolves Donate to Gamete Bank
Genetic diversity gets lost over generations, especially in
populations descended from so few individuals, says Bocian of the SF Zoo.
“We’re never going to increase it unless we stumble upon
some wild animals, and that’s not likely,” he says.
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| Three Mexican wolf brothers explore their new enclosure at the SF Zoo. The exhibit uses technology to feed the canines and limit their interaction with humans. (Marianne Hale/SF Zoo) |
Instead, the Association of Zoos and Aquariums (AZA) and the
U.S. Fish and Wildlife Service (USFWS) partner with Mexico in the Mexican Wolf
Species Protection Plan to track captive wolves carefully to prevent relatives
from mating with each other.
The partners may move male and females around to different
zoos to breed. And the three new studs at the SF Zoo will contribute to the
gene pool in yet another way.
This winter, scientists from the St. Louis Zoo will fly out
to San Francisco to collect sperm from wolves here to bring back to the Mexican
wolf gamete bank—a kind of emergency diversity fund. The gene bank also holds
eggs from female wolves.
“You can broaden out the genetic variation if you have a
gene bank you can pull from,” says Jason Watters, SF Zoo’s VP of Wellness and
Animal Behavior. “You can say, ‘OK, this guy’s line hasn’t been in the
population for a few generations. Let’s infuse him back in.’”
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| A captive Mexican wolf at The Living Desert. There are more than 240 wolves in facilities in the U.S. and Mexico. (Bert Buxaum/The Living Desert) |
A High-Tech Exhibit
The conservation story of the Mexican wolves is similar to
the story of the California condor. Condor handlers wore costumes so the birds
would stay wary of humans, and would have a better chance of surviving in the
wild. The SF Zoo has a similar goal for the wolves, but is taking a more
“Silicon Valley” approach.
Watters collaborated with Silicon Valley-based Crowd Optic
to rig the wolf exhibit with gadgets to minimize the amount of interaction the
animals have with zookeepers. By “turning on” the enclosure with various forms
of technology such as automatic feeders, the exhibit itself—rather than the
human handlers—will manage the wolves behavior, Watters says.
Visitors get to observe the wolves, but limiting direct
human contact helps retain the animals’ wild nature, making the habitat
appropriate for wolves who could be released back into the wild.
The zoo’s three new wolves are probably too old to be
released. At age 10, they are practically geriatric. Thanks to the gamete bank,
though, the wolves could father pups for decades to come.
Articles and images sourced from http://ww2.kqed.org/science/2016/06/08/endangered-mexican-wolves-debut-at-sf-zoo/
