Use of Human Chorionic

Use of Human Chorionic Gondadotropin in a Male Pacific Walrus (Odobenus rosmarus divergens) to Induce Rut and Achieve a Pregnancy in a Nulliparous

Scientific breakthroughs beneficial in better understanding of walrus reproduction

VALLEJO, Calif. – January 19, 2012 – After several years of research, Six Flags Discovery Kingdom recentlyreached a scientific breakthrough with the conception of one of its Pacific walruses. In the last 80 years only 11 calves have been born in U.S. facilities. The results of the park’s groundbreaking efforts, lead by marine mammal reproductive specialist Holley Muraco, have now been published in the Journal of Andrology.

In this study, the breakthrough formula for walrus conception is revealed. By watching the mating patterns and hormonal levels of walruses over a seven-year period, it was determined that male walruses, one of the few species that breed seasonally, were not fertile at the same time as the female walruses.

“It’s a great feeling when we are able to improve the fertility of other species through natural methods, as this is what we try to do in our clinics as much as we can.”
– Dr. Paul Turek

The team was comprised of Muraco, Discovery Kingdom marine mammal trainers and staff veterinarians with fertility expertise provided by Dr. Paul Turek, a men’s health and infertility specialist, founder of The Turek Clinic in San Francisco and co-author of the study.

“We simply moved his fertile window to coincide with her fertile window, and let the usual magic happen,” said Muraco.

With Turek’s help, the Six Flags team hormonally shifted the male walrus’s fertile window to coincide with the females.

“When Holley asked me to help with the hormonal approach to moving the male walrus fertile window from spring to fall, I thought ‘let’s try what works with infertile men’ and sure enough, it worked,” said Dr. Turek.

What came to light was that the mating signals of walruses are crossed because their day-night circadian rhythms are different in captivity than in the wild.

“In essence, when it comes to fertility, captive walruses are like ships passing in the night,” said Muraco. “Reproduction in walruses is seasonal and is tied to light-dark cycles. Those cycles aren’t the same in California as they are in the Arctic.”

One reason this important observation took some time to figure out is because walruses live in the Arctic cold and breed underwater in bone-chillingly cold waters where few scientists have dared to go. Therefore, due to this inaccessibility, little is known of the walrus reproduction in the wild.

Additionally, it appears that the method used is generalizable to walruses in other facilities, as the Six Flags team has since helped walruses in other parks to conceive as well. The findings have proven significant; today, there are only 17 walruses in North American facilities, three of viable breeding age that reside in the Six Flags park.

“It’s a great feeling when we are able to improve the fertility of other species through natural methods,” said Dr. Turek, “as this is what we try to do in our clinics as much as we can.”

About Six Flags Entertainment Corporation

Six Flags Entertainment Corporation is the world’s largest regional theme park company with approximately $1.0 billion in revenue and 19 parks across the United States, Mexico and Canada. For more than 50 years, Six Flags has entertained millions of families with world-class coasters, themed rides, thrilling water parks and unique attractions including up-close animal encounters, Fright Fest and Holiday in the Park.

About Paul Turek, MDFACS, FRSM

Male reproductive health expert Dr. Paul Turek is founder of The Turek Clinic, a leading health care resource for men worldwide. Dr. Turek is a recent recipient of a prestigious National Institutes of Health (NIH) grant for research designed to help infertile men become fathers. A former Professor and Endowed Chair at the University of California San Francisco, Dr. Turek has pioneered innovative techniques for treating male infertility, including Testicular Mapping. Other innovations in men’s health include the and has helped to popularize the No-Scalpel Vasectomy and has published some of the highest success rates worldwide for vasectomy reversals. Dr. Turek is an highly sought after advisor and sits on the board of several high-profile organizations, including the NIH and the Centers for Disease Control (CDC). He donates his time to help the working poor of San Francisco receive medical treatment as Chair of the Medical Advisory Board for the non-profit Clinic By the Bay. Dr. Turek blogs on a weekly basis about common medical issues, solutions and innovations.

A complete biography of Dr. Turek is available on Wikipedia at

About The Turek Clinic

The Turek Clinic is a next-generation men’s healthcare medical practice specializing in issues facing reproductive age men, including male infertility, erectile dysfunction, vasectomy, vasectomy reversal, varicocele repair, and other minimally invasive procedures. The practice was founded in 2008 by Dr. Paul Turek, a pioneer in men’s reproductive health and former endowed chair professor at the University of California San Francisco. Dr. Turek’s work combines innovative and cutting edge techniques with the wisdom of old-world medicine to treat and solve men’s health issues. For more information visit

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 Six Flags Discovery Kingdom Biologists Successful in Helping Walrus Conceive

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Use of Human Chorionic Gonadotropin in a Male Pacific Walrus (Odobenus rosmarus divergens) to Induce Rut and Achieve a Pregnancy in a Nulliparous Female

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