A cloned Przewalski horse named Kurt is a new attraction at the Safari Park in San Pasqual Valley.
The colt has a unique story.
It’s the world’s first successfully cloned Przewalski horse, a breed native to Mongolia that became extinct in the wild but now has been reintroduced into its former habitat.
It’s also a living legacy to Kurt Benirschke, the visionary founder of San Diego Zoo Wildlife Alliance’s endangered species reproduction center, referred to today as reproductive sciences.
Benirschke had the foresight, 42 years ago, to save genetic material from this ancient horse species in his Frozen Zoo. His team’s research discovered that the Przewalski horse has 66 chromosomes, two more than the domestic horse, confirming it as a separate species.
Sadly, Benirschke died in 2018, at age 94, before being able to witness this cloning miracle and many others on the horizon with scientific advances in reproduction technology.
His trail-blazing life was a combination of Indiana Jones — venturing into remote, inhospitable jungles — and Jurassic Park scientist — bringing to life exotic species, some already believed extinct in the wild.
His son, Rolf Benirschke, former place kicker for the San Diego Chargers, has brought to light and to life some of his father’s adventures in a book: “Saving Wildlife: The Extraordinary Life and Legacy of Dr. Kurt Beirschke.”
The doctor moved to San Diego in 1970 to UC San Diego’s fledgling medical school where he headed the pathology department.
He also ed a S.D. Zoo research committee and eventually was invited to form a reproduction research center for endangered animals in 1974. He and his zoo colleagues since have played key roles in the conservation of California condors, giant pandas, black-footed ferrets, the southern white rhino and many more endangered and threatened species.
In 2004, their Frozen Zoo preserved cells of the world’s last living po’ouli, a bird native to Hawaii, after it died of old age in a conservancy center in Maui.
Benirschke almost single-handedly saved the giant peccary. The furry pig-like South American mammal was believed to be extinct. But when discovered to still exist, Benirschke visited a remote Paraguayan village in a jungle bearing the daunting nickname of the “green hell.”
Inhabitants caught one of the rare animals for their American explorer. Benirschke immediately set up a remote zoo outpost under supervision of a villager to breed the animals.
The last male northern white rhino died in 2018, leaving only two females in a Kenyan conservancy. Hope for the species’ survival resides in tissue cultures Benirschke’s Frozen Zoo banked years ago from 12 northern white rhinos.
Some of the skin cells will be transformed someday into pluripotent cells that can be turned into egg or sperm cells to create embryos that can be implanted in surrogate rhino moms.
The Frozen Zoo, which Benirschke founded, is part of the Wildlife Biodiversity Bank and has expanded to include cell cultures and gametes from more than 10,000 animals. Nearly 1,200 rare and endangered species and subspecies are represented.
Zoo officials report that more than 44 endangered species have been reintroduced into their native habitats.
Benirschke was outspoken and relentless in his mission to save wildlife and his insistence that zoos learn reproduction techniques to preserve various species as its inhabitants age. He realized that replacement from the wild no longer will be possible.
His bread and butter was curiosity — seeking answers to questions that often led to solving genetic mysteries and unearthing new ones.
“Dad always asked: ‘Why? Why? Why?'” recalls Rolf, who is on the board of the Zoo Wildlife Alliance, which urged him to write his father’s story.
Early on, Benirschke’s curiosity was piqued by the nine-banded armadillo, which always produces identical quadruplets, and led him to take many trips to South America to study other armadillo species.
He also wondered why mules, the offspring of a horse bred with a donkey, were unable to reproduce. He discovered the answer — the horse has 64 chromosomes and the donkey has only 62. A mule has 63.
He published his findings in keeping with his belief that research is far more useful when shared. To that end, he authored or co-authored 30 books and more than 500 scientific papers.
In 1967, Benirschke began annual publication of “An Atlas of Mammalian Chromosomes” with researcher T.C. Hsu, adding the chromosome makeup of 50 new species each year.
If you ask Rolf what his father would consider his greatest contributions, one is his research on female placentas that provided clues to the health of newborns and fetal abnormalities. His textbook, “Pathology of the Human Placenta,” still is in use in medical schools today.
The other is the concept of One Medicine, later referred to as One Health, meaning humans and animals could share some of the same medical protocols and treatments. For example, an ophthalmologist for humans performed cataract surgery on a San Diego Zoo gorilla, and prominent cardiologists operated on a Sumatran orangutan named Karen born with a hole in her heart.
There actually was a “Jurassic Park” connection to the San Diego Zoo. After the art director of Steven Spielberg’s blockbuster movie-in-the-making was hosted by Benirschke and his team, a lab scene in the film was based on the appearance of the Frozen Zoo. Plus, entry gates to Jurassic Park were inspired by gates at the Safari Park.
It was an odd pairing, indeed, when Benirschke teamed up with artist Andy Warhol to produce a 1986 book, “Vanishing Animals.” The doctor wrote the text, and Warhol created colorful illustrations of 30 animals.
Rolf participated in many of his father’s adventures as a youth. Together they tracked barn owls in North County, mapping their nest locations and collecting pellets of regurgitated food to dissect and determine the owls’ diet.
As a summer zoo intern from 1974-1976, Rolf helped collect blood, tissue, stool and urine samples for research. He pursued a zoology degree from UC Davis but changed career plans after he was drafted by the NFL.
He and another intern performed key research on Galapagos tortoises. Shell and neck shapes varied depending on which island the tortoises lived. “My job as an intern was to see if they were separate species,” says Rolf.
Their study of chromosomes confirmed the tortoises were actually subspecies.
The two interns, likewise, performed a key service when the zoo had difficulty breeding parrots because males and females appeared identical in size and color. They collected fecal samples to measure the levels of estrogen and testosterone to determine sex.
Rolf describes his mother, Marion, as the glue that held the family together through their escapades — many of which occurred in the middle of the night when Kurt got a call that a zoo animal had died, or had given birth, or was under an anesthetic.
Rolf was often at his side as he rushed over to collect samples of skin, placenta, tissue, eggs or sperm for study and preservation. “We’d get back at 5 a.m., and at 6:30 I’d have to get up for school,” Rolf recalls with a smile.
Three weeks ago, after the cloned colt was put on display with a Przewalski female named Holly, trustees were driven out to visit his habitat.
What would Rolf’s father say about the cloned Mongolian horse bearing his name?
“He would brush it off,” said Rolf. “It was never about Dad.”
