During the evening hours of Wednesday, 9 February 2020, two cheetah cubs were born at the Columbus Zoo and Aquarium in Powell, Ohio. While this is already a significant achievement, their births are even more cause for celebration as they marked a scientific breakthrough—the cubs are the world’s first cheetahs ever to be born via in vitro fertilization and successful embryo transfer into a surrogate mother.
The births are the result of careful planning and innovative medical expertise through a partnership between the Columbus Zoo, the Smithsonian’s National Zoo and Conservation Biology Institute (SCBI) in Front Royal, Va., and Fossil Rim Wildlife Center in Glen Rose, Texas—three leading institutions with a commitment to conservation. These efforts were also part of a breeding recommendation from the Association of Zoos and Aquariums’ Species Survival Plan® and the Cheetah Sustainability Program (CSP), developed to manage a sustainable population of cheetahs in human care.
While the cubs’ biological mother is Kibibi, the cubs were delivered at 9:50 p.m. and 10:20 p.m. by Isabelle (Izzy). The cheetahs’ care team observed the births through a remote camera and continued to monitor Izzy and her cubs around the clock, noting that first-time mom, Izzy, was providing great care to her little ones. The care team performed a well check on the cubs on 21 February and determined that Izzy gave birth to a male cub and a female cub. The first weigh-in showed that the male was 480 grams while the female weighed 350 grams.
“These two cubs may have started out tiny but they represent a huge accomplishment, with expert biologists and zoologists working together to create this scientific marvel,” said Dr. Randy Junge, the Columbus Zoo’s vice president of animal health. “This achievement expands scientific knowledge of cheetah reproduction, and may become an important part of the species’ population management in the future.”
With in vitro fertilization, or IVF, sperm and eggs are fertilized in a laboratory and then incubated to create embryos. The embryos are implanted into a female’s womb, where they may develop into fetuses. IVF has become a more common process with humans and some other species, but it previously has been unsuccessful in large cats, including cheetahs and lions.
Female cheetahs Kibibi and Bella first received hormone injections on 14 November 2019 to stimulate follicle development. Eggs (oocytes) were taken on 19 November from six-year-old Kibibi and nine-year-old Bella, whose genes are considered to be valuable in maintaining a strong lineage of cheetahs in human care. Izzy and her sister Ophelia’s bloodlines are already well represented in the genetic registry, so they were selected as surrogates. After the age of eight years, female cheetahs’ ability to reproduce declines significantly, and because Izzy and Ophelia are three years old, they have a better chance to safely deliver healthy, full-term cubs.
Once Kibibi and Bella’s eggs were extracted, the eggs were then fertilized on 19 November 2019 in a Columbus Zoo laboratory using thawed semen originally collected in February 2019 from two cheetahs: a male from Fossil Rim Wildlife Center and another from SCBI.
On 21 November, the early stage embryos from Kibibi were then implanted into Izzy while embryos from both Kibibi and Bella were implanted into her sister, Ophelia, by Dr. Adrienne Crosier, a cheetah biologist with SCBI; Dr. Pierre Comizzoli, research biologist at SCBI; and the Columbus Zoo veterinary team. It was only the third time scientists had ever attempted this procedure.
On 23 December, an ultrasound revealed the remarkable news: two fetuses were growing in Izzy, although none took hold in Ophelia. The father of the cubs is three-year-old Slash from Fossil Rim Wildlife Center.
“I am very proud of the team for this accomplishment,” said Jason Ahistus, carnivore curator at Fossil Rim Wildlife Center. “It gives the cheetah conservation community another tool to use in cheetah management, both in situ and ex situ. It really opens the door to many new opportunities that can help the global cheetah population. This is a big win for the cheetah.”
As a cheetah’s gestation is typically 93 days and her due date was estimated to be 22 February, Izzy’s care team put her on a 24-hour birth watch in her private den area beginning on 16 February, and the Zoo’s veterinary team stood ready with an incubator warmed up in case the cubs arrived early. Because complications during a birth can occur, the team also was prepared to perform an immediate Caesarean section if Izzy or the cubs became distressed.
The Columbus Zoo has extensive experience with cheetahs, having raised many cubs. Izzy, Ophelia and Kibibi are three of the Zoo’s ambassador cheetahs, most of whom arrived at the Zoo to be raised by hand when their mothers were unable to care for them. As a result, the cheetah ambassadors are accustomed to humans and have formed extremely close bonds with their care providers. The cheetahs are trained to voluntarily allow ultrasounds, X-rays, blood draws, and other medical procedures, so the risks of anesthesia often can be avoided. Their training also allowed Zoo staff to be near Izzy during the delivery to assist, if needed.
“In the 19 years that I’ve worked with cheetahs, one of the big challenges is that we have no idea if a female is pregnant until at least 60 days following a procedure or breeding. Working with the Columbus Zoo and Aquarium was a game-changer because their females are highly cooperative. We knew that Izzy was pregnant at five weeks by ultrasound and we continued to collect ultrasound data throughout her entire pregnancy. It was a remarkable opportunity and we learned so much,” said Adrienne Crosier, cheetah biologist at the Smithsonian Conservation Biology Institute, one of the scientists who performed the embryo transfer.
“Our animal program is the perfect setup for this type of science,” said Suzi Rapp, the Columbus Zoo’s vice president of animal programs. “We’re known in our zoological community as experts in raising cubs. If the Cheetah Species Survival Plan has a litter with problems, we’re typically the ones who are called, and we are proud to be able to assist.”
That expertise was soon needed. While Izzy was an attentive mother, close observations and regular checkups by the Zoo’s team indicated the female cub was not gaining enough weight, which required staff to intervene. Since a mother cheetah’s milk will dry up when caring for one cub, it was determined that both cubs needed to be raised by the cheetah hand-rearing team to give them the best chance at survival. In addition to caring for the cubs, the team continued to observe Izzy, who adjusted quickly to being placed back with her sisters, with whom she shares a close bond.
As Izzy also shares a strong bond with her care team, she voluntarily allowed them to express milk from her. In continued collaboration, the Columbus Zoo contributed cheetah milk samples to the Smithsonian’s National Zoo and Conservation Biology Institute’s milk repository—the first cheetah milk the repository has received. With more than 15,000 frozen samples of milks from more than 150 species, it is the most extensive collection of exotic animal milks in the United States. Information gathered from milk samples contributes data for developing formulas for newborn babies that are unable to feed from their mother.
Now, months later, the cubs continue to be doing well and are growing rapidly. They have also received very special names. The female cub is named Adrienne while the male cub is named Dave. These names are a nod to Dr. Adrienne Crosier and Dr. David Wildt, whose work resulted in this scientific breakthrough. Adrienne is a cheetah biologist for the Smithsonian’s National Zoo and Conservation Biology Institute’s Center for Species Survival. The late Dr. Wildt retired as the director of the Smithsonian’s Conservation Biology Institute’s Center for Species Survival in December 2018. A renowned leader in conservation biology, his prolific breakthroughs in reproductive biology and population genetics benefitted endangered wildlife.
Additionally, the cubs have befriended a new playmate. Campbell (or Camp for short) is a labradoodle and golden doodle mix, and he joins the Zoo’s experienced cheetah dogs, Labrador retrievers, Coby, Cash, and Cullen. Cheetahs are naturally skittish animals and would rather flee than fight. Dogs like Camp and the other cheetah dogs bond with the cheetahs and help give them an extra boost of confidence. In their native range, cheetahs face threats from farmers who are trying to protect their livestock. The Columbus Zoo works closely with several conservation groups, including Cheetah Conservation Fund, to provide Anatolian shepherds as guard dogs for the farmers. Since cheetahs are naturally flight (not fight) animals, these dogs are a great deterrence, which in turn protects the farmers’ livestock and the cheetahs, too.
According to the International Union for Conservation of Nature (IUCN), cheetahs have a population classification of “Vulnerable” and a decreasing population trend in their native range of Africa. Due to threats including habitat loss and fragmentation, conflict with livestock and game farmers, as well as unregulated tourism, cheetahs now inhabit just 10 percent of their historic range. This geographic separation has left the species genetically “bottlenecked,” creating the potential for inbreeding. Scientists estimate that the cheetah population has declined to only approximately 7,500 individuals.
The achievement at the Columbus Zoo brings the potential to help ensure the survival of cheetahs in their native range. Conservation scientists have long sought ways to boost the numbers and help maintain genetic diversity of the species. Yet, attempts to artificially inseminate cheetahs often have not been successful, with the last one occurring in 2003.
IVF previously had been somewhat successful in small domestic cats and African wildcats, but it is still rare in larger cat species, with only the birth of three tiger cubs reported back in 1990. These breakthrough births mark a significant advancement in the field, and may provide valuable information to boost future conservation efforts in cat species.
“The first thing we had to do is show that this technique works,” said Dr. Junge. “Then we have to become proficient in it, so we can do it efficiently and reliably. With experience, we may be able to freeze embryos and transfer them to Africa.”
Through other conservation projects in Africa, the Columbus Zoo also works with communities in cheetahs’ natural range, assisting with cheetah health exams and learning more about cheetah populations through camera traps, scat analysis, and habitat monitoring.
“Today’s zoos stand on the forefront of conservation efforts, and these cubs represent one of the crucial ways that zoological professionals contribute to saving wildlife and wild places,” said Tom Stalf, president and chief executive officer of the Columbus Zoo and Aquarium. “It takes teamwork, sound science, and dedication to help protect these species, and we’re devoted to that cause. Our efforts here in Ohio, our collaboration with our zoological colleagues, and the support of our community are all key to us being able to be part of dedicated cheetah conservation projects so we can make a difference.”
Top Photo: © Amanda Carberry, Columbus Zoo and Aquarium
Middle and Bottom Photos: © Grahm S. Jones, Columbus Zoo and Aquarium