A pair of cheetah cubs, a brother and sister named Justin and Carmelita, has charmed Smithsonian National Zoo visitors in Washington D.C. since their public debut in July 2012. The eleven-month old cats have shed their baby fuzz for sleek orange fur patterned with black spots. Yet despite their adult stature, the cats still act like rambunctious youngsters, chasing each other around their pen and playfully wrestling.
This is all good for now – but in a year’s time these young cats will be taken off exhibit, just like their parents before them, and started down parallel paths to confront their destiny as genetically robust cheetahs, sired to save their species from extinction.
The world has undergone a massive cheetah drain over the last century largely due to loss of natural habitats and conflicts with humans. Wild cheetah populations have plunged 90 percent, from around 100,000 cheetahs in the early 1900s to roughly 10,000 today. The situation is further complicated by low genetic variability among the species. Saving the cheetahs from extinctions means not only increasing numbers, but also ensuring the new population is genetically healthy.
In recent decades, zoos like the Smithsonian have taken on this challenge. But there’s a hitch: breeding cheetahs in captivity is not easy. And despite decades of advances in understanding cheetah biology and behavior, and cultivating cheetah-appropriate reproduction strategies, current captive birth rates are still failing expectations.
Off a quiet road, hidden in the Virginia wilderness lies the Smithsonian Conservation Biology Institute, the National Zoo’s private breeding and research facility. Built in 2007, the 3,200-acre plot comfortably houses multiple species, including one of the largest cheetah populations in the United States with 17 cats.
On January 20, 2012, Adrienne Crosier, a cheetah research biologist, noticed one of the Smithsonian female cheetahs repeatedly peeing in the same spot in her pen. Ally had never been an easy cat to interpret: Abandoned by her mom as a two-month-old, she was a “nervous” youngster. For this reason, Crosier had kept close watch on Ally for years to see if the shy, petite feline would ever showed signs that she was ready to mate. Cheetah-reared cubs can mate as early as two or three, but the biologist still had doubts about Ally at age four.
One of fewer than fifty experts in cheetah reproduction worldwide, Crosier has worked with wild and captive cheetahs for over a decade. At the Smithsonian’s Virginia campus, she advocates natural cheetah breeding, but also researches assisted reproduction methods such as artificial insemination. Her work contributes to a global effort spearheaded by the nonprofit Association of Zoos and Aquariums (AZA) to save the endangered felines from elimination.
Compared to other big cats, cheetahs are especially prone to disease and physiological abnormalities due to low genetic variability. Subsequently, the AZA has mandated that breeders only mate cheetahs from different lineages to produce cubs with good, diverse genes.
That cold day in January, Crosier had a hunch Ally was in heat, or “estrus, and ready to mate. Along with lead cheetah keeper Lacey Braun, Crosier decided to play matchmaker. Ally was temporarily whisked from her pen. Three male brothers, all equally recommended by the AZA as potential suitors, were then paraded in for a “smell test.”
The siblings curiously toured the pen, nose to the ground. Within minutes, Caprivi, a young, spry four-year old had detected the intoxicating scent of a female in heat and was enamored. Anxious to meet the mysterious feline, Caprivi started cooing excitedly, a cheetah-specific vocalization called stutter barking.
Caprivi’s brothers were not interested – not an uncommon occurrence, as cheetahs can be incredibly picky about mate choice compared to other big cats, including lions, tigers, and leopards. The two apathetic brothers were sent back to their pen, while the courting cats were prepped for a standard first cheetah date: a “fence introduction.” Caprivi was moved to an adjacent holding area, and Ally was returned to her enclosure. A metal fence separated the two pens. Despite living in the same facility for over two years, this was the first time the cats had met.
Would Caprivi like Ally in the flesh – and would she like him back? If either cat hisses, howls, or displays any other type of aggressive behavior, their breeding is called off. The keepers remain nearby, like bouncers, ready to break up a fight.
Upon seeing Ally at last, Caprivi only got more excited. He eagerly ran to the shared fence, crooning in pleasure. Ideally, Ally would also have run to the fence to touch noses or dip her hips suggestively. Instead, she stood still and silent.
Since there was no aggressive behavior, however, Crosier and Braun made the call to bring the cats into the same pen and see what happened. Whether the cheetahs mated was up to Ally: She could either sit on her butt, sending a hard Not Interested message, or take to the eager suitor.
Within ten minutes of sharing a pen the cats had mated. After which, they quickly separated – typical behavior for cheetahs, who even in the wild are more inclined towards one-night stands rather than committed relationships.
The entire courtship, from introduction to mating, took less than a day, but the ramp-up for this pairing was years in the making. It involved thousands of dollars, the coordination of three zoos, and years of closely monitoring the cheetahs.
At this point, Caprivi’s job was done. But for Ally and the zookeepers, two months down the line a turbulent delivery loomed.
Cheetahs exude elegance. With a more slender frame than lions and tigers, the sleek hunters are built to run fast—70 miles per hour fast—and look good doing it. Prized for their beauty and hunting prowess, owning cheetahs was a symbol of wealth and power in places like Egypt, India, and China. Records of collecting cheetahs date back to 3000 BC. But even back then mating cheetahs was recognized as a near impossible task.
The first record of a successful cheetah mating in captivity did not occur until the 1600s at the home of ostentatious cheetah collector Akbar the Great. A famous Indian mogul, he was purported to have owned over 1,000 cheetahs and used them as hunting companions. The second instance occurred around 300 years later at the Philadelphia Zoo in 1957. Both matings were “accidental.”
Admittedly historical cheetah collectors and zoos were not trying too hard to mate cheetahs, as wild cheetahs were seemingly abundant and easily obtainable. This relaxed breeding attitude made its own small dent in wild populations: Between 1829, when the first known cheetah was showcased in a zoo, and 1994, over 1,567 wild-caught cheetahs were transferred to some 373 facilities. Until the 1960s, most of those captive cats died within a year.
Everything changed in 1973. The United States passed the Endangered Species Act, the result of an international agreement to protect animals in danger of extinction like the cheetah. This move effectively ended the commercial cat trade overnight, says Steve Bircher, curator of mammals and carnivores at the St. Louis Zoo and director for the Center for Cheetah Conservation in Africa. Cheetahs could still travel across borders for research purposes, but the process was heavily regulated by the Department of Fish and Wildlife.
Most wild-caught cheetahs exported to zoos around the world came from Namibia. As a result, the wild populations there plummeted. When the Endangered Species Act was passed, the Namibian government decided to end its export of cheetahs categorically to all countries, says Bircher.
Except for a “gift of ten cheetahs” given to the United States in 2002 from Namibia’s President Sam Nujoma, no cheetahs have legally left the African country in over forty years, explained Laurie Marker, director of the Namibian-based nonprofit Cheetah Conservation Fund. During recent decades, Namibia’s cheetah population has rebounded slightly and now the county hosts the largest wild population with approximately 3,500 cats.
Without easy access to cheetahs, zoos were forced to redefine themselves. They shed their prodigal past and confronted the question that had nagged animal keepers for centuries, “Why are cheetahs so hard to mate in captivity?” A wave of research followed and zoos started working together. Leading the collaboration was the Association of Zoos and Aquariums, which developed the first long-term cheetah species survival plan (SSP) in 1984. The plan, which is updated annually, includes a cheetah census, as well as target cheetah population numbers, breeding strategies, and research goals.
Cheetahs were not the first animal, nor the last, to be recognized by the AZA as candidates for a species survival plan. Today there are hundreds of different SSPs for animals of all kinds, including reptiles, birds, and many mammals. But the 1980s efforts to thoroughly study and tailor captive cheetah breeding strategies paved the way for more species-specialized zoo management practices.
Observations of wild cheetahs in their natural habitat, open savannahs, revealed that they have a unique social structure. Lions live in large families called prides. Tigers and leopards are mostly solitary. Cheetahs are somewhere in the middle: female cheetahs live alone, except during child rearing, and males tend to live together in small packs, called coalitions.
The two sexes only interact to breed, and even then females are only interested if they are cycling, or in heat. Thus, the initial zoo strategy of bunking female and male cheetahs together defied the cats’ very nature.
While some researchers started watching cheetahs from afar, another group took an opposite approach and starting collecting blood, urine, and stool samples. Written into the cheetah’s genes, researchers stumbled upon the cat’s dark history. Around 10,000 years ago, cheetahs nearly went extinct. An estimated 10-20 individuals survived, the ancestors of all living cheetahs today. Consequently, current “cheetahs have almost zero percent of genetic variability,” says Steve Bircher. They are “all like brothers and sisters.”
Could the lack of genetic diversity having a lingering effect? Studies of male cheetah sperm showed startlingly low sperm counts; about one-tenth the normal counts of lions, tigers, and domestic cats, according to Bircher. This was initially thought to explain low captive birth rates until it was realized that wild Namibian males with similarly low sperm counts reproduce just fine.
“Lack of genetic variability is not what has hampered the cheetah ability to breed,” says Bircher. “Quite simply, it’s how we managed cheetahs.”
After Ally’s brief encounter with Caprivi, her body started changing. Hormone levels skyrocketed, and at meal times she gorged herself. Still, it took two months to definitively confirm that she was pregnant. By that point, she’d already moved to the facility’s maternity ward – a much larger pen with full surveillance.
Then, on the morning of April 22, 2012, Ally stopped eating, a sure sign that she was about to give birth. Keeper Lacey Braun stayed overnight, but Ally showed no change. The next morning, at 9:30 am, a boy cub was born. It was a huge victory for the National Zoo – but for the cheetah staff, the work wasn’t over yet.
Similarly to what had happened to her, Ally disappointingly abandoned her cub. “We see a lot of maternal neglect in this species, especially with first-time mothers. This was her first pregnancy,” Adrienne Crosier says.
When Braun retrieved the newborn, it had stopped breathing. Alone with the cub, she frantically pressed his chess to get the lungs pumping air again. Again and again she tried, until finally he stirred. With a rush of relief, she immediately started on the hand-rearing process. With a little baby bottle, she fed him kitten formula, the same kind available at any pet store.
To the zookeepers’ surprise, Ally resumed normal non-pregnant behavior almost immediately. “Based on Ally’s body condition and weight gain, we really thought there were multiple cubs in the litter,” says Crosier. The team anxiously watched and waited all day until it became clear Ally would not be going back into labor. With the cubs and her own life at stake, the caretakers finally intervened and moved Ally to the on-site animal hospital.
An x-ray revealed three cubs still in utero. An emergency C-section, a risky operation, was the only option. “There were about ten of us there. We had three teams of two,” says Crosier. There was one team for each cub. “The first cub had a heart beat after the surgery, but it took two hours to get him breathing easily,” says Crosier. To everyone’s relief, the first cub survived. Unfortunately the second and third cubs died.
A father on a mission, Caprivi was brought into the hospital to donate plasma, nutrient rich blood, to the cubs. This material is normally passed to cubs through nursing, but Ally was in no condition to help. Due to the operation, describes Crosier, “Ally lost a lot of blood. She was pretty close to losing her life as it was on the table.”
After that night at the hospital, the family split. Ally remained hospitalized for a week, eventually returning to her independent life; Caprivi joined his brothers; and the two cubs spent their first three weeks in a clean, isolated hospital room under intensive supervision.
On May 18, 2012, nearly four months after Ally’s fence introduction with Caprivi, the precious cubs made the near 70 mile drive to Washington D.C., their current home. There the cats were named Carmelita and Justin after the 2012 American Olympic sprinters Carmelita Jeeter and Justin Gatlin, and placed on exhibit over the summer.
Compared to other big cats, cheetahs are high maintenance. Captive cheetahs are prone to stress. They need space to run around and prefer privacy. Males need opportunities to live with other males; females need space to live alone. Attentive animal keepers need to correctly identify when a female is heat and then walk through male introductions. If a given male does not work out, ideally other eligible bachelors will be on hand.
It can be taxing for zoos to juggle specific cheetah mating demands along with those of other animals. But large, private off-site facilities, or “breeding centers,” offer a solution.
“You can look at the numbers over the last 25-30 years and the facilities that have by far had the best success are the ones that are keeping the larger numbers of cheetahs,” says Steve Bircher.
A handful of centers were initially built in the 1980s. Only in the last ten years have new centers cropped up, including the Smithsonian-run one in Virginia. The centers are spread out across the United States, from Florida to California. They range in size from 1,800 acres to 10,000 acres, and house between 12 to 30 cats.
One lingering issue is money. “When half of the [cheetah] population are in eight facilities, those eight facilities are really absorbing the cost,” says Smithsonian’s Adrienne Crosier. On average, it takes $9,000 to maintain one cheetah per year. This means centers with 15 plus cheetahs like Front Royal are spending upwards of $135,000 annually on cheetahs. Crosier is currently working on a proposal to share these costs across all AZA affiliated institutions.
Despite being one of the most studied animals, and the community commitment to these facilities, it is still a struggle to breed captive cheetahs. According to the AZA, at least 25 cubs a year are needed to maintain the current captive population and even more births are needed to increase it. Thus far in 2012 there have only been 14 cubs born, including the 2 cubs from the Smithsonian. Last year, only 12 cubs were born; in 2010, there were around 20 cubs.
Part of this difficulty stems not from getting cheetahs to mate generally, but getting the right cheetahs to mate. The heyday of captive cheetah breeding was in the 1990s. Since then, managers have been “more selective” with cat mating recommendations. And today many genetically valuable cheetahs are nearing or already past their breeding prime.
The goal is to breed cheetahs naturally, but especially with the other populations, assisted reproductive strategies could help. According to the AZA, artificial insemination “is the most practical” method. In the 1990s, female cheetahs were one of the first big cats to be successfully inseminated with male sperm outside of intercourse. But cheetah artificial insemination trials have not worked in the past 10 to 12 years, says Crosier. Even though “we changed virtually nothing.”
Another option is in vitro fertilization, where an egg and sperm are removed from a female and male cheetah, respectively. The fertilization, or combination of the egg and sperm, is done in the lab rather than in the cat. Then the fertilized egg is reinserted into a cheetah. This process oftentimes requires two females: one who donates the egg, and the other who brings the baby to term.
Crosier and colleagues have studied cheetahs beyond their breeding prime, ages nine and over. They discovered that the uteruses of older felines are prone to disease, likely a result of stress and genetic legacy issues, but their eggs are healthy. These findings were published in the journal Biology of Reproduction in 2011.
Although still in research phase, the eventual goal is to use the older females eggs for in vitro fertilization. The fertilized eggs will then be inserted into younger, healthy females. This method would preserve the genetic diversity of the older captive cheetahs, says Crosier.
Another option is ditching the genetic restrictions all together. If managers “pay less attention to higher levels of inbreeding,” Mother Nature may take care of the rest, suggests Bircher, who readily admits he is not a geneticist. History has shown that cheetahs are very resilient, he adds.
But the Smithsonian Institution, for one, has no intentions of ignoring genetics, says Crosier. For cheetahs, and many other captive endangered animals, preserving genetic diversity is just as important as making new babies.
Today, Ally’s two young carefree cubs can be seen zooming around their pen in Washington D.C. Despite their rocky entrance into this world, they are healthy and playful. But in the not-so-distant future, the cubs will start their own breeding journeys.
“If you have one animal breed and its offspring never breeds, we are losing that genetic line,” says Laurie Marker. The importance of these cubs mating cannot be overstated.
Hand-raised cubs are often handicapped by a lack of exposure to other cheetahs. Aware of this, keepers at the Smithsonian have been arranging regular play dates with the other zoo cheetahs and strict about not excessively handling the cubs. Whether the young cats successfully receive enough social skills for mating, only time will tell.
But let’s say they do – then what? “Can we still save the species?” asks Marker, who more than Crosier and Bircher is focused on wild populations.
The distant end goal is to eliminate the human stresses on wild cheetahs and rebuild their population, potentially using captive born cheetahs for this mission. But until captive breeding success rates skyrocket, the struggle of the wild cheetahs is largely being put on hold.
However, cheetahs on exhibit like Carmelita and Justin are helping to make this point. As “great little ambassadors for their species,” said Crosier, the two fluff balls are promoting awareness about cheetah conservation in their own adorable way.