Smithsonian National Zoological Park l Friends of the National Zoo



Finding the Silver Lining

The recent birth of clouded leopard cubs signals hope for this rare and beautiful cat.

by Cristina Santiestevan

Virginia is a long way from Thailand, and the Blue Ridge Mountains are a far cry from the tropical forests of Southeast Asia. The climate, the landscape, and even the birds in the sky are different. But there is one common link: the clouded leopard (Neofelis nebulosa). This tropical cat’s last and best hope could be here, at the Smithsonian’s National Zoo’s Conservation and Research Center (CRC) in Front Royal, Virginia.

Once a breeding and training facility for cavalry horses, CRC is now home to some of the world’s most endangered species. It is here, among old barns and modern laboratories, where JoGayle Howard is making a stand for the clouded leopard. Howard, a veterinarian and reproductive scientist at the National Zoo, is battling time and threats to save the species from a decline that could end with extinction. But clouded leopards are reluctant partners in their own salvation. Difficult, secretive, and unlike any other cat, they defy most scientists’ attempts to understand them and, possibly, save them.

But Howard can now claim to have demystified some aspects of clouded leopard reproduction. In March, one of the clouded leopards at CRC gave birth to two male cubs—the first such births at the Zoo in 16 years, and the first clouded leopard cubs born in the North American Clouded Leopard Species Survival Plan in six years. “We’re very happy—it’s been a long road,” says Howard. “These valuable cubs represent many years of Zoo research on clouded leopards.”

The National Zoo has been working with clouded leopards at CRC since 1978, with the ultimate goal of breeding these cats to create a genetically diverse population and perhaps save the species. “We’re never going to save a species we don’t understand,” explains Howard. Thus—from basic behavior to complex reproductive physiology—Howard has made it her goal to understand clouded leopards. “I feel like we’ve come a long way,” she says. “But we still have much more to learn.”

Frightfully rare and extremely difficult to study, the clouded leopard’s evasive disposition does not exactly encourage conservation projects. In fact, the National Zoo’s clouded leopard breeding and research program is the only one of its kind. “If we weren’t doing this, nobody would be doing this,” says Howard. “We are the stewards of this species.”

Clouded Leopard
Clouded leopards are hunted for their pelts throughout Southeast Asia. (Jessie Cohen/NZP)

The Ghost of the Forest

To describe the clouded leopard as secretive would be an understatement. This cat is so elusive that dedicated researchers spend years in the forest without seeing a single clouded leopard; their current range can only be guessed and population estimates vary wildly. “No one has a clue how many clouded leopards exist,” says Howard. “There could be 10,000 wild cats scattered across Southeast Asia and the surrounding islands.” But, perhaps more likely, there could be less. Significantly less.

After about a decade of trying, researchers have radio-collared and tracked only six individuals. Scientists have found that these cats—three males and three females—are most active near dawn and dusk, travel far through territories nearly triple the size of any other species of leopard’s, and sometimes venture beyond the forest canopy’s protective cover to explore grasslands and other habitats. Despite these results, data from six cats hardly represents conclusive results. Until researchers collar and track more clouded leopards, our understanding of their wild behavior is left mostly to informed speculation.

What we do know about clouded leopards suggests they are masters of acrobatics and agility. These leopards are the smallest of the big cats, weighing just 30 to 50 pounds and measuring about five feet long. Their short legs, oversized paws, and long tails—which account for half their length—help them balance on small branches, and their flexible ankles allow them to run down trees headfirst. The cats are strong enough to leap up to 12 feet between trees, and can easily climb along branches while hanging upside down. Their canine teeth—the longest of any cat’s relative to body size—suggest they may use this strength to overpower relatively large prey, such as deer and wild boar.

Combine this agility and strength with their camouflage coat, and it’s no surprise clouded leopards are as elusive as ghosts. But the habits of a ghost aren’t enough to protect clouded leopards from their greatest threat—poachers who profit from selling the cats’ coveted pelts. Camera traps—tree-mounted and motion-activated cameras used by researchers to record wildlife activity—occasionally snap photographs of wild clouded leopards. Unfortunately, every roll of film has poachers on it,” explains Howard. “Illegal wildlife trade is probably the cats’ greatest threat in Thailand.” Clouded leopards are also hunted for food or to supply ingredients for the Chinese medicine trade.

Not Your Typical Cat

The cats’ mysterious nature wouldn’t present nearly as much of a challenge if they were like other cats. But their biology is so different from other species that standard feline reproductive procedures, such as hormone therapy and artificial insemination, do not work with clouded leopards. Most felines share some common traits, potential clues that help guide researchers in their work. Both cheetahs and house cats, for example, are induced ovulators. This means they release their eggs for fertilization only when they mate. Knowing this, National Zoo scientists can manipulate a female cheetah’s reproductive cycle to induce estrus (heat) and ovulation before an artificial insemination, which would dramatically increase the chances of success. To date, the Zoo’s cheetah breeding program boasts about a 50-percent success rate with artificial insemination (AI).

Clouded Leopard

First-time mother Jao Chu gave birth to two male cubs in March. (Janice Sveda/FONZ Photo Club)

Clouded leopards follow much different reproductive cycles. These cats often ovulate spontaneously, releasing their eggs after estrus even if no mating occurs. While this is not a problem with natural breeding—after all, clouded leopards have been procreating for years—spontaneous ovulation does make it very difficult to perform a successful AI. So difficult, in fact, that the Zoo has celebrated just one successful pregnancy resulting from artificial insemination in clouded leopards. Howard describes it as “luck” and suspects the female was not cycling. The successful AI has never been repeated.

The lack of success is not for lack of trying—the Zoo’s reproductive scientists have been working to understand the reproductive physiology and hormonal cycles of these cats for two decades. After years of research, Howard has many answers but also plenty of questions. “They’re just the most difficult cat species to understand,” she says. Despite the challenges, Howard and others continue to look for answers. “Understanding how to control their cycle is critical before artificial insemination,” explains David Wildt, head of the National Zoo’s Department of Reproductive Sciences.

Howard has applied 20 years of research to the methods she is now using to artificially inseminate the clouded leopards. The most recent attempt to inseminate three of the cats—Nattie, Nelly, and JoGayle— utilized her latest methods. Since clouded leopards do not respond like cheetahs, she and graduate student Katey Pelican decided on a dramatically different approach: They stopped the reproductive cycle entirely. Using high doses of hormones, they temporarily
halted the reproductive hormonal cycle for the three clouded leopard females at CRC. The cats were then given a second hormone to restart their cycle and induce a synchronized estrus, followed with another injection to induce ovulation. The three cats also were given extra doses of progesterone after the AI, which Howard hopes will help encourage and support a pregnancy. This strategy is often used in AIs with other spontaneous ovulators, including cattle, primates, and humans.

Since artificial inseminations are so difficult, many ask why the cats aren’t allowed to reproduce naturally. As is typical with this atypical cat, there is no easy answer. Male clouded leopards are often aggressive, and have a gruesome record of attacking, maiming, or killing potential female partners. The attacks can come suddenly and without warning, and often occur during the evening.

Scientists still do not know why male clouded leopards attack, but several graduate students at the National Zoo are studying the males’ behavior in hopes of identifying clues. One of the students is testing anti-anxiety drugs used in humans and domestic cats in an attempt to suppress male aggression. So far, Howard and her team have learned how to reduce the risk of fatal attacks by introducing males to their mates when they are six months old, allowing the pair to grow up together.

Hannibal and Jao Chu, the only compatible pair of clouded leopards at CRC, are proof that this technique works. Jao Chu is the mother of the newborn cubs at CRC. Both she and her mate, Hannibal, are approximately two-and-a-half years old. Because the two were raised together and are now a bonded pair, they were able to breed successfully and become the parents of two cubs. A second pair of compatible clouded leopards—male Tai and female Mook—lives on Asia Trail at the Zoo, and they recently bred in March. Another pair—imported from Thailand like Hannibal and Jao Chu—lives at the Nashville Zoo.

It Takes a (Global) Village

Saving a species doesn’t occur in a vacuum, and clouded leopard success at the National Zoo requires input from many organizations that help with breeding efforts by supplying people-power and funds. “I don’t know how we could do it without collaborating,” says Howard, who is quick to list many partners, including the Nashville Zoo, the Point Defiance Zoo in Washington, the Khao Kheow Open Zoo in Thailand, and the Clouded Leopard Species Survival Plan, among others. “We become colleagues. We become friends. We all have something different to offer the program,” she says.

Howard is justifiably excited about the Thailand Clouded Leopard Consortium and its recent breeding successes at Thailand’s Khao Kheow Open Zoo. The Consortium—born through a partnership between the National Zoo, Nashville Zoo, and the Zoological Park Organization of Thailand—has produced 33 surviving cubs since its inception in 2002. This remarkable success provides hope for clouded leopard breeding programs around the world.

Genetic diversity is one of the most important pillars of a successful captive breeding program. If the cats are not carefully paired with unrelated partners, the captive population could become dangerously inbred. The Clouded Leopard Species Survival Plan oversees clouded leopard populations in zoos worldwide, and makes recommendations for potential pairs based on the genetics and pedigree of each cat. Since Thailand’s cubs are only one or two generations removed from the wild, their genes are especially valuable. Several have already been transported to the United States, including CRC’s Hannibal and Jao Chu.

Despite some challenges, such as losing two cats to avian flu in 2004, the Thai program is thriving. Of the 33 surviving cubs, 17 have been paired with compatible partners. Currently, two pairs are actively breeding at Khao Kheow, and another seven young pairs are successfully living together in Thailand and America.

Clouded Leopard cubs
Two long-awaited clouded leopard cubs were born at the Conservation and Research Center in Front Royal, Virginia, in March. (Jessie Cohen/NZP)

Moving Toward a Brighter Future for Clouded Leopards

Howard poses a question: “How do you save a species?” The answer—one piece of information at a time—is simple, but not quick.

After decades of dedicated study, the Zoo’s clouded leopard program has many hard-earned, valuable answers: Clouded leopards need tall, private enclosures that are separated from other pairs. Males should be introduced to their potential partners at an early age in order to reduce aggression. Hand-reared cubs mature into confident, low-stress adults that are more likely to breed successfully.

But many questions remain, and Howard continues to search for answers wherever and however they might be found. At the National Zoo, her team is refining their techniques for artificial insemination. Across the Pacific, Howard and the Thailand Clouded Leopard Consortium will continue to study, breed, and hand-rear the cats at Khao Kheow Open Zoo. Aware of the mysteries surrounding their natural behaviors, Howard hopes to expand the Thai-based clouded leopard field programs. Recently, she and other collaborators from U.S. zoos and Thailand’s Kasetart University initiated the first international meeting in Thailand about Asia’s small cats. And, proof that Howard will look anywhere for clues, her team continues to import “huge coolers filled with frozen poop” from Khao Kheow. When analyzed for fecal hormones and
DNA, the clouded leopard scat reveals valuable information about the cats’ health, stress levels, reproductive cycles, and genetics.

And in Virginia, CRC is embarking on an ambitious, multi-million-dollar project to construct new breeding and research facilities that will eventually house ten pairs of clouded leopards. Each unit will include two tall outdoor enclosures for climbing and exploring, with a connected indoor area. These new enclosures are necessary to support the National Zoo’s clouded leopard program in the coming years, and to provide a home for the new cubs.

“Most people don’t understand what conservation is,” explains Howard. “I like to think it’s everything. It’s the training. It’s the science. It’s the breeding. It’s the field programs. You can’t just do one little piece and hope to save a species. There’s just no way.”

How do you save a species? This is how. One answer, one success, one cub at a time.

—Cristina Santiestevan writes about nature, science, and conservation from her home in the foothills of Virginia’s Blue Ridge Mountains.

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