Can a sanctuary in Indonesia keep the world’s most imperiled rhino from extinction?

This article by Jeremy Hance appeared in Mongabay on June 19, 2015; visit the site to read the full article here:

“One percent of the world’s population,” veterinarian Zulfi Arsan says as he nods towards Bina, a 714-kilogram (1,574-pound), 30-year-old female Sumatran rhinoceros leisurely crunching branches whole.

A gentle and easygoing rhino, pink-hued Bina doesn’t seem to mind the two-legged hominids snapping pictures and awing at her every move at the Sumatran Rhino Sanctuary in Indonesia’s Way Kambas National Park. At least, it doesn’t interrupt her breakfast.

She also seems unfazed at this particular moment about being only one of a hundred or so—no one really knows for sure—remaining Sumatran rhinos on the planet. Today, the Sumatran rhino (Dicerorhinus sumatrensis) is probably in the bleakest state of all five of the world’s rhino species, but the 100-hectare Sumatran Rhino Sanctuary (SRS) may be the one bright spot, especially after producing a calf in 2012. The baby male, Andatu, was only the fourth rhino born in captivity in the past hundred years and the first for the SRS.

“We couldn’t stop smiling for days,” Susie Ellis, the Executive Director of the International Rhino Foundation (IRF), told me via email. Ellis, whose organization provides all the funding for the SRS, was at the birth.

 

“It was a career peak to see such an accomplishment, knowing how much effort it had taken. We sometimes said it was a 15-year pregnancy.”

But the happiness of watching Andatu grow into a healthy young male over the last three years has been marred by a string of bad news for the species.

Ellis called the Sumatran rhino’s situation “absolutely dire.”

First, there was the announcement in 2013—less than a year after Andatu’s birth—that instead of 250 Sumatran rhinos in the world, there were only about 100 left. Then in 2014, a wild female Sumatran rhino was caught for breeding in Borneo. At first conservationists thought she was already pregnant—until they discovered her womb was riddled with tumors, a common problem for female rhinos that haven’t mated frequently enough and makes natural breeding impossible. In the same year, a young female Sumatran rhino died unexpectedly at the Cincinnati Zoo.

But the worst news came earlier this year when the Bornean state of Sabah announced that the species was extinct in the wild there, which effectively meant that the Bornean subspecies was represented by only three captive individuals and maybe one or two wild ones in the state of Kalimantan in Indonesian Borneo. With the almost total loss of the Bornean subspecies—whose survival now depends on in-vitro technology—all hope for the species turns to Sumatra and, more and more, to the efforts of the team at the SRS.

The sanctuary

On the way to meet Bina, driving into the 100-hectare rhino sanctuary in Way Kambas, I couldn’t help but feel like I was inside Jurassic Park. Our open air truck was surrounded by the dense, verdant green of Way Kambas’s lowland rainforest, so thick I couldn’t see more than a few meters into the emerald gloom. On each side of the road was a tall electric fence: both to keep the ancient megafauna inside and the people—aside from the rhino’s caretakers—out. For a moment, I honestly wouldn’t have been surprised if a triceratops had lumbered out of the vegetation.

While Sumatran rhinos by no means approach the evolutionary age of dinosaurs, they are the world’s oldest surviving rhino species. Some evidence suggests that Sumatran rhinos belong to a distinct lineage of rhinos that broke off from the others around 25 million years ago, shortly following the undisputed heyday of rhino evolution and diversity. At one time, there were nearly 30 different rhino genera on Earth; today there are just three. Sumatran rhinos are the only surviving member of their ancient lineage, belonging to the genus Dicerorhinus. Some scientists think that Sumatran rhinos may even be the closest surviving relative of the lost woolly rhinos of Europe and Asia.

“Sumatran rhinos, along with Javan rhinos, are the only two rainforest-dwelling rhino species. The Sumatran rhino’s hairy body and ears make it unique among rhinos,” said Ellis.

The Sumatran rhino is also the world’s smallest, but Bina—when I see her—doesn’t by any means look small. She’s awe-inspiringly massive, with a light coat of hair and a pinkish hue. Bina, the only rhino we meet this morning, is also the oldest captive Sumatran rhino in the world. Conservationists estimate her age at around 30 and the average lifespan in captivity for a Sumatran rhino is 35.

Standing outside Bina’s pen, Zulfi Arsan tells me that the old female has irregular breeding cycles, but there is still hope that she could produce offspring. A handsome young man with a beard any hipster back home would envy, Arsan is one of the vets at the sanctuary and our guide for the morning. He just started at the SRS last year but already speaks of the rhinos here as if they are close friends.

Although theoretically Bina could still have a baby, there are difficulties. When the staff attempted to mate Bina with her only potential beau—Andalas—things got violent, says Arsan. It’s hard to imagine gentle Bina putting up a fight over anything while we watch her eat peaceably, but sex can turn even this gentle giant into a hormonal rager. Tussling before mating may be a common occurrence in the wild, but experts are loath to put any of their rhinos in danger. So, for Bina, at least, they have turned to attempting artificial insemination. An option that has yet to bear fruit.

Widodo Ramono, a Sumatran rhino expert and the Executive Director of Yayasan Badak Indonesia (YABI) (known in English as the Rhino Foundation of Indonesia), told me via email that one of the things that set Sumatran rhinos a part is a “unique breeding behavior” where females are only receptive to mating during a single day of their estrous cycle. This, not surprisingly, has made saving the Sumatran rhino “unique and challenging,” he said.

You could also call it maddening and damn-near impossible. In the 1980s and 1990s, conservationists decided on a bold plan to save the species from extinction. They went out and caught 40 individuals from the wild. But at the time no one really knew how to care for or breed them. Not surprisingly, scientists didn’t anticipate all the problems that would arise. Of the 40 animals caught in the wild, only one pair bred successfully. The rest died childless. The only survivor of that group today is Bina—captured in 1991—but she has yet to bear any offspring and her clock is ticking.

While the wild capture program has been acknowledged by conservationists as a failure—a catastrophic one—it did finally lead to the breeding knowledge researchers have today. And it was this knowledge that ended up in the birth of three rhinos at the Cincinnati Zoo, including Andalas and eventually his son—the next generation—Andatu at the SRS.

But even when breeding is successful, those working hard to save the species face a long, long wait. Rhinos breed slowly. Even more slowly than humans. A Sumatran rhino pregnancy generally lasts 15-16 months. Once the baby is born, it stays with its mother for several years as it grows, during which time conservationists keep the mother from breeding again. For example, Andatu has only recently been separated from his mother, Ratu. The separation occurred, according to vet Arsan, after the pair stopped acting like mother and son and more like potential mates. Given this, Arsan says that conservationists generally have to wait four to five years after a birth before attempting to mate a mother rhino again.

At the SRS today, Andalas has three potential mates: Bina, Rosa, and Ratu (the mother of Andatu). Ratu, who was captured in 2005 after wandering into the village, proved the perfect match for Andalas. But that took time. First Andalas, who spent the first six years of his life at the Cincinnati Zoo, had to become accustomed to his new home in Sumatra. He had to learn not to be such a picky eater (wild Sumatran rhinos feed on over 200 plant species), develop new antibodies for the jungle, and overcome parasites, according to Arsan.

But Rosa, the final rhino at the SRS, is another case altogether. Rosa was was caught in 2003 after forming a habitat of strolling into nearby villages and hanging out with humans. With her constant forays into society, Rosa became highly habituated to humans. In fact when I ask about her, Arsan makes a sideways gesture with his hand and that suggests she’s psychologically messed up. She loves being around people, he says, and “is very afraid of other rhinos.”

The team is now trying to reverse Rosa’s behaviors by keeping people away and slowly introducing her to Andalas as a mate. Arsan tells me that it’s “very slow steps, but it’s steps.”

While Andalas is the only breeding male at the SRS currently, he’s not the only potential breeding male Sumatran rhino in the world. His younger brother, Harapan, is still at the Cincinnati Zoo. Harapan has just reached breeding maturity, but all the rest of his kind live thousands of miles away. Plans are now moving forward to transfer Harapan to the SRS because, Ramono said, he “will not contribute anything [to] conservation if he sits in the U.S.”

The Borneo problem

But even Harapan is not the only possible addition to the SRS. A similar sanctuary in Bornean Malaysia also houses three Sumatran rhinos: one male, Tam, and two females, Puntung and Iman. Conservationists have kept the breeding program at the Borneo Rhino Sanctuary (BRS) separate from that of the SRS in part because the Bornean rhinos are considered a separate subspecies: Dicerorhinus sumatrensis harrissoni.

But desperate times call for desperate measures. In 2009, experts decided to treat the two distinct subspecies as a single species. Four years later, both the Malaysian and Indonesian governments agreed at a rhino summit to bring the Bornean and Sumatran rhinos together for breeding.

Still, today there has been little progress towards moving any of the Bornean rhinos abroad.

Earlier this year, Benoit Goossens, a Sabah conservationist who advocated for mixing the subspecies in 2013, blamed Indonesia for the delay.

“Indonesia is holding back! Sabah has tried almost everything in order to breed our three rhinos with Indonesian rhinos [but] Indonesia has been reluctant to do so,” Goossens wrote me via email, adding that they “will pay the price …If they think that they will be able to keep their 100 rhinos in the wild, they are wrong. The same thing [i.e. extinction in the wild] will happen to them within the next 20-30 years!”

But Susan Ellis said the situation was far more complicated than that.

“Pointing fingers at Indonesia for Malaysia’s inaction makes no sense,” she said, noting that Sabah hardly has a stellar record when it comes to rhinos.

According to Ellis, in a 2009 meeting the Borneo Rhino Alliance (BORA)—which runs the BRS—told attendees that Sabah was home to “at least 20-30 Sumatran rhinos.” Three years later, BORA dropped the number to between 10 and 22. Just one year later, they said they only had four wild rhinos.

“And now the species has been declared extinct in Sabah,” noted Ellis.

The almost hopeless state of the animals in Sabah has also led to a “a fundamental difference of opinion on [the] approach to captive breeding,” according to Ellis.

Indonesia is focused largely on natural breeding, while Malaysia is depending on unproven in-vitro fertilization technology because all three of its rhinos have major fertility problems. BORA has yet to produce a viable embryo, though John Payne, the head of BORA, told Mongabay that the group plans to have one by the end of the year.

He admitted, however, “this is tough.”

For her part, though, Ellis remains unconvinced of BORA’s strategy. For one thing, she said such procedures come with high risks during repeated anesthesia and the rewards may never materialize.

“The state of assisted reproduction in rhinos, on which Malaysia has had to place its emphasis, is very poor,” she said, adding that “despite good intentions from all parties involved, it is highly improbable that it will be perfected in time to save Sumatran rhinos.”

But if the remaining Bornean rhinos are not brought together with their Sumatran relations—and if conservationists are unable to make good with artificial breeding techniques—that means the genetically distinct line of the Bornean subspecies will be lost forever. If they are allowed to mix, that line could at least survive in part. For example, European bison today survive in two lines: one lowland breed and another that mixed the lowland with a Caucuses subspecies. Even though the Caucuses subspecies is now extinct, some of its genetic material survives in living animals. A pale victory, of course, but better than nothing.

Finally, combining the two rhino subspecies could arguably provide a potent shot of genetic diversity needed in a super-rare animal.

Still, Ellis said the final decision to bring Bornean rhinos to Sumatra does not lie with NGOS, but “at a high government level.”

A third subspecies of Sumatran rhino—Dicerorhinus sumatrensis lasiotis—once roamed India, Bangladesh, Bhutan and Myanmar. It is believed likely extinct today, but some conservationists hold out hope for a population surviving in remote Myanmar.

What about the wild rhinos?

Efforts to breed rhinos in captivity are only one part, and arguably the less important part, of the effort to save the Sumatran rhino from extinction. Beyond the electric fences of Sumatra’s rhino sanctuary, around a hundred Sumatran rhinos still roam the island’s dwindling wild. But unlike, say Javan rhinos, these rhinos are split into small, disconnected populations.

Conservationists believe between 94 and 138 Sumatran rhinos survive in total. A few—literally just a few—may be holding on in Indonesian Borneo (Kalimantan), but the majority are found in three parks in Sumatra: Bukit Barisan Selatan, Gunung Leuser National Park, and Way Kambas. Unfortunately, none of these three populations are connected, and even they are split into about ten subpopulations with between two and fifty rhinos apiece.

This puts the remaining wild populations at grave risk of simply winking out one-by-one.

“What we know from modeling is that these populations cannot tolerate any poaching and that populations of less than 40, if they are not growing, are not likely to survive,” Ellis said. She added that the strongest populations are in Way Kambas and Gunung Leuser, while the population in Bukit Barisan Selatan is “teetering on the brink of being nonviable.”

A common solution to disconnected populations such as these is to create corridors of natural habitat to bring the animals back together. But both Ellis and Ramono said corridors are not feasible in this case.

Sumatra has one of the world’s highest deforestation rates. Between 2000 and 2012, the island lost 2.86 million hectares of forest—an area larger than Haiti—according to a paper in Nature Climate Change from last year. In all, the island has lost around 85 percent of its natural forest in just 50 years. Most of this destruction can be laid at the feet of the palm oil and paper industries, which have put not only rhinos at risk, but most of Sumatra’s big mammals, including tigers, elephants, orangutans, and gibbons. Although rhinos remain the most precarious.

Sumatra’s widespread forest loss—as well as growing road networks, booming villages, and other infrastructure projects—makes it impossible to connect the disconnected rhino populations.

Instead, rhino experts came up with an alternative plan during various meetings from February to May of this year. They intend to consolidate all of the remaining rhinos into two or three large populations.

“Consolidation has worked well in Africa and India and Nepal with black, white and greater one-horned rhinos and we have enlisted expertise from Africa in particular for advice,” said Ellis.

Ramono said that “relict unviable individuals” will be brought into these rhino consolidation areas “to increase the capability of [rhinos] meeting each other thus increasing the possibility to breed.”

But to do his, conservationists need to get a better idea of just how many rhinos are left, where they are located, and if they are breeding.

Despite their hefty size, Sumatran rhinos are notoriously elusive and shy, so much so that even the government-run Rhino Protection Unit rangers—who safeguard the megafauna on a day-to-day basis from poachers and snares—almost never see their charges. This makes counting them particularly difficult. While the team hopes to conduct a thorough survey of the three populations, they still need the money to do so.

“We are having a heck of a time raising the funds to get the job done, which involves ground surveys, camera trapping and fecal DNA work,” said Ellis.

On the bright side, the team has gathered evidence that wild Sumatran rhino populations are still breeding, at least in Way Kambas and Bukit Barisan Selatan National Parks.

At recent meetings, stakeholders also agreed to increase the number of rhino rangers to make sure not a single rhino is killed by poachers.

“Every animal counts,” Ellis said, adding that while it looks like the Rhino Protection Units have put a halt to poaching, it may be impossible to detect 100 percent. “We have not found evidence of poaching in the past years, but in the rainforest environment where carcasses decay so quickly, we also are not finding animals dying of natural causes.”

Determination

After an hour of hanging out and munching her breakfast—less than a stone’s throw and a single fence away from us—Bina waddles back into the deep, deep green. Each rhino has its own fenced territory covering around four hectares. She’s headed for a dip in her wallow. Arsan says the rhinos spend “maybe four to six hours in the mud pits” and each pen has at least two wallows for the rhinos to enjoy. It makes sense given the heat of the forest at midday, the multitude of insects, and the likely soporific effects of digesting so many plants.

Her departure also marks the end of our morning at the SRS. We head back to our lodge and, like Bina, catch a midday catnap.

The SRS received its first rhinos in 1996. Twenty years later its goal has become only more difficult: namely to save the Sumatran rhino from extinction. But Ellis said that the sanctuary has allowed scientists and conservationists the chance “to study a species whose basic biology, until recently, was unknown.”

“We now understand nutrition, basic biology, reproduction, and behavior on a level we never have before,” she added. “Our challenge is to take that knowledge and apply it, so that the SRS population can truly support wild populations. ”

Most importantly—decades of work at the SRS and Cincinnati Zoo—has made breeding possible, if by no means easy.

“We’ve cracked the nut—we know how to breed Sumatran rhinos successfully and this is do-able,” said Ellis. “But it will take enormous resources as well as political support within Indonesia to take some risks [to save the species].”

With time—meaning probably decades—the team hopes it will be able to release rhinos born at the SRS back into the wild to augment those populations and increase genetic diversity.

Conservation always means playing the long game. For Sumatran rhinos, that game is even longer. Long life spans, slow breeding, and an increasingly perilous position in the wild means many of the conservationists who have dedicated their lives to this species will never know the end game of their efforts. Instead, they must live in faith and hope.

Back at our lodgings, I thought about those conservationists. I was almost surprised that they didn’t seem despondent, but determined. The odds may not be with Sumatran rhinos, but human determination has beaten the odds before. And maybe, just maybe, it can do it again.
AUTHOR: Jeremy Hance joined Mongabay full-time in 2009. He currently serves as senior writer and editor.

By Tan Cheng Li, The Star, 2 June 2014

Mistakes of the past have cost us many rhinos. Now’s the time to learn from the errors.

Between 1984 and 1995, a total of 22 Sumatran rhinos were captured in Peninsular Malaysia and Sabah for a captive breeding project. Except for one which was already pregnant when captured, none bred while in captivity, and all have since died.

Today, there are three captive rhinos in Sabah, taken from the wild in recent years – a male in 2008 and two females in 2011 and in 2014. They are our last hope to breed the critically endangered species in a final bid to boost their numbers.

In the wild, exact numbers are unknown, but rhino experts say the species is most likely extinct in Peninsular Malaysia and on the verge of extinction in Sabah, which has fewer than 10. In short, the Sumatran rhino is “functionally extinct” in Borneo and in Malaysia – meaning that the few individuals remaining are insufficient to save the species.

How did we reach this dire state? A paper “Preventing the extinction of the Sumatran rhinoceros” by three experts from the Borneo Rhino Alliance (Bora) gives a critical account of how Malaysia blundered in its attempt to wrest the species from the brink of extinction.

It points to a combination of lack of knowledge on rhino reproduction biology, poor husbandry and veterinary care in captive centres, a misguided approach in focusing on protecting rhinos in the wild, and lack of co-operation between rhino range states that led to today’s rhino crisis. The paper was authored by Bora chairman Dr Abdul Hamid Ahmad, executive director Dr Junaidi Payne and veterinarian Dr Zainal Zahari Zainuddin,

“There is finally a realisation in Malaysia that it muddled through with Sumatran rhinoceros in the past 50 years, recycling fabricated population estimates and refraining from making necessary conservation decisions,” states the authors in the paper published in the Journal Of Indonesian Natural History (December 2013). It also publicly reveals for the first time, information on the causes of deaths of captive rhinos.

Hunted out

Rhino horns have long been favoured as a folk remedy. In the first decades of the 20th century, extensive hunting had already led to a precipitous decline in its distribution and numbers. By the mid-20th century, the species was depleted from its former range and in danger of extinction in Malaya and Borneo and elsewhere on mainland Asia.

By the early 1980s, wildlife experts estimated the Malaysian population at between 52 and 75, including 20 to 25 individuals in the Endau-Rompin area in Johor, and 15 to 30 in Sabah. In 1995, Dr Zainal found evidence of only five adult rhinos in Endau-Rompin, showing that published estimates of rhino numbers were notoriously unreliable, and that actual numbers had declined by half over the preceding decade.

The United Nations-led Sumatran Rhinoceros Conservation Strategy project (1995–1998) also pointed to a dwindling population, but “… inflated numbers kept appearing in public domain, largely due to some proponents’ disbelief that two decades of effort had failed.” As recent as 2007, official figures still put the rhino population at 70 to 100 in Peninsular Malaysia and 30 in Sabah. The far-from-accurate population figures could have jeopardised conservation efforts.

After the plight of the Sumatran rhino surfaced in the early 1980s, the International Union for Conservation of Nature in 1984 convened the first Sumatran Rhino Crisis Summit, in Singapore. Some 20 representatives from governments, zoos and wildlife institutions made plans to prevent the species’ extinction, which included enhanced protection of wild rhino populations, raising awareness, and developing a global captive breeding population.

From 1984 to 1995, 22 Sumatran rhinos were captured in Malaysia (see table) for a breeding programme. At that time, nothing was known of rhino reproductive biology. The paper says an analysis reveals several kinds of failures which should not have been allowed to occur with such a precious, critically endangered species.

Many rhinos were kept in conditions which caused them poor health and stress. It was known that rhinos live in closed-canopy forest and typically wallow in clean mud for five to six hours daily. However, most captive rhinos were kept in conditions of exposure to sunlight and in some cases without access to clean mud wallows. Frequent sunlit conditions have been linked to partial and complete blindness in some captive rhinos. Other mistakes included feeding unsuitable milk to an infant rhino and unsuitable enclosures which caused one rhino to be trapped between bars, and asphyxiate.

 

Deaths at rhino centres

Most shocking of all, basic hygiene was generally poor. Some rhinos were kept for long periods in facilities that lacked basic hygiene protocols and biosecurity measures, leading to bacterial infections and eventually, deaths. There was also a lack of experienced veterinary care, causing identification and treatment of disease to come late or not at all. Prior to the development of the Sungai Dusun Rhino Conservation Centre in Selangor, rhinos were maintained at Melaka Zoo, where treated piped water was installed only after the deaths of Sri Delima and Julia.

The tragic death of all six rhinos at Sungai Dusun between April and November 2003 put an end to the captive breeding effort. The cause of deaths was reported to be due to trypanosomiasis originating from buffaloes on nearby land. The paper disputes this. It says long-term monthly monitoring of blood for parasites and blood parameters showed no trypanosomes (a parasitic protozoa) in the rhinos. Also, no trypanosome infection was detected in the blood of the buffaloes. In the post-mortem, trypanosomes were detected in only two of the seven rhinos that died, while abundant bacterial growth was found in the vital organs; mucoid Escherichia coli in five animals and Klebsiella pneumoniae in four.

The paper states that the death of male rhino Shah in January 2002 from mucoid E. coli should have prompted the facility to be on strict alert. Sensitivity tests were done in 2002 and gentamycin was found to be the only effective treatment but it was not used on the ill animals. (The tragedy recurred seven years later – from Sept 17-29, 2010, seven Malayan tapirs died from mucoid E. coli at Sungai Dusun, which by then had been turned into a tapir breeding centre. Only one tapir showed trypanosomes in the blood.)

The paper says trypanosomes might have infected the rhinos and tapirs at any time at Sungai Dusun, and that natural resistance effectively suppressed their growth until the advent of poor health and compromised immune response resulting from chronic mucoid E. coli and Klebsiella infection.

“The conclusion that trypanosomes were the cause of the Sungai Dusun deaths may have been reached erroneously, in order to allow parties involved to avoid responsibility for chronic poor hygiene in the facilities,” says the paper.

It sums up the reasons for the failure of the 1984-1995 effort on captive breeding:

> Insufficient knowledge of Sumatran rhino breeding biology and inadequate high-quality veterinary care and husbandry in captive facilities.

> Unsuitable diet in some facilities, with insufficient attention paid to the risk of iron ferritin disease.

> Stress on rhinos due to weaknesses in facilities design and poor visitor control.

> Over half of all female rhinos have reproductive tract pathology, making natural breeding difficult or impossible.

> Absence of suitable males in Peninsular Malaysia; males in Sabah with low or no sperm production.

> Rhinos were not shared between Peninsular Malaysia and Sabah due to beliefs that they were different subspecies, and between Peninsular Malaysia and Indonesia due to loss of trust after the initial exchange.

> Rhinos were not sent to the United States for breeding programmes.

> Some pairings involved inexperienced or incompatible rhinos.

> Artificial insemination was never attempted due to lack of knowledge.

Failure in preserving wild rhinos

With the deaths of the captive rhinos, the breeding project became unpopular and the focus shifted to saving rhinos in the wild rather than bringing them into fenced, managed conditions. This proved to be a misguided approach as according to the paper, no one knows for sure whether wild populations are of sufficient size and fecundity to assure their survival, even in the absence of poaching.

Moreover, this approach does not address the impact of various factors on small, isolated wild populations or the Allee effect, which refers to a “positive correlation between population size or density and the mean individual fitness”. The Allee effect states that when a population declines to very low numbers, breeding success declines in tandem. This is because factors associated with low numbers (difficulty in finding a mate, narrow genetic base, skewed sex ratio, reproductive tract pathology linked to long periods without breeding) contribute to drive rhino numbers lower and lower, even in places with suitable habitat and no hunting.

“In small, scattered and non-contiguous populations, it is just a matter of time before the average annual death rate exceeds the annual birth rate, and before the population goes extinct.” The authors of the paper believe that the Allee effect was significantly impacting survival of wild rhinos because:

> All records of wild juveniles were anecdotal, with no information on actual annual increase (or decrease) in wild population size.

> Rhino numbers have been very low for many decades in most if not all areas where they are still present, so inbreeding was likely.

> A skewed sex ratio was observed during the capture of rhinos from 1984 to 1995. The male to female ratio was 1:9 in Peninsular Malaysia and 8:1 in Sabah, and all the captured males were old.

> Reproductive tract pathology is common in the captured females, a phenomenon associated with lack of either breeding or carrying of foetuses to successful birth.

“The Allee effect has likely been present in all Sumatran rhino populations over an extended period, effectively entering the Sumatran rhino into the extinction vortex irrespective of whatever protective measures might be put in place in the wild,” declares the paper.

The lesson from Malaysia, it says, is that the priority should have been to increase the number of rhino pregnancies rather than to hope that the mortality rate of wild rhinos through poaching could be reduced. “Protecting wild rhinos may be an over-ambitious option and captive breeding may have a greater chance of success than prevailing wisdom admits.”

What now?

Last April, 100 wildlife experts convened the second Sumatran Rhino Crisis Summit in Singapore. They concluded that without immediate and committed conservation intervention, the Sumatran rhino will go extinct soon. Indonesia and Malaysia were urged to collaborate.

Simulations done during the summit showed that the species stands a good chance of surviving if there are at least 30 individuals with a birth interval of three years or less. The future of populations smaller than that is bleak even if they are healthy and protected. Using a more realistic birth interval of seven years, a starting population of 50 rhinos will have a negative growth rate of about -3% per year.

“This means that, without intervention, all possible known wild and captive populations are in an extinction vortex and are not sufficiently abundant to increase populations in isolation of each other.”

The paper says to reduce the current captive population’s extinction probability to below 10%, some 16 rhinos need to be transferred into captivity and managed with an interval of three years.

To date, there have been only four captive births, all descendants from the same pair in Cincinnati Zoo, the United States. The Sumatra-caught rhinos, Emi and Ipuh, both fertile and compatible, had received excellent care there, resulting in rhino births in 2001, 2004 and 2007. Their offspring, Andalas, was sent to the Sumatran Rhino Sanctuary in Way Kambas National Park, Sumatra, in 2007 and five years later, fathered a male calf.

 

Lesson learned

“Much of the fear over captive breeding stems from past failures,” says the paper. “But knowledge on rhino biology, animal husbandry and reproductive technology has improved.” Advances include the cryo-preservation of egg cells by vitrification, successful artificial insemination and subsequent live births of the white and Indian rhinos, and in vitro fertilisation.

The paper points to a general consensus that the sole imperative now is to produce Sumatran rhino embryos. This can only be done by bringing every rhino into closely managed facilities, and making maximum use of their gametes.

“Having these rhinos and gametes as part of a globally managed meta-population (separated populations, but with some interaction) is essential, and attempts at natural breeding and artificial insemination must continue as long as either is possible.”

The paper states that in the absence of agreement to share rhinos and gametes between nations and facilities, the current scope in Malaysia is limited. Thus, a key element of current effort is the cryo-preservation of gametes and cells that might be used in the future to restore the species after its extinction in Malaysia.