One wildlife veterinarian's quest to save Sumatran rhinos from extinction

The way Dr Benn Bryant describes the Sumatran rhinoceros – “a pelt of shaggy orange hair”, “dagger-like incisors,” “predisposed to wallowing”, with “whistling and squeaking vocalisations” – it sounds more like it romped from the pages of a children’s book than the Indonesian island of Sumatra.

“They’re a very cryptic animal,” the veterinarian says of this most ancient of rhino lineages (it’s more closely related to the ancient woolly rhino than the others living today). “They’re solitary and shy, living in very dense forest habitats.”

One of the world’s five species of rhinoceros, the Sumatran is also the smallest, though it can still weigh up to 800kg (African rhinos go up to 2500kg). It used to range across Southeast Asia and all the way up to China, but the few that are left now take advantage of the remaining habitat in Borneo, Indonesia. And yes, Sumatra.

When he speaks to SAM, Dr Bryant has just returned from the Sumatran Rhino Sanctuary, a 250-acre complex in Way Kambas National Park. The sanctuary is supported by the International Rhino Foundation, of which Taronga Western Plains Zoo is a founding member, and as Taronga’s Senior Veterinarian, Dr Bryant is on stand-by for emergencies.

He deals with all creatures great and small, particularly with Taronga Western Plains Zoo being home to many species of large African hoofstock, but it’s the Sumatran rhino – thought to be the most endangered large mammal in the world – that Dr Bryant is most aligned with. Though he’s had a strong conservationist streak since his days as a veterinary science student, “Conservation of species is an ethical obligation for humanity,” he says.

It’s thought there now could be as few as 70 or 80 Sumatran rhinos left, as a result of poaching and habitat loss. Seven of those are in the sanctuary in a breeding program, because wild population density is so low that the animals will rarely cross paths naturally.

Critics of captive populations argue that genetic diversity and behavioural patterns can be lost, and certainly decades-past attempts to create breeding programs have not been as successful.

“Back in the ’80s contingency captive population in zoos were established in zoos,” Dr Bryant says. “But that strategy failed abysmally. The feeding ecology and nutritional requirements were poorly understood and Sumatran rhinos are very aggressive toward each other, except when they’re in breeding condition, so attempts to introduce them were quite disastrous.”

In the mid-’90s the surviving animals were repatriated back to Indonesia, with most of them ending up in the Sumatran Rhino Sanctuary. The difference here is that they aren’t fed by keepers. Instead they’re free to browse native trees and shrubs to get their nutritional requirements. Hard-learned lessons around their reproductive physiology have also been taken on board. 

Unlike other rhino species and indeed most mammals, Sumatran rhinos are what’s called induced ovulators. The females don’t actually ovulate until after they’ve mated. Scientists were stumped by this in the past, as they would normally look for an ovulated egg to signal the time for mating.

So how do you know whether an animal is ready for mating if it doesn’t ovulate first? The modern answer for Sumatran rhinos is monitoring by ultrasound, or more specifically, transrectal ultrasonography, which uses sound waves to produce a picture of the key organs. To date, this method has seen five calves born in human care, to two different females. Though it is, in its way, a gamble.

“Of course, it’s extraordinarily risky to capture a large vertebrate in a remote jungle environment, move it perhaps hundreds of kilometres, unload it into a semi-artificial environment, and impose a human care system on it,” Bryant admits. “But risk-benefit assessments are made, and Sumatran rhinos are on an extinction trajectory.”

Another animal challenge that Bryant has faced, is getting a lion on an operating table because it needed root canal therapy. Of course, in these situations, proper sedation is a priority.

“Many of our animal patients are dangerous and aggressive,” says Dr Bryant. “They are inherently wild and so have a vigorous fight or flight response. Different animals have different behavioural responses and different weapons. Controlling them might mean a brief period of physical restraint of a small mammal or bird and administering anaesthesia in oxygen by facemask. With larger animals like lions, it might be by a dart. Or it might be the animal might happily submit to standing by a fence.”

For the record, Bryant says one of the trickiest animals to fit effectively onto an operating table is an ostrich.

Dr Bryant grew up in suburban Sydney in the ’70s, exploring creeks and wild spots of local bush. His backyard shared a fence with a couple of hectares that were home to dairy cows. “We had family friends who had a dairy farm and we would go and milk their cows and run their operations for them when they went on holiday,” he says. “All those experiences consolidated into a conviction that veterinary medicine was the path for me.”

Like many kids of the era, he enjoyed the books of vet James Herriot, best known for the All Creatures Great and Small series, later made into television and films. To this day, the public is fascinated by the life of vets, with no fewer than six reality TV programs dedicated to the profession.

After working in private practice for nine years, dealing with rather less exotic species than he does now, Bryant applied for a wildlife medicine residency at Taronga Zoo in Sydney, and concurrently enrolled in a Masters of Veterinary Studies in Wildlife Medicine and Husbandry through the university.

Taronga now offers a program as an extramural training partner of Sydney University’s Faculty of Veterinary Science, so he comes into regular contact with young students. “I think young people are much more aware now of the challenges that the natural world faces,” he says.

It might be expected that the veterinarian field is one of high burnout from stress, but Dr Bryant is a walking testimony to the benefits of doing a job you love. You wouldn’t expect someone on the frontline of extinction intervention to be so, well, eternally cheerful.

“I’m ever the optimist,” he says with a laugh. “I’m hoping that we might retrieve the Sumatran rhino from the brink of extinction by the application of ingenuity and science and our human genius for cooperation. I’m sitting here out on the grass on a beautiful Dubbo day and catastrophe seems very remote in this instance.”

Written By Jenny Valentish