Doing the devil’s work

Finally, hearts thumping, they tipped their first south-western devil out of the trap: a hefty, healthy older male, with a thick coat and excellent teeth. Best of all, his face was clear and clean — he was cancer-free.

After months of planning, the hunt in Tasmania’s remote southwest wilderness was in motion. Rigorously detailed to the last ­satellite phone and devil trap, it encompassed helicopter trips ending with wind-blown beach landings, 1400kg of gear, 100kg of ­frozen and vacuum-packed wallaby meat for devil bait, extreme camping with freeze-dried meals, and two teams of dedicated devil-trappers — most with an almost ­encyclopaedic knowledge of the small Australian carnivore known as the Tasmanian devil.

One team was choppered in to Wreck Bay, on the coastal edge of the internationally famed Tasmanian Wilderness World Heritage area and about 50km from the nearest road or ­building. The other was flown to Nye Bay, about 18km north. The helicopter hauled their gear in 700kg sling-loads, one for each team. Wild, untrodden beaches; crashing waves, blowing sand, a strip of coastal bush backed by vast stretches of low, shrubby, button-grass plain — it wasn’t easy country.

Carolyn Hogg with a Tasmanian devil. Picture: Drew Lee / Save the Tasmanian Devil program
Carolyn Hogg with a Tasmanian devil. Picture: Drew Lee / Save the Tasmanian Devil program

Nobody knew healthy populations of devils were living in this remote corner of Tasmania until this ­expedition found them. Dr Carolyn Hogg, research manager of Australasian Wildlife Genomics Group at the University of ­Sydney, remembers the hard work and the elation of discovery. One of the Nye Bay team, she and her colleagues trudged a 10km trap-line for days in rain and sun. “It was hard work, walking all day in the sand,” she says. “But you’ve got to imagine, it’s pretty spectacular to be down in this amazing, wild countryside with the wind blowing and the sand blasting into your face. Some days it was sunny and warm, and other days it was bitterly cold with rain. Every day you’re out in it.”

The Wreck Bay team caught their first devil pretty quickly — the big old male. But for Hogg and the Nye Bay team, the devils were more elusive. Days passed. Sand. Rain. Sun. Finally, Hogg and a friend went out to walk the trap-line again, hoping for a devil, hoping for new blood for this teetering Australian ­species, this little critically endangered meat-eater. “It took us a long time to get our first devil,” she says, pausing to remember the moment. “Then one day we went out and the first four traps all had devils in them.”

Largely nocturnal, the southwest devils patrol the beaches for carrion — dead fish, seals or even whales, and roam inland on the strip of coastal rainforest between the sand and the button-grass plains for possums or wallabies. Mostly ­scavengers, they will kill and eat prey if they can.

Once ranging across the continent, devils — the world’s largest carnivorous marsupial — are now found only in the wild in Tasmania and a terrible and transmissible facial cancer has decimated the population. The disease was first documented in Tasmania’s far northeast in 1996, and since then it has moved slowly but inexorably south and west. It’s now thought to cover 80 per cent of the state.

Tasmanian devils are now so genetically similar that they can pass on this clonal cancer via cells when they fight or mate. A tiny pocket of ­animals remains disease-free on Woolnorth Farm on Tasmania’s northwest tip, but the experts know it’s only a matter of time — maybe two or three years — before the creeping tide of the cancer reaches there. The disease (devil facial tumour disease, DFTD), which leaves devils with frightening tumours bulging from their mouths and faces, has already wiped out nearly 80 per cent of wild devils. Yet small populations persist, breeding younger, with bigger litters. Before the cancer began its rampage, devil females usually mated and had litters of young at age two or even older; now they’re breeding when they are only a year old — a standard response when populations decrease dramatically.

The cancer is killing off all the older devils with weaker immune systems — the three, four and five-year-olds — and playing havoc with the population’s prospects. Diseased devil populations now consist of mostly one-year-olds and a few two-year-olds. An “insurance population” of 700 or so healthy devils now lives in 42 zoos and ­sanctuaries across Australia, on Maria Island off Tasmania’s east coast, and on the fenced Forestier Peninsula near Hobart. One ongoing strategy is to bolster diseased populations with regular releases of healthy devils from this insurance population.

At the same time, large numbers of devils are killed by speeding cars and trucks — although that carnage has been mitigated slightly by the introduction of the “virtual fence”, an alarm system installed at roadkill hotspots after a trial was conducted in the state’s northwest in 2014. Triggered by a car’s headlights, it uses sound and light to warn devils away from the road. Tasmanian devils also have to compete with feral cats, which are now spread across Tasmania, even in the remote southwest World Heritage Area.

With all these stresses, a natural disaster — say a big flood or a bushfire — could tip this fragile ­species over the edge to join Australia’s long and dismal list of mammal extinctions. So when a bushwalker and biologist found a handful of scat (poop in layman’s language) in Tasmania’s rugged southwest in 2015, she sent it to the University of Sydney for testing to determine whether it was a devil’s scat. When it tested positive, hopes began to build: this handful of scat could be the harbinger of a new and much-needed bloodline.

World Heritage volunteers were roped in for the ambitious project. Usually dedicated to weed removal and fauna surveys, they were given ­photos of devil scat and “poo packs” to collect it in. By 2016 the University of Sydney had 113 scat samples; 85 were found to be devil scat. Optimism began to take hold, but questions needed to be answered. “We knew devils were there,” Hogg says. “But did they have the disease?” There was evidence the cancer had reached Lake Pedder, about 40km from Wreck Bay and Nye Bay, but a mountain range and vast stretches of button-grass plain and rainforest were thought to provide a natural barrier for the coastal devils.

The estimated cost of a properly financed week-long trip to catch, weigh, assess and take biopsies from a sufficient number of devils was at least $25,000. A crowd-funding campaign drew donations from 106 donors; from individuals, from a Year 2 cake sale (after Hogg had visited a primary school, armed with a devil skull and sack, to give one of her wildly popular volunteer science talks) and from Toledo Zoo & Aquarium in the US, which has a longstanding partnership with the Save the Tasmanian Devil program. (Toledo also sent a zookeeper and a professional photographer- cinematographer.) In the end, the campaign raised $37,000. Planning began in earnest.

Samantha Fox sets a trap at Wreck Bay. Picture: Corey Wickoff / Toledo Zoo & Aquarium.
Samantha Fox sets a trap at Wreck Bay. Picture: Corey Wickoff / Toledo Zoo & Aquarium.

For Samantha Fox, from the Wreck Bay team, all the effort was worth it when she got hold of her first southwest devil, sliding him out of the polypipe trap and into the waiting sack. “The first devil we caught was this big old male. I reckon he was at least five years old and he was in immaculate condition,” she remembers. “He had amazing teeth. It was probably the most exciting part of the trip, that first devil. You would never see a five-year-old devil in a diseased population.”

Fox, a Save the Tasmanian Devil Program team leader, has been working with devils since 2008. They’re fascinating creatures, she says, and the ongoing war between host and disease, and the evolution of the two, make devil research a magnetic field of study.

Despite the hardships, the southwest expedition was a joy. “It was very wild, very raw, and a remarkably stunning area. You walk out of coastal rainforest and on to button-grass plains. It was pretty tough going.” She says everyone got ­fitter, and probably slimmer, from the energy expenditure and endless freeze-dried meals, punctuated by a memorable meal of fresh fish caught by a team member. “It was extreme camping,” Fox says. “You take in only what you need, and if you’ve ­forgotten it, well it’s tough.”

Mary Beth of Save the Tasmanian Devil program at Wreck Bay. Picture: Corey Wickoff / Toledo Zoo & Aquarium
Mary Beth of Save the Tasmanian Devil program at Wreck Bay. Picture: Corey Wickoff / Toledo Zoo & Aquarium

The expedition lasted the planned seven days and by the end of it the Wreck Bay team had trapped eight devils and the Nye Bay team six. All were healthy and free of the facial cancer.

Save the Tasmanian Devil Program manager David Pemberton says the existence of these healthy devils is “very comforting” as he expects they will provide some of the genetic diversity the ­species desperately needs. If they are sufficiently different he is ready to put forward “the case for extraction” of one or two females. They would then be bred to spread their genes into the insurance populations and, in time, across the rest of Tasmania.

For the moment, Pemberton says, efforts are centred on managing a “depleted but persisting” population of devils in Tasmania, which is a far more difficult task than starting again. If devils did become extinct in the wild, he says, healthy individuals from the insurance populations could be reintroduced and the cancer would be eliminated.

About a decade ago, Pemberton found healthy devils at Discovery Beach, about 60km north of the latest discovery site. But they haven’t been assessed since, so nobody knows whether the ­cancer has reached them. There are only seven transmissible cancers in the world, he says ruefully, and Tasmania has two of them (variants of the facial clonal cancer). Other cancers of this kind are found mostly in shellfish.

Geneticist Katherine Belov, professor of ­comparative genomics in the School of Life and Environmental Sciences at the University of ­Sydney, says that although mutations and adap­tations will gradually expand a population’s gene pool, it takes an incredibly long time. New devil bloodlines from new populations can short-­circuit that process and help the ­devils regain a surer footing. Devils have a tiny gene pool, she adds, far smaller than koalas, wallabies and kangaroos. They’re right down there with cheetahs. “If you have really low genetic diversity, issues of disease become much more prevalent,” she says. “The ability to adapt and change is lower, and the ­species is much more prone to extinction. When species reach this stage, they’re entering an ‘extinction vortex’ and some unusual event could push them over the edge.”

Belov and her colleagues will sequence parts of the southwest devils’ genomes — and, if the ­findings prove promising, whole genomes — to determine the levels of genetic difference in this precious cluster. And hopes for the beleaguered little carnivore will begin to build again.