THEY ARE CUTE, playful and feisty and firm favourites with visitors. But the four young Tasmanian devils at Taronga Zoo in Sydney, Australia, may also be the future of their kind.
Devils are succumbing to a contagious cancer on their island home of Tasmania. Deformities on their faces leave them dead within months, often from starvation. Since 1996 numbers have more than halved due to the devil facial tumour disease.
The situation is so dire that a captive insurance population has been set up in Australia, a Noah’s Ark in case the species goes extinct in the wild. Taronga Curator Paul Andrew says zoos are preparing to manage “Tassie Devils” in captivity for up to 50 years. The four females, born last April, are part of this insurance plan for saving what is the world’s largest marsupial carnivore.
Warner Brother’s crazy, ravenous cartoon character “Taz” didn’t help the animal’s public image. “Taz has given them a great profile but an undeserved reputation,” says devil keeper Tony Britt-Lewis.
They are a misunderstood animal, he says, shy and retiring by nature. Behind him, the four youngsters at Taronga scampered around their enclosure like puppies, playing tag and chase, growling and snorting all the while. The devil name likely came from such vocalisation, since early colonisers in Tasmania would have heard rather than seen these nocturnal creatures.
Young devils hunt more than the adults, catching insects and raiding bird’s nests, Andrew says. They climb trees and clamber along branches, their ears flashing red in the sun. They’ve a shuffling gait, something like bear cubs. Adult devils, which weight up to 11kg, are less mobile and often scavenge road kill, devouring whole carcasses in noisy groups. They have an incredibly powerful bite and can crunch through bone.
The deadly facial tumour is transmitted when devils bicker over carcasses or fight during the mating season. Our understanding is that even if resistance is found in the wild, it would be rapidly overwhelmed by the cancer’s rapid evolution, says Andrew. So far, there are 160 devils in the insurance population on mainland Australia. Forty joeys were born last year and a similar number should be born this year.
MARCH IS THE mating season and things look good so far. Andrew says two of their three females in Taronga appear to have mated successfully. Pregnancy lasts just three weeks, with pea-sized joeys born in April. Young stay in mother’s pouch for the first few months.
Steps are being taken to avoid adaptation to captivity. It was essential to bring as much genetic variability into the insurance population as possible, Andrew explains. This variation must then be maintained by breeding certain pairings. “We attempt to represent the founder’s equally,” he says.
“We retain the founder genes and allow their appropriate expression. When they go back into the wild, we want wild and very unco-operative animals.” The keepers interfere with devil behaviour as little as possible, he adds.
Andrew says it is difficult to see a reintroduction of devils to Tasmania while the cancer disease persists. “If we were seriously looking at the loss of the species, I think we would look at reintroduction to mainland Australia,” says Andrew. Devils lived on the mainland up until about 500 years ago.
A great deal more is known about “Tassie Devils” in the wild and about the deadly tumour in the lab, but there is little confidence a vaccine will emerge or useful resistance will evolve in the short term, says Andrew.
It is possible that the species may reach an accommodation with the disease, but this would leave the carnivore vulnerable to local extinctions in bad years. It would also further reduce their genetic variability. Andrew says: “Our feeling is that the insurance population is becoming more essential rather than less as time goes by.”
The young are often creched to reinforce devil behaviour. But their instinct is strong and keepers avoid putting their hands close to a devil’s mouth.
Britt-Lewis says each of the youngsters has its own personality; he calls the one with the biggest white marking Arrow. “She is the one most likely to nip us and the most boisterous and confident.” They are fed chicks, rabbit and raw egg and adults also get kangaroo tails.
The devils’ plight could inflict wider ecological damage. Tasmanians worry that non-native foxes could prosper in the wake of the devils’ difficulties. This could flatten the numbers of five small marsupials found only on Tasmania and make any reintroduction of devils all the more difficult.