Saving the Devil

Jim McMahon/Mapman

Tasmanian devils have been the top predators on the Australian island of Tasmania for more than a century. But for the past 20 years, the furry, cat-size creatures have been the ones under attack. A contagious cancer has caused their population to plummet.

Unlike most cancers, this infectious cancer can spread between animals. Biting or other close contact transmits the disease, called devil facial tumor disease (DFTD), to another animal. The cancer causes tumors to grow rapidly on the devil’s face and neck. Eventually, it dies because it is unable to eat.

Tasmanian devils have been the top predators in their habitat for more than a century. They live on the Australian island of Tasmania. But for the past 20 years, the furry, cat-sized creatures have been under attack. A deadly type of cancer has caused the devil population to drop.

Most cancers infect one animal at a time. But this cancer can spread from devil to devil. A bite or other close contact transmits the cancer. The cancer is called devil facial tumor disease (DFTD). It causes tumors to grow on the devil’s face and neck. An infected devil dies because it can’t eat.

Many people thought DFTD was a death sentence for the infected animals. By 2011, the disease had wiped out more than 80 percent of wild devils. “The sheer number of animals that don’t survive is overwhelming,” says David Pemberton. He’s the manager of the Save the Tasmanian Devil Program.

But now, there are signs that some devils are undergoing rapid evolution to beat DFTD. Changes have been occurring in the devils’ life cycles and genes that could help them survive.

One of the reasons DFTD is so devastating is that it kills devils in their reproductive years. That’s when they would usually be having babies, called joeys. But scientists have found that some devils are now starting to reproduce earlier in life. This means the devils are able to have joeys before they succumb to the disease.

Many people thought DFTD was unstoppable. By 2011, it had wiped out more than 80 percent of wild devils. “The number of animals that don’t survive is overwhelming,” says David Pemberton. He’s the manager of the Save the Tasmanian Devil Program.

But now, there are signs that some devils might be able to beat DFTD. Changes are happening in the devils’ biology that could help them survive.

One of the reasons DFTD is so bad is that it kills devils before they can reproduce. But now some devils are having babies earlier. This means the devils reproduce before dying of DFTD.

Some lucky devils have also developed resistance to the disease. Scientists are now using them in a captive-breeding program called the Devil Ark. The program managers hope that these devils will pass on their DFTD-resistant genes to their joeys. When they’re old enough, the captive-raised devils will be released in places where existing populations are very small but healthy. Adding disease-resistant devils to the wild population increases the likelihood that the devils will live long enough to spread their genes. The hope is that future generations will be able to beat DFTD.

“We have had a record number of joeys so far this year, and it makes all the hard work pay off,” says Abram Tompkins, a keeper with Devil Ark.

Some lucky devils are now resistant to DFTD. This means they won't catch the disease. Scientists are raising these devils in a breeding program called the Devil Ark. They hope the devils will pass the resistance on to their babies. Once they are old enough the babies will be released in places across Tasmania. The disease-resistant devils will then have a chance of passing on their resistance in the wild. Scientists hope future generations will be able to survive DFTD.

Now, there’s good news for the devils. A record number of babies were born this year at the Devil Ark. "It makes all the hard work pay off,” says Abram Tompkins, a keeper with Devil Ark.

Devil Ark has been breeding DFTD-free devils on Maria Island, which is off the southeastern coast of Tasmania. Use this information to answer the following questions about the breeding program. Round all answers to the nearest whole number. Record your work and answers on our answer sheet.

The Maria Island breeding program started in 2012, when Devil Ark released 15 devils. About 13% of them have died. How many is that?

In early 2016, there were about 80 devils living on Maria Island. Of that total, 75% are offspring from the previous two breeding seasons. How many are offspring?

In May 2017, about 105 devils lived on Maria Island. Of those, 31% were captured and released into the wild to help struggling populations. How many is that?