Most people think of cancer as a private tragedy. It's something that happens inside a body when cells go rogue and refuse to die. It stays there. It doesn't jump from you to your neighbor. But in the late 1990s, a wildlife photographer named Christo Baars took a photo in northeast Tasmania that changed that rule forever. He saw a Tasmanian devil with a massive, grotesque swelling on its face. It looked like a one-off deformity. It wasn't. Within a decade, that single photo became the face of an extinction-level event called the Tasmanian devil facial tumour disease (DFTD).
It's a weird, terrifying reality.
Usually, the immune system is a brutal bouncer. It identifies "self" and "non-self" with ruthless efficiency. If I tried to give you a piece of my skin without a heavy cocktail of immunosuppressants, your body would reject it in days. But DFTD is a "transmissible cancer." It’s a living clone of a single female devil who lived at least 30 years ago. When devils fight—which they do constantly because they are incredibly cranky animals—they bite each other's faces. During those bites, living cancer cells are physically rubbed into the wound. Instead of the new host's immune system attacking the invader, the cancer takes root. It grows. It kills.
The Brutal Reality of DFTD in the Wild
The Tasmanian devil facial tumour is essentially a death sentence. Once the lumps appear around the mouth or neck, the animal is usually dead within six months. The tumours get so large that the devils can't eat. They starve to death while carrying around pounds of their own killer's flesh. It’s gruesome. Honestly, it’s one of the most harrowing things you’ll ever see in a nature documentary.
Since its discovery in 1996, the population has plummeted. Some areas have seen a 90% decline. Think about that. Imagine 9 out of 10 people in your city just vanishing. That’s the scale of the crisis in Tasmania.
The disease is a clone. Researchers like Elizabeth Murchison have spent years sequencing the genome of these tumours. What they found is fascinating and eerie. The DNA in a tumour found on a devil in the south of the island is almost identical to one found hundreds of miles north. It's the same individual's cells, surviving long after the original "patient zero" died. It is, in a very literal and dark way, a form of immortality.
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How the Devil Fights Back (and Why We Were Wrong)
For a long time, the outlook was bleak. Scientists thought the devils were doomed because they have very low genetic diversity. Basically, they're all "related" enough that their immune systems couldn't tell the difference between their own cells and the cancer cells. But nature is rarely that simple.
Recent studies, including work published in Nature Communications, suggest the devils are evolving. Fast.
In just a few generations—roughly 20 years—devils in some regions are showing genomic changes in areas related to immune function and cancer risk. They are learning to recognize the Tasmanian devil facial tumour as an enemy. Some devils have even been found with regressing tumours. They got the cancer, and then, miraculously, it went away. This was unthinkable ten years ago.
- Immune Adaptation: Some populations are developing a "hyper-active" immune response to recognize the low-diversity cells.
- Behavioral Shifts: There's evidence that some devils are becoming less aggressive or breeding earlier in life to ensure they pass on genes before the cancer catches up to them.
- Genetic Resilience: Specific markers in the devils' DNA are being selected for by the sheer pressure of the disease.
It’s a classic arms race. The cancer tries to hide; the devil tries to see it.
The Second Strain: DFT2
Just when we thought we had a handle on the situation, a second, completely independent transmissible cancer was discovered in 2014. It’s called DFT2. This is bad news. It means that the "clonally transmissible cancer" trick isn't a one-time fluke. It’s a strategy that can emerge more than once. DFT2 looks different under a microscope—it has different chromosomal arrangements—but it spreads the same way.
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This discovery sent shockwaves through the scientific community. It suggests that Tasmanian devils might be uniquely susceptible to this kind of pathology, perhaps due to their biting behavior and their specific genetic makeup.
What This Means for Human Cancer Research
You might wonder why we’re pouring so much money into saving a "screaming rat" on a tiny island. Beyond the ecological disaster of losing a top predator (which allows invasive cats and foxes to thrive), the Tasmanian devil facial tumour is a goldmine for human medicine.
Humans have a version of this, though it's rare. There are cases of "contagious" cancers in dogs (CTVT) and even some bivalves like clams. By studying how the devil's immune system eventually "learns" to fight a cloaked cancer, we might unlock new ways to teach human immune systems to find "invisible" tumours.
Immunotherapy is the frontier of modern oncology. The devils are providing a live-action laboratory for how a species survives a cancer that has learned to bypass the most basic laws of biology.
Current Conservation Efforts
We aren't just sitting back and watching them die. There are several massive projects underway:
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- The Insurance Population: This is a group of healthy, disease-free devils kept in zoos and on isolated islands like Maria Island. If the wild population hits zero, we can restart.
- Vaccine Research: Scientists at the Menzies Institute for Medical Research have been working on a vaccine. It's tough. You have to convince the immune system that these specific cells are "foreign."
- Wild Immunotherapy: There are trials where wild devils are captured, treated with immunotherapy agents, and released back into the wild to see if they can kick the infection.
It’s a massive logistical nightmare. Trapping devils across the rugged Tasmanian wilderness isn't for the faint of heart.
Why You Should Care About the Devil
If the devil goes extinct, the Tasmanian ecosystem collapses. The devil is a scavenger. They are the "clean-up crew." Without them, carcasses rot, disease spreads, and smaller predators like feral cats explode in number, wiping out native birds and small mammals.
But there’s a glimmer of hope. The most recent data suggests the decline is slowing. The "extinction" that was predicted for 2025 or 2030 hasn't happened. The devils are tougher than we gave them credit for. They are biting back, literally and genetically.
What You Can Do Next
Understanding the Tasmanian devil facial tumour isn't just about wildlife trivia. It’s about the future of biodiversity and medicine. If you want to actually make a difference or stay informed, here is how to move forward:
- Support the "Save the Tasmanian Devil Program" (STDP): This is the official government-led initiative. They coordinate the insurance populations and the field research that is actually keeping the species alive.
- Follow the Menzies Institute: Stay updated on their vaccine trials. Their work on DFT1 and DFT2 is at the absolute cutting edge of transmissible cancer research.
- Report Sightings if You're in Tasmania: Local "citizen science" is vital. If you see a devil with lumps—or even a healthy one—in an area where they’ve been scarce, that data helps map the disease's movement.
- Look into Comparative Oncology: If you are a student or researcher, look at how transmissible tumours in Tasmanian devils correlate with "immune evasion" in human small-cell lung cancers. There is more overlap than you’d think.
The situation is dire, but it’s not over. The Tasmanian devil is currently rewriting the rules of evolution in real-time. We just have to make sure we're there to read the final chapter.