The Tasmanian Devil: Brought Down by a Single Bite?
The Tasmanian devil is a resilient and notoriously fiendish predator. Weighing up to 26 pounds, this carnivorous marsupial may not seem like a threat. However, pound for pound, its muscular jaws and sharp teeth add up to one of the most powerful bites of any mammal. To this end, it is hard to believe that the species is facing a rapidly declining population – over 60% in the last decade.
Provided that humans have an exceedingly influential role in the ecosystem, it is surprising to find that human-induced climate change, water pollution or land development isn’t the culprit behind this population decline. Rather, cancer (a disease that also targets humans) is the disease that has taken this species by the thousands.
Specifically, this rare and highly parasitic cancer has been named the Devil Facial Tumor Disease (DFTD). Characterized by lesions on and around the mouth, these tumors have been known to spread from the face to the entire body within months. These tumors also interfere with feeding and lead to starvation – the primary cause of death.
Source: Australian Geographic, Getty Images
An illustration of DFTD in a Tasmanian Devil. Based on the size and texture of the tumor, it is easy to imagine how detrimental DFTD is to the survival of the Tasmanian Devil.
One of the reasons why DFTD is so transmissible is because of the devil’s behaviour: frequently biting each other’s faces while fighting for food or mates. Scientists studying the disease have also found that the cancer cells in these tumors shed, and take root in the wounds of bitten Tasmanian devils. Further analysis has shown that the tumors have a remarkably similar genetic makeup to Schwann cells (cells that cushion nerve fibers in the nervous system). For this reason, the Tasmanian devil’s immune system is unable to detect the cancer cell as a foreign cell, and will not take the necessary steps to mount an immune defense against the disease. As a result, DFTD is able to develop and proliferate throughout the entire body.
[youtube=https://www.youtube.com/watch?v=57jFF-pk_GA&w=640&h=385]
A video by Al Jazeera English (News Network) demonstrating the preliminary experimental method used to study DFTD. It also illustrates the physical features of DFTD in the Tasmanian devil.
Because the severity of DFTD has scientists predicting that the species could be lost within the next 25 years, it is commendable that humans are making great strides to prevent the extinction of the Tasmanian devil. Not only have scientists been able to receive grants to aid in DFTD research, but also, the Australian government has now listed Tasmanian devils as vulnerable and is drawing up captive breeding programs to save the species from extinction. To this end, we have simultaneously added to the existing knowledge of cancer as a multi-faceted tumor disease and are taking the steps to further study, isolate and find a vaccination. Ultimately, researching cancers in different mammals may help us find a cure in the future for cancers that plague the human race.
Further reading:
http://www.tassiedevil.com.au/tasdevil.nsf
October 21st, 2011 at 2:12 pm
Well, these are some ugly buggers. Although, I do find the way this disease is (brutally!) transmitted, I kinda question why were are intervening…
In geological time, millions of species have gone extinct and the world kept going just fine. I think extinction is a rather natural process. In fact without the extinction of certain species, there is NO WAY humans could have ever existed.
Sorry, I am getting on a bit of a tangent here. Very interesting article though!
October 21st, 2011 at 9:08 pm
I hadn’t heard about these poor little devils and I don’t think I knew there were parasitic cancers. That is terrifying. Do they have any thoughts on what might have caused the cancer in the first place?
October 28th, 2011 at 4:03 pm
I suppose that researching other forms of cancer could help us understand the different types of cancer plaguing the human race. Also, the way the cancer is spread is quite interesting – I would’ve never thought that cancer could become so contagious.
Scientists believe that the cancer arose from a single mutation in the Schwann cell which developed into a tumor (in one Tasmanian devil). As this infected Tasmanian devil continued to bite other Tasmanian devils while competing for food and mates, the disease was rapidly transmitted. Because the genetic variation of Tasmanian devils is limited, this could be the reason why the cancer has had such devastating effects.