By: Joshua Hobbs
The Tasmanian devil. A marsupial that cannot be mistaken for any other. What comes to mind when you think of the Tasmanian devil? Is it its spine chilling screeches? Or perhaps it is its dark black fur combined with sharp teeth? Or maybe it is its famous bad temper that made it be dubbed “The Devil”? Or, more likely than not, you might be flooded with childhood memories of early mornings watching Bugs Bunny and company trying their best to save themselves from being devoured to shreds by the infamous Taz, who was always ready to eat any and everything as long as the opportunity presented itself. While these are the things that usually come to people’s minds when they think of this very polarizing creature, the current reality is something that is somewhat surprising.
https://www.flickr.com/photos/54919275@N08/8446644201/sizes/l/ By David Taylor is licensed under CC 2.0.
First, here is a little background about the Tasmanian devil. They are the largest surviving carnivorous marsupial, and are found on the island of Tasmania. Once very populous on the actual mainland of Australia, the devil became extinct on the mainland some 400 years ago before European settlement most likely due to the spread of dingoes in the surrounding land. Characterized by their squat build, broad head, and short, thick tail, this animal is widely known for its muscular build and ferocity when feeding (3).
If they are these masculine, ferocious, dominant creatures that we all think and know that they are, then what exactly is the current problem? Wouldn’t you think that these creatures not have any difficulties surviving regardless of the adversity that they face?
Well, things are rarely as simple as they seem. A big problem for the current Tasmanian devils first arose in 1996. They began to appear in Mount William in northeastern Tasmania with apparent facial tumors that led to infected individuals to die within months of the onset. The disease, unfortunately, is transmissible, which basically means that it is contagious and can be transmitted to other animals. Crazy right? Well it is especially worse for the Tasmanian devil, as the current population has extremely low levels of genetic diversity, making the disease more transmissible. This has led to 20 to 80 percent of the current population in Tasmania to become impacted, leading to 65 percent of the whole island of Tasmania being infected (2). Only the state’s west and north-west areas are unaffected.
What does this mean for the outlook of the Tasmanian devil population? Well as of 2008, it has been estimated that only 10,000 to 15,000 individuals are left in the wild. This has led to the change of the Tasmanian devil being classified as lower risk/least concern in 1996, to endangered as of 2008 by The IUCN Red List of Threatened Species. This is a huge change in a species that in a span of 15 years has gone from an animal that had little to no concerns for its population, to risk of becoming extinct (3).
But there definitely is a light at the end of the tunnel. Some populations of devils have done better than disease models have predicted. This finding has perplexed scientists around the world as they wondered what could have possibly caused this. Menna Jones and her colleagues at the University of Tasmania to study the population of 300 devils in 3 separate regions of Tasmania from before and after the onset of the disease in the area. In two of the three regions that were studied, the populations of the devils from before the onset of the disease to after are different; in both of these regions, immunity and cancer being linked to both of these regions. The authors of the study predicted that resistance spread throughout the population in 4 to 6 generations, much faster than initially expected; “It’s as if extreme mortality has led to extreme evolutionary selection pressure,” says Jones. “It has happened a lot faster than we expected.” The findings show that species can in fact evolve in less than 10 generations when presented with a lethal threat to its population (1).
While it is very hopeful for the Tasmanian devil population, scientists have been proactive in their efforts as well in helping the current Tasmanian devil population from contracting the disease. Recently 33 immunized devils have been released into the wild in an effort for them to mix with the unimmunized population.
Why should we care? Devils are very dangerous creatures that might potentially harm us or the animals we own, right? Many critics of the marsupial believe that the earth might possibly be in a better place if they went extinct. There is a big misconception that the devil causes copious amounts of harm to the environment and its inhabitants. Despite the negative connotation given to the devil, they usually remain still and calm while in the presence of humans, even sometimes shaking due to nervousness. That does not seem like a blood-thirsty creature now does it? Additionally, there has been evidence by scientists that any concerns over devils damaging livestock have been greatly over exaggerated. The majority of negative conations that are attributed to the Tasmanian devil are in one way or another distorted.
The Tasmanian devil population has been in in trouble recently due to many factors that have affected the population. Despite these factors, the devil population has been able to show resistance against its biggest threat in the Devil Facial Tumor Disease (DFTD). While this is good news, we as humans have to remember our role in their waning populations as well. With this in mind with the evolution of the Tasmanian devil, the population may in fact be able to be saved after all.
- Klein, Alice, 2 Sept. 2016. Superfast Evolution Could Save Tasmanian Devils from Extinction. New Scientist Magazine.
- Murchison EP, et al. (2010) The Tasmanian devil transcriptome reveals Schwann cell origins of a clonally transmissible cancer. Science 327(5961):84–87.
- Pye, R. J. et al.A second transmissible cancer in Tasmanian devils.Proc. Natl Acad. Sci. USA113, 374–379 (2016).