How Tasmanian devils are evolving to fight back against extinction
Devil facial tumor disease, or DFTD, has cut the Tasmanian devil population by 90 percent. Now, some devils have evolved to resist the virulent cancer.
- Devil facial tumor disease, or DFTD, is a transmissible cancer that Tasmanian devils spread through bites.
- The cancer is highly infectious and lethal, and the Tasmanian devil population has dropped by 90 percent since it was first discovered.
- In the short time that we've known about the disease, however, the devils seem to be evolving new defenses that are helping some of them fight back and survive.
In 1996, Dutch photographer Christo Baars was looking through the images he had captured from a recent trip to northeastern Tasmania. His subject was the famously scrappy Tasmanian devil. But the devil in his pictures looked to be in bad shape, and not just because of the scars devils often accumulate when fighting one another. They had bulbous growths covering their faces.
Baars showed his photographs to a wildlife officer in Tasmanian Parks and Wildlife. This marked the beginning of humanity's awareness of the strange disease that had begun to inflict the Tasmanian devils, one that would ultimately cut their population down by 90 percent. Years later in 2007, it was predicted that the entire species would be extinct within 35 years.
This was bad news for Tasmania as a whole. Devils are what's known as a keystone species, a species with outsized importance on the local ecosystem. Like many islands, Tasmania possesses exceptionally unique flora and fauna, and its ecosystem is particularly sensitive. So, it was crucial to preserve the devil population, but the unique nature of the disease made this a challenging task.
Devil facial tumor disease, or DFTD, is an exceedingly common in the devil population, but it's actually an incredibly rare form of cancer. Specifically, DFTD is a transmissible cancer. Almost all cancers arise from within as a result of a cellular mutation, but DFTD comes from without, a kind of parasitic cancer.
Transmissible cancers are known to occur in only a handful of other animals, notably dogs, Syrian hamsters, and soft-shell clams. In devils, the cancer is spread through bites, a particularly efficient means of transmission for this species. What's more, when researchers examined cancerous cells from different devils, the cancers were genetically identical, suggesting that the cancer started with one individual and then spread from devil to devil. In a sense, it's less accurate to describe Tasmanian devils as each having their own cancer; instead, all infected devils have the same cancer.
Another lethal aspect of DFTD has to do with the small size of the Tasmanian ecosystem. Without much room for their population to grow and become diverse, Tasmanian devils are all quite similar genetically. As such, when the first devil to be infected with DFTD spread his or her cancer cells to other devils, their immune systems failed to recognize the foreign cells as foreign — the DFTD cells weren't being attacked and suppressed as would have happened if, say, the devils had been infected by a virus.
A glimmer of hope
A Tasmanian devil is seen in a trap after being captured in the wild to check for signs of DFTD. Photo credit: Adam Pretty / Getty Images
Since DFTD is a cancer, its nearly impossible to treat in wild animals — without opposable thumbs to mark off their calendars, Tasmanian devils have had trouble making their chemotherapy appointments. Some researchers have been working hard at crafting a cancer vaccine that, when injected, could prompt the devils' immune systems to attack the debilitating tumors.
However, it seems like the devils are bouncing back without little help from humans at all. Dr. Rodrigo Hamede from the University of Tasmania has been monitoring DFTD and Tasmanian devils for years now. "Natural selection is trying to fix the problem on its own by favoring those who can survive the tumor, so we're more hopeful these days than ever before," said Hamede to the BBC. "We have witnessed how these tumors shape the ecology of devils and how they have been evolving with their hosts in real time."
Remarkably, in just 16 years — eight generations for Tasmanian devils — the devils have evolved to resist DFTD. Usually, DFTD kills devils within a year or slightly longer by making it difficult for them to eat or through metastases. However, Hamede's team has found some devils that have survived for two years with DFTD, enabling them to reproduce more frequently and give birth to young resistant to the disease. Even better, the team has recorded 23 cases of tumor regression, implying that some devils may be better equipped to fight against and recover from DFTD.
Taking these and other factors into account, Hamede's team conducted a forecast of the likely outcomes for the Tasmanian devil population based on the available data. Over the next 100 years, the researchers estimated that there was a 21 percent chance the Tasmanian devil would go extinct, a 22 percent chance the devils would coexist with DFTD, and a 57 percent chance that the debilitating cancer would fade out of existence.While this is all extremely encouraging, the Tasmanian devils aren't out of the woods yet. To ensure the survival of the species, a small population of cancer-free devils have been brought to Maria Island, just three miles off the coast of Tasmania, which has no native population of Tasmanian devils. The same has been done in a facility in Hobart, the capital of the Tasmanian island state. No matter whether the devils or their cancer wins out the fight, with any luck, the species will survive.
- Parks & Wildlife Service - Tasmanian Devil ›
- Save the Tasmanian Devil Program ›
- Tasmanian Devil | National Geographic ›
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- Eventually, scientists hope to print patient-specific organs that can be transplanted safely into the human body.
- Northwell Health, New York State's largest health care provider, is pioneering 3D printing in medicine in three key ways.
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Is this proof of a dramatic shift?
- Map details dramatic shift from CNN to Fox News over 10-year period
- Does it show the triumph of "fake news" — or, rather, its defeat?
- A closer look at the map's legend allows for more complex analyses
Dramatic and misleading
Image: Reddit / SICResearch
The situation today: CNN pushed back to the edges of the country.
Over the course of no more than a decade, America has radically switched favorites when it comes to cable news networks. As this sequence of maps showing TMAs (Television Market Areas) suggests, CNN is out, Fox News is in.
The maps are certainly dramatic, but also a bit misleading. They nevertheless provide some insight into the state of journalism and the public's attitudes toward the press in the US.
Let's zoom in:
- It's 2008, on the eve of the Obama Era. CNN (blue) dominates the cable news landscape across America. Fox News (red) is an upstart (°1996) with a few regional bastions in the South.
- By 2010, Fox News has broken out of its southern heartland, colonizing markets in the Midwest and the Northwest — and even northern Maine and southern Alaska.
- Two years later, Fox News has lost those two outliers, but has filled up in the middle: it now boasts two large, contiguous blocks in the southeast and northwest, almost touching.
- In 2014, Fox News seems past its prime. The northwestern block has shrunk, the southeastern one has fragmented.
- Energised by Trump's 2016 presidential campaign, Fox News is back with a vengeance. Not only have Maine and Alaska gone from entirely blue to entirely red, so has most of the rest of the U.S. Fox News has plugged the Nebraska Gap: it's no longer possible to walk from coast to coast across CNN territory.
- By 2018, the fortunes from a decade earlier have almost reversed. Fox News rules the roost. CNN clings on to the Pacific Coast, New Mexico, Minnesota and parts of the Northeast — plus a smattering of metropolitan areas in the South and Midwest.
Image source: Reddit / SICResearch
This sequence of maps, showing America turning from blue to red, elicited strong reactions on the Reddit forum where it was published last week. For some, the takeover by Fox News illustrates the demise of all that's good and fair about news journalism. Among the comments?
- "The end is near."
- "The idiocracy grows."
- "(It's) like a spreading disease."
- "One of the more frightening maps I've seen."
- "LOL that's what happens when you're fake news!"
- "CNN went down the toilet on quality."
- "A Minecraft YouTuber could beat CNN's numbers."
- "CNN has become more like a high-school production of a news show."
Not a few find fault with both channels, even if not always to the same degree:
- "That anybody considers either of those networks good news sources is troubling."
- "Both leave you understanding less rather than more."
- "This is what happens when you spout bullsh-- for two years straight. People find an alternative — even if it's just different bullsh--."
- "CNN is sh-- but it's nowhere close to the outright bullsh-- and baseless propaganda Fox News spews."
"Old people learning to Google"
Image: Google Trends
CNN vs. Fox News search terms (200!-2018)
But what do the maps actually show? Created by SICResearch, they do show a huge evolution, but not of both cable news networks' audience size (i.e. Nielsen ratings). The dramatic shift is one in Google search trends. In other words, it shows how often people type in "CNN" or "Fox News" when surfing the web. And that does not necessarily reflect the relative popularity of both networks. As some commenters suggest:
- "I can't remember the last time that I've searched for a news channel on Google. Is it really that difficult for people to type 'cnn.com'?"
- "More than anything else, these maps show smart phone proliferation (among older people) more than anything else."
- "This is a map of how old people and rural areas have learned to use Google in the last decade."
- "This is basically a map of people who don't understand how the internet works, and it's no surprise that it leans conservative."
A visual image as strong as this map sequence looks designed to elicit a vehement response — and its lack of context offers viewers little new information to challenge their preconceptions. Like the news itself, cartography pretends to be objective, but always has an agenda of its own, even if just by the selection of its topics.
The trick is not to despair of maps (or news) but to get a good sense of the parameters that are in play. And, as is often the case (with both maps and news), what's left out is at least as significant as what's actually shown.
One important point: while Fox News is the sole major purveyor of news and opinion with a conservative/right-wing slant, CNN has more competition in the center/left part of the spectrum, notably from MSNBC.
Another: the average age of cable news viewers — whether they watch CNN or Fox News — is in the mid-60s. As a result of a shift in generational habits, TV viewing is down across the board. Younger people are more comfortable with a "cafeteria" approach to their news menu, selecting alternative and online sources for their information.
It should also be noted, however, that Fox News, according to Harvard's Nieman Lab, dominates Facebook when it comes to engagement among news outlets.
CNN, Fox and MSNBC
Image: Google Trends
CNN vs. Fox (without the 'News'; may include searches for actual foxes). See MSNBC (in yellow) for comparison
For the record, here are the Nielsen ratings for average daily viewer total for the three main cable news networks, for 2018 (compared to 2017):
- Fox News: 1,425,000 (-5%)
- MSNBC: 994,000 (+12%)
- CNN: 706,000 (-9%)
And according to this recent overview, the top 50 of the most popular websites in the U.S. includes cnn.com in 28th place, and foxnews.com in... 27th place.The top 5, in descending order, consists of google.com, youtube.com, facebook.com, amazon.com and yahoo.com — the latter being the highest-placed website in the News and Media category.
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