Posts Tagged ‘Darwin’s fox’

guardian fail gray fox

I was just perusing the web for photos of a Darwin’s fox (which is a “false fox” from Chile and is probably the most endangered canid species in existence right now), and I cam across this image on The Guardian’s site.

The caption reads:

A Darwin’s fox (Pseudalopex fulvipes) at the Naha-Metzabok reserve, Mexico. Three new Mexican reserves were included in the list of the World Reserve Network of the Unesco Biosphere. The organisation included the Mexican reserves of Naha-Metzabok (State of Chiapas), Marias Islands (State of Nayarit) and Los Volcanes (which has the two highest mountains in the country, the Iztaccihualt and Popocatepetl)
Photograph: Moyses Zuniga/EPA

First of all, there are no Pseudalopex/Lycalopex canids in North America. If your name is Donald Trump, Mexico is in North America.

This animal is obviously the Urocyon, the primitive gray forest and brush dog that ranges from Southern Canada to Colombia and Venezuela. Although it is endemic to the Americas, it is not a Pseudalopex/Lycalopex. It’s it’s own weird little lineage.

Here is actually a good example of parallel evolution:

The Urocyon evolved in the humid forests of what is now South Central United States and the Darwin’s fox evolved in the temperate forests of Chile. They have sort of evolved similar morphologies through living in relatively similar habitats and having relatively similar niches. Dark gray color is also perfect camouflage in a forest habitat.

But the Urocyon is much more adaptable. It’s not even close to being endangered.

But we could very well lose the Darwin’s fox.

Here’s a real Darwin’s fox for comparison:

darwin's fox

I bet if the two species had be discovered at the same time, there would have been a debate as whether they were close relatives or not.

The Urocyon was known by the seventeenth century and fully documented by the end of the eighteenth, while the Darwin’s fox wasn’t even known until Darwin (yes, that Darwin) killed one with a geological hammer. But its exact species status wasn’t fully confirmed until the 1990s. There was a debate as to whether it was forest subspecies of the more common chilla.

So no, there are no Darwin’s foxes in Mexico, but it’s good to know that this Mexican Urocyon has a nice refuge to live out its life.

And seeing as the photo was taken in 2010, it’s probably already moved off this mortal coil.

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The red wolf controversy may be the best known of all canid taxonomy debates. Wolf taxonomy in general is quite contentious. Not only have “Eastern wolves” and “red wolves” been proposed as distinct species, some populations of the pallipes wolf in India and the some of the wolves of the Himalayas have, too. These two species were declared based upon mitchondrial DNA evidence. However, these animals are virtually indistinguishable from other pallipes wolves, which are the larger subspecies that is found from the Levant to the Indian subcontinent. It is likely a source for the domestic dog, and and the recent genome-wide study of wolf populations found that the Indian wolf fit within the Southwest Asian (SWA) group.

But wolves are unusually widespread and an unusually genetically diverse species. As a species, they are actually not endangered. They are merely endangered within certain parts of their range, and certain species, like the Mexican wolf, which has unjustly played second fiddle to the “red wolf” in North American wolf conservation circles, is quite endangered.

But what about a species whose range is confined only to a tiny archipelago and to an area that just happened to be declared a national park?

Such is the case of the Darwin’s fox (Lycalopex fulvipes) of Chile.

For decades its exact species status was highly contentious.

This fox is actually not a true fox at all. There are no true vulpine foxes in the whole of South America. What exists instead are various smaller canids that actually share closer evolutionary linkage to the true dogs in the genera Canis, Cuon, and Lycaon. Various genus names have been proposed for these “foxes,” including Pseudalopex, which means “false fox.” The current name is Lycalopex, which is a combination of the Greek words for wolf (“lycaon”) and fox (“alopex’). Literally, it means “wolf fox,” which is a much better reflection of their taxonomic status.

Everyone knew that the Darwin’s fox was one of these foxes, but whether it was a unique species or not was quite contentious.

Charles Darwin collected the first specimen in 1834, when he dispatched one on San Pedro Island in the Chiloé Archipelago.

He was able to make his kill by sneaking up on one and hitting it in the head with a geological hammer.

These foxes are quite opportunistic, and because they suffered very little predation on their island homeland, they became very unwary creatures. However, other species of South American “false fox” have these same traits; both the chilla (L. griseus) and the culpeo (L. culpaeus) have been known to beg for food from people in broad daylight. This trait was shared by the extinct Falkland Island’s wolf, which was thought to be one of these foxes, and one of the original genus names that was proposed for them was Dusicyon, meaning “foolish dog.” It’s very foolish to let an English seminary dropout sneak up on you and hit you with a hammer!

The scientific community eventually came to regard the Darwin’s fox as a subspecies the chilla. The chilla is sometimes called the South American gray fox, a name that should be dropped immediately for a very simple reason:  the Urocyon gray fox of North and Central America also ranges into Colombia and Venezuela. The Urocyon gray fox isn’t a true fox either, but it is quite different from both South American foxes. It represents a unique evolutionary lineage of wild dog that is not closely related to any other extant species— even though it looks very similar to the vulpine or true foxes. (Its only other living relative is the other “fox” in the genus Urocyon, the island fox of the California’s Channel Islands (U. littoralis).

One of the reasons why it was regarded as subspecies of the chilla is that it was believed to be found only on the Chiloé Archipelago. Island subspecies are often quite different from their mainland forms, and the darker colored fox on the islands was believed to be nothing more than a variation of the lighter gray chilla.

This darker coat led to the discrediting of the the possibility that this fox was the same as the Chilla.  In 1943, Wilfred Osgood thought the Darwin’s fox’s pelt was closer in terms of its color and characteristics to the Sechuran fox (L. sechurae) of the Peruvian and Ecuadorian deserts. In 1995, Christopher Yahnke confirmed this finding.

Around that same time, a dark colored population foxes that had been previous identified as chillas in Chile’s Nahuelbuta National Park on the Chilean mainland was determined to be the same thing as the Darwin’s foxes of the Chiloé. The fact that these two foxes were very similar suggested that the differences between the chilla and Darwin’s fox could not be ascribed to the peculiarities of unique insular evolution.

In 1996, Yahnke and Robert Wayne of UCLA compared mtDNA sequences from the Darwin’s foxes, the culpeos, and the chillas. It was instantly apparent that the mtDNA sequences of the Darwin’s fox were quite different from the chilla and the culpeo, which meant that the Darwin’s fox was truly a unique species after all.

The exact location of the Darwin’s fox within the dog family was not fully established until 2005, when the dog genomic sequence was released. Using SNP analysis, the researchers were able to reconstruct the entire dog family phylogenetic tree. The Darwin’s fox was found to be an older species than all of the Lycalopex species, except the hoary fox of Brazil.

Thus, Darwin’s fox is the oldest species of “fox” in the Southern Cone. It likely was once quite widespread in this region, but it evolved to live in the temperate forests that once dominated the landscape. These forests have disappeared, both through the forces of various periods of climate change and human deforestation, leaving only a relict population on the mainland. The Nahuelbuta population consists of only around 50 individuals, while the insular population is about 200-250 foxes, so these unique wild dogs are quite critically endangered.

The story of the Darwin’s fox tells us how important it is to get taxonomy right.

If we had continued to assume that the Darwin’s fox was nothing more than a dark chilla, then it could have become extinct without anyone understanding exactly what it was.

It reminds me very much of the situation that exists with wolves. Because so much of the paradigms of the conservation and scientific community have wrapped themselves into the red wolf and Eastern wolf hypotheses, valuable resources have gone into trying to preserve proposed species that may not be unique at all.

Those resources could have gone into Mexican wolf conservation– and Mexican wolf reintroduction has had many problems. Right now, the Mexican wolf recovery program is on the chopping block. It could probably use some of the money and personnel that has already been allocated to the red wolf recovery program, which is mostly concerned with trapping coyotes in red wolf range– to keep the red wolf pure! Of course, it’s now been revealed through a genome-wide analysis that the red wolf is actually a coyote with some wolf ancestry. It just has a bit more wolf in it than the typical Northeastern coyote. Coyotes are not endangered anywhere.

But because we got the taxonomy wrong, we have spent all of this time, money, and effort into conserving the red wolf, instead of the Mexican wolf. Granted, the politics for red wolf reintroduction was better. That part of Eastern North Carolina in which red wolves were released is not major cattle or sheep farming country, but the regions where Mexican wolves were reintroduced are. Further, the actual habitat chosen for Mexican wolf reintroduction wasn’t ideal wolf territory either– and it may have been outside the Mexican wolf’s historic range.

From this analysis, it is now obvious that we should have been much more worried about Mexican wolves than the so-called red wolf.

It would have been a shame if we had not examined the Darwin’s fox’s genetics. Pelage color and morphological analysis take one only so far.

But you can’t argue with DNA.

The Darwin’s fox is an ancient South American “wolf fox” that is native to the Southern Cone, and now it’s now restricted to a very narrow range. It is a living fossil of sorts, a claim that was once made about the red wolf.

But the Darwin’s fox is the real McCoy.

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Darwin's fox or Darwin's zorro

Darwin’s fox or Darwin’s zorro lives in the Chiloé Archipelago and Nahuelbuta National Park. It is considered critically endangered species that is adapted to the temperate rainforests of its Chilean homeland. It suffers from habitat loss, for the forests adjacent to the Nahuelbuta National Park are heavily logged. It is also persecuted because local farmers think the animal is a threat to their poultry. However endangered it is now, the Darwin’s fox was first documented through a specimen collected by Charles Darwin (which is why we call it the “Darwin’s fox.”)

Darwin describes his encounter with the unusual fox on San Pedro Island in the Chiloé Archipelago:

“In the evening we reached the island of San Pedro where we found the Beagle at anchor. In doubling the point, two of the officers landed to take a round of angles with the theodolite. A fox (Canis fulvipes), of a kind said to be peculiar to the island and very rare in it, and which is a new species, was sitting on the rocks. He was so intently absorbed in watching the work of the officers that I was able, by quietly walking up behind, to knock him on the head with a geological hammer. This fox, more curious or more scientific, but less wise than the generality of his brethren is now mounted in the museum of the Zoological Society.”

Charles Darwin The Voyage of the Beagle

Where wild dogs are not persecuted, they are often tame and curious animals. Indeed, the warrah or Falkland Island wolf was also quite tame and easily dispatched. Even wolves from North America, which had not yet suffered persecution by Westerners, were rather curious and unafraid of man. Lewis and Clark were able to kill at least one wolf by attracting it with a piece of meat and then stabbing it with a knife. You would never be able to do that to a wild wolf today, but historically, where they have not been persecuted, they are often curious animals. (There are no wolf populations today, however, that have no undergone at least some persecution, although those of the High Arctic are those that have experienced it the least.) That’s probably why hunter-gatherers were able to domesticate wolves so easily.

The Darwin’s fox is not a true fox of the genus Vulpes or its allies. (The Arctic fox and the fennec have not traditionally been seen as vulpine foxes, and are place in their own genera. However, the Arctic fox is very closely related to the swif fox, and the fennec is very closely related to the red fox and the Reuppell’s fox.) The Darwin’s fox and all South American foxes are not that closely related to these animals. Instead, they share a common ancestry with the true dogs, the genus Canis and its allies. All South American wild dogs are related to the true dogs, and because of this relationship, it is not exactly accurate to call any of the smaller animals “foxes.”

I prefer to call them zorros, which is Spanish for fox. Calling them zorros also prevents confusion in another way. The Darwin’s zorro’s closest relatives are the culpeo and the “South American gray fox.”  The latter has a terrible name.

Remember, there is another species called the gray fox. It’s a primitive wild dog that is native to North America. Some call it the North American gray fox, and that would be fine. However, its range extends through Mexico into Central America. There are populations of that animal in Colombia and Venezuela, which are South America. So are these also South American gray foxes?

I prefer to call the primitive animal the gray fox, even though it’s also not really a fox, and the South American animal the chilla fox or the gray zorro.

But things get even more confusing. At one time, the Darwin’s fox was considered a subspecies of the chilla. It was only when its DNA was compared with the chilla and the culpeo that it was declared a full species. Even today, one can find the Darwin’s fox listed as a subspecies of chilla in some taxonomic manuals and even peer-reviewed literature.

It is a very good book, if you’re into wild dogs.

And to make matters worse, the Darwin’s fox is in a lot of trouble. The areas around Nahuelbuta National Park are being clear cut. Settlers are moving into the lower valleys, and whenever the Chilean winter is harsh in those higher elevations, the foxes move down into settled areas, where they are often killed. So fully understanding that this species is a full species was very important.

If you would like to read more about Darwin’s fox, check out Holly Menino’s Darwin’s Fox and My Coyote. The book is about scientists studying three species of wild dog– the Darwin’s fox, the island fox (a relative the primitive gray fox), and the Eastern coyote. Two of these animals are endangered– the Darwin’s fox and the island fox. The coyote isn’t even remotely endangered, but it fits into the story because it is quite different in what we know about them. The scientists who are studying the two endangered species have to find out all sorts of information as quickly as possible. Species protection is riding on scientists’ ability to fnd out as much as they can about them. However, the process is long and tedious, and it’s very likely that while finding out as much as they can, the scientists will see their species disappear. The coyote scientists, however, are much more concerned with coming up with a management plan. Their animal isn’t endangered, and they have the leisure to come up with all sorts of more esoteric data about them.

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