Canis lupus hominis

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.