| Darwin's fox[1] | |
|---|---|
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Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Carnivora |
| Family: | Canidae |
| Genus: | Lycalopex |
| Species: | L. fulvipes |
| Binomial name | |
| Lycalopex fulvipes (Martin, 1837) | |
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| Darwin's fox range[contradictory] | |
| Synonyms | |
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Darwin's fox orDarwin's zorro (Lycalopex fulvipes) is anendangeredcanid from the genusLycalopex. It is also known as thezorro chilote orzorro de Darwin[2] inSpanish and lives inNahuelbuta National Park, theCordillera de Oncol,Cordillera Pelada in mainlandChile andChiloé Island.[4] This small, dark canine weighs 1.8 to 3.95 kg (4.0 to 8.7 lb), has a head-and-body length of 48 to 59 cm (19 to 23 in) and a tail that is 17.5 to 25.5 cm (7 to 10 in).[5] Darwin's fox displays no key differences between male and female other than the fact that the male has a broadermuzzle.[6] Males display no territorial behavior and are not aggressive towards other males roaming around their territory.[6]
Darwin's fox was first collected fromSan Pedro Island off the coast of Chile by the naturalistCharles Darwin, in 1834, hence, the name- Darwin's Fox. It was long held that Darwin's fox was a subspecies of theSouth American gray fox (L. griseus); however, the discovery of a small population of Darwin's fox on the mainland inNahuelbuta National Park, in 1990[7] and subsequent genetic analysis has clarified the fox's status as a unique species.[8] In 2012 and 2013, the presence of the Darwin's fox atOncol Park,Alerce Costero National Park and theValdivian Coastal Reserve was confirmed through camera trapping.[4]
Lycalopex is aSouth American genus of canine, which is distantly related to wolves and is technically not afox. When Charles Darwin collected a specimen from San Pedro Island inChiloé Archipelago in December, 1834, during theBeagle survey expedition, he observed that this "fox (of Chiloe, a rare animal) sat on the point & was so absorbed in watching [survey work], that he allowed me to walk behind him & actually kill him with mygeological hammer."[9] In the 1839, publication of hisJournal and Remarks, Darwin said "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." He said it was "an undescribed species,"[10] indicating that it was distinct from the species (L. culpaeus andL. griseus) that occur on the mainland. Later, Darwin's fox was classified as a subspecies (Lycalopex griseus fulvipes) of the latter.
Darwin's fox does notinterbreed with the otherLycalopex species, only lives in forests, and is smaller and darker-colored than the other species. In 1990, a small population of Darwin's fox was found on the mainland in the forested Nahuelbuta National Park, indicating that the fox was not endemic to the island. According to Yahnke et al., in their 1996 article, published in the Journal of the Society for Conservation Biology, analysis of mitochondrial DNA of Darwin's fox and the gray fox showed two patterns, indicating Darwin's fox was a new species, closely related to theSechuran fox. Also according to Yahnke (1995; et al.1996) the present restricted range is a relic of a much wider former range. Zoologists noted the distinctiveness in the ecological niche, appearance, and behavior of this species. Darwin's fox is differentiated from thegray fox in being darker; having shorter legs; a broader, shorter skull; smaller auditory bullae; a more robust dentition; and a different jaw shape and style of premolar occlusion.[citation needed]
In the latePleistocene, Chiloé Island was connected to mainland Chile by a land bridge. The land bridge was severed about 15,000 years ago when the sea level rose following the last glaciation.[11] This created two isolated populations of Darwin's fox.[citation needed]
Darwin's fox has a vast diet. In dense forests, where it exists, the foxes hunt for mammals,reptiles,beetles, andinvertebrates. Sometimes it selectsfruits,berries, andseeds.[12]Birds andamphibians to a lesser degree are also consumed. It sometimes eats carrion, but it mostly eats live animals and fruit. This makes it mostly an omnivore, sometimes a scavenger.[citation needed]
Darwin's fox is generally believed to be a forest obligate species found only insouthern temperate rainforests.[2] They only occur in areas of primary forest on Chiloé and on the mainland. They are most active at twilight and before sunrise. In contrast to otherLycalopex species, Darwin's fox prefers open spaces. The population of Chiloé has about 200 individuals, and Nahuelbuta on the mainland contains about 50 individuals. The total population size is about 250 mature individuals with at least 90% of the population occurring in one subpopulation (Chiloé Island). Although the species is protected in Nahuelbuta National Park, substantial mortality sources exist when foxes move to lower, unprotected private areas in search of milder conditions during the winter.[13] The population was considered as critically endangered because its main population occurred in one island and their habitat was declining due to human impact.[14]
The species was previously classified asCritically Endangered by theIUCN, but in 2016 was downlisted toEndangered, as its area occurrences is apparently substantially larger than originally believed. Current estimates of the total population are still low, with an estimated minimum 227 individuals on the mainland and 412 on Chiloé Island. Fragmentation of forest adjacent to the national park and on the island is a concern for their conservation, and feral dogs may pose the greatest threat to their survival by spreading disease or directly attacking. Persecution by people who think that the foxes attack domestic fowls, though they pose little threat, is also a potential problem.[2]
The species is often plagued byMycoplasma haemocanis. The already endangered fox is prone to thisinfection because the infection's bacteria attach themselves to surface red blood cells of many mammals, and although the species is believed to be no major threat to human life it can spread to humans, dogs, cats, and other wildlife species. The bacteria also seem to spike when located close to any major habitat inhabited by humans as well as where there is a large population of wild dogs present near the species. Researchers are testing RNA subunits of RNase P gene and out of 10 foxes, nine were infected. Even though they are considered "sick", they have no external symptoms (Cabello, 2013). Studies show that many foxes risk of catching the deadly bacteria inclines as they age leaving many older foxes vulnerable. Although the disease is prevalent in this species, little to nothing is known about this disease.[15]
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