Dogxim, Wikipedia
Dogxim, is the name given to the female pampas fox (Lycalopex gymnocercus), claimed to be a hybrid between a domestic dog and a wild pampas fox, discovered in Brazil during 2021.
The unusual coat colour, pattern and behaviour of the fox is what led to the assumption the animal might be a hybrid and a genetic test was carried out. The test indicated a mixture of fox and dog genetics and in 2023 it was announced that the animal was a distinct hybrid genetically and that the animal "represents the first documented case of hybridisation between these two species". However, these results alone are not enough to prove the theory, as they can not be confirmed.
Feugian Dog, Wikipedia
There are several things that 'irk' me regarding this case:
The appearance of novel colour mutations is usually a sign of adaptation in a species, which can occur for many reasons including; as a result of domestication, as a result of adaptation to disease risks, a genetic response to dietry or environmental changes and as a result of hybridisation. Genetic information can also be passed from species to species without hybridisation, as a result of 'Jumping Genes' (retrotransposons - eg. 25% of cow and sheep genes are 'jumping genes').
The occurance of unsual behaviour is usually a sign of injury, illness or habituation and domestication. The foxes of South America were once domesticated in the form of the 'Feugian or Yaghan Dog'. These domesticated animals occured in many coat colour variations and were deemed extinct by 1919. It is important to add here that the foxes of South America are all capable of hybridisation and should any of the domesticated South American foxes had of survived, their traits could potentially have 'lived on' in the background of the local fox population as hybrids. It is not unknown for extinct species to be rediscovered and we have little data on these domesticated foxes. There are also Pampas foxes bred in captivity for zoos and animal attractions, which can also display novel coat colours and I doubt very much their genetic profiles and novel traits are documented within genetic databases.
We have no way to confirm that the sample was not contaminated at all. The animal had been involved in an RTA (did it lack road awareness, as is the case for many captive bred animals?) and was being cared for by an animal veterinary hospital where the sample (a 5 mm surgical punch) was taken for analysis, before being moved to an animal shelter where it subsequently died. Without the knowledge of the researchers, the body was disposed of. An act the Brazilian government is investigating. There is no way to know if that sample had been contaminated or not (eg. with a dog hair, as the surgery was performed in a Brazilian veterinary practice and then the small sample was sent to the researchers). No further samples can be taken and no other such animals are known to exist (foxes are born in litters of up to 8 cubs, so this animal will have siblings).
Undocumented and novel mutations cannot be matched in genetic database systems that do not have that information, the system will find the nearest match. A similar mistake of assuming novel coat colour and behaviour was due to hybridisation occured in 2012 when a domesticated fox was mistaken by the scientific databases, for being a fox-raccoon dog hybrid. This animal was a known escapee (one of two out) and a captive bred 'silver fox', while it did live with raccoon dogs (could also have been a contaminated sample), it was not a raccoon dog hybrid, it was 100% North American red fox (NARF). The scientists were notified before they made their study results public.
Albino Pampas Fox, M’Bopicuá Biopark, Uruguay
In conclusion:
While the animal certainly was an anomoly, upon appearances, I would first have assumed I was witnessing a tamed or domesticated Pampas fox, with a novel and undocumented coat variation. There are more possible explainations for this novel presenting animal than just hybridisation alone and a single experiment with a small sample, that can not be confirmed, is not enough evidence for me to agree it really was a fox-dog hybrid. Any canine DNA can also be attributed to sample contamination.
If it was a dog-fox hybrid, there will be more and the result can be confirmed.
