The CFZ has, as you may know, been running a project looking into the Texas Blue Dog for a while now. However, although Jon and I have our own thoughts on the phenomenon, we would both like to know what you, dear fanatic, think on the subject.
Also, in a similar vein, we would love people to look into the following subjects to help us with our research:
- Have there been any massive wipe-outs of canine populations in Texas in the last 2000 years?
- How common is blue skin amongst canids?
- Do any species of wild canid throw up hairless sports?
- Have there been any reports matching the Texas Blue Dogs from anywhere else, either worldwide or USA based?
- Are there any ancient domestic dog breeds from Mexico and Texas that could match the Blue Dog descriptions?
- Do any canids actually drink blood?
- How many different Blue Dogs have been found dead in Texas?
Coyotes, wolves, and dogs will interbreed and produce fertile offspring. Wolves and dogs are the same species. I tend to follow the classical taxonomic definition of a red wolf and consider it conspecific with the other wolves-- just heavily polluted with coyote MtDNA through the millennia.
ReplyDeleteWe do know that black wolves of any kind and black coyotes are the result of cross breeding with domestic dogs.
http://retrieverman.wordpress.com/2009/02/06/evidence-now-suggests-that-black-wolves-in-italy-and-north-america-got-that-coloration-from-interbreeding-with-dogs/
The hind dewclaws in Italian wolves are the result of hybridization with domestic dogs (it is used as a diagonistic for hybridization):
http://news.bbc.co.uk/2/low/science/nature/3602741.stm
I just recently wrote about some "red wolves" that were found in Florida (which the Fortean Zoology Blog linked to in the past week.) However, these animals were coyotes with tons of white on them:
http://retrieverman.wordpress.com/2009/09/02/i-dont-think-these-are-red-wolves/
The white comes from crossbreeding with domestic dogs.
It turns out that a substantial minority of coyotes in the Eastern and Southern parts of their range have dog MtDNA-- meaning they had a female dog ancestor somewhere.
http://www.ncbi.nlm.nih.gov/pubmed/12535104
Generally, female dogs can have puppies with male coyotes. That's because female coyotes are fertile only over a narrow window, and because most female coyotes won't allow themselves to be bred by dogs. However, female coyotes have interbred with male wolves in the wild, especially in the red and Eastern North American wolf populations. As wolves disappeared and coyotes moved in, they started interbreeding.
I don't know what is causing the blue dog phenomenon (I'm not talking politics here).
It could be mange.
It could be that some Texas coyotes are evolving a hairless trait to avoid infestation from ectoparasites.
We also know that all hairless dogs descend from Latin American dogs that are thought to have originally evolved that trait to avoid ectoparasites.
We also have lots of street dogs in Latin American, including Mexico, that have hairlessness. http://www.dogbreedinfo.com/hairlesskhala.htm
This gene could have been introduced into Mexican coyote population, which then dispersed into Texas.
However, the gene that causes this is a dominant gene that also causes weak dentition. I'm not seeing weak dentition in that frozen blue dog.
I can talk about this at length if anyone is interested-- just e-mail me at retrieverman1@yahoo.com
I am not an expert biologist or geneticist, but I have been carefully reading the peer reviewed articles on dog, coyote, and wolf evolution and ancestry for some time.
Gray foxes (Urocyon) sometimes are single coated (called Samson foxes because they lose their hair):
ReplyDelete1. http://wildlifemysteries.files.wordpress.com/2009/05/samson-fox.jpg?w=316&h=245
2. http://wildlifemysteries.files.wordpress.com/2009/05/samson-fox-ii.jpg?w=600&h=414
3. http://wildlifemysteries.files.wordpress.com/2009/05/samson-fox-iii.jpg?w=350&h=278
The last one is a gray fox. They sometimes come in this red coloration when they are in a Samson form.
Blue skin is represented by the genotype B/B or B/b. My golden retrievers have all had this skin color. If you were to clip my dog (and my sister nearly did) down to the skin, you would see this skin color. Goldens have another genotype e/e that prevents the black skin color from appearing on their coat. e/e dogs vary in color from white (poodles, white GSD/Alsatians) to deep mahogany colored (red setters).
ReplyDelete