Turns out, it has something to do with their genes! No, really:
Tosso Leeb of the University of Bern in Switzerland and colleagues report that dogs that are hairless or nearly so have a mutation in a gene they call FOXI3.
The researchers compared the genomes of hairless and coated dogs from three breeds — the Chinese crested, and the Mexican and Peruvian hairless. It had been known that hairlessness (accompanied by tooth abnormalities) in these breeds is caused by a single dominant gene, but the precise gene was unknown.
Oh thank God. Finally, we can bring some peace and dignity to bald dogs everywhere. Just a few cycles of painful gene therapy and these proud puppies will be back on their paws, romping through a dewy meadow with a thick, lustrous coat of hair.
I know this isn’t good news for my line of dog toupees (aka Dr. Barky’s Hair Restoration System), but I was always in it for the dogs. Always.
That Dog Is Bald, and Now We Know Why [NY Times]