For some reason, people are far less likely to adopt blacks than yellows, and so blacks are more likely to be euthanized. Dogs and cats – why, what’d you think? Some folks think it’s because their faces are somehow harder to read when covered in black fur, but that seems rather lame; at least it’s never been a problem in my experience.
More likely, it’s just association: black cats were witches’ familiars, whereas black dogs were villianized time and again in British novels:
From Arthur Conan Doyle’s “The Hound of Baskervilles” to Wiltshire’s “Black Dog Hill,” the dark-furred canines are regarded as “portents of death.” These evil dogs are often portrayed as larger than the average dog, “black as the night,” and unequivocally snarlish.
Whatever the basis, having a black coat fast-tracks the animals to an appointment with a needle. Maybe the only answer is to require folks who adopt a yellow or a gray also to adopt a black. Or just get them to wise up and adopt on the basis of personality. Trail tip: if a black cat crosses your path, it does not portend bad luck.