Shelter workers call it the "Black Dog Syndrome": Black dogs and cats are often the last to be adopted and the first to be euthanized.
There are no statistics, but there is plenty of anecdotal evidence and many possible explanations, ranging from superstitions like the notion that black cats are bad luck, to a simple logistical problem: Black animals are hard to photograph well, and are therefore hard to advertise.
"Overwhelmingly, we hear from the shelter and rescue groups that black dogs, especially the big black dogs, and black cats take longer to get adopted," said Kim Saunders, vice president of shelter outreach for Petfinder.com, the country's largest online pet adoption database.
Some have called Black Dog Syndrome a hoax, but Inge Fricke, director of sheltering and pet care issues for the Humane Society of the United States in Washington, D.C., insists "it is not a hoax. There is definitely anecdotal evidence. There haven't been any definitive studies to absolutely prove that the phenomenon exists but it is something commonly accepted by shelter workers as truth."
Some in the adoption business think there may simply be more black dogs and cats than animals of other colors. Others think the animals may be wrongly perceived as menacing.
Mike Arms, president of the Helen Woodward Animal Center in Rancho Santa Fe, Calif., blames part of it on typecasting. "If you think of any movie with a mean, devil dog, it's always a black dog, and if you see a witch in a movie, they always have a black cat."
Shelters will change lighting, use light-colored blankets, and dress up animals to try to get better photos for websites, ads and fliers, Fricke said. "The easiest way to make a black dog look friendly is to put it in a bright colored bandanna," Arms said. "Who pictures a devil dog in a yellow bandanna?"
"If you are thinking about adopting a dog, please don't overlook black dogs. They are every bit as wonderful as lighter colored dogs, and make just as loving and faithful companions," said Alyce Russell, volunteer executive director of California's Glendale Humane Society.
For years, many shelters stopped offering black cats for adoption around Halloween because some cats were being abused. But that thinking is changing.
Applicants are screened better these days, the cats have microchips and too many cats might be missing out on good forever homes, said Beth Chee at the Woodward center.
"We really encourage shelters and rescues not to stop promoting adoption of those pets at this time of year," Saunders said.