All dogs go to heaven, but some dogs get there a little earlier than others because of a quirk linked to their luscious locks. According to new research led by the University of Sydney, the life expectancy of Labrador retrievers is connected to the color of their coat. These good boys might come in black, yellow, and brown — but one of those pigments is more unfavorable than the rest.

In a study published Sunday in Canine Genetics and Epidemiology, scientists reveal that chocolate Labradors live for a significantly shorter amount of time than their counterparts. Currently, this can only be said for chocolate Labradors that live in the United Kingdom, cautions lead author Paul McGreevy, Ph.D., who notes that Labs in other countries haven’t been studied in the same way yet. Still, his study’s results warrant a similar investigation.

McGreevy and his team studied more than 33,000 Labradors in the UK and found that, across all of them, the most common health conditions were obesity, ear infections, and joint conditions. The brown-colored dogs, however, had more health problems than the rest. They developed significantly higher incidences of ear infections and skin diseases. Among the chocolate Labs, the prevalence of ear inflammation was twice as high and the pervasiveness of a skin condition called pyo-traumatic dermatitis was four times as common.

Good but cursed boys. Wikimedia Commons

Unfortunately, the higher rates of these illnesses mean chocolate Labradors have lives that are about 10 percent shorter than non-chocolate dogs, which typically live to be about 12.1 years old. The scientists reason that the gene for chocolate fur comes with a very high price.

“Because chocolate color is recessive in dogs, the gene for this color must be present in both parents for their puppies to be chocolate,” McGreevy explains. “Breeders targeting this color may therefore be more likely to breed only Labradors carrying the chocolate coat gene. It may be that the resulting reduced gene pool includes a higher proportion of genes conducive to ear and skin conditions.”

To see whether these results hold true in different countries, a similar survey is currently being replicated in Australia. Labradors are the most popular breed of dog Down Under, but they’ve got their fans in the United States: For the past 26 years the American Kennel Club has ranked the sweet breed as the most popular dog in the country.