A new study suggests that the life expectancy of chocolate Labradors is significantly lower than their black and golden counterparts.

Who’s a good boy? All of them. Image credits: sgilsdorf / Flickr.

Labrador Retrievers have firmly established themselves as one of the most popular dog breeds in the world. Friendly, active, and high-spirited, labs are famously lovable. But not all labs are alike, a new study has revealed. Three types of labs are generally recognized: black, chocolate, and yellow. A new study has revealed significant health differences between these types, and it’s not exactly clear what’s causing them.

The median lifespan of Labrador retrievers overall was 12 years but was much shorter in chocolate dogs,” the study writes. “The most common causes of death were musculoskeletal disorders and cancer. More generally, the most common disorders affecting Labrador retrievers were overweight/obesity, ear and joint conditions. Skin and ear disease were significantly more common in chocolate dogs than in black or yellow dogs.”

Labrador retrievers have shown predispositions to a wide range of diseases and health conditions. They have a tendency to eat more than they need, which can lead to obesity (and the range of issues associated with it). The study, which was based on 33,000 United Kingdom-based Labrador retrievers of all colors, found that 8.8 percent of labs are overweight or obese, one of the highest figures reported in all breeds. Being overweight/obesity was not statistically significantly associated with neutering in females, but was associated with neutering in males, which were also significantly heavier overall.

As a breed often associated with swimming, they also have an increased risk of ear inflammation and are predisposed to gastrointestinal disorders and musculoskeletal disorders, among others. But there were major differences associated with hair color. For instance, the prevalence of a common ear inflammation (otitis externa) was twice as high in chocolate Labradors. Chocolate labs were also four times more likely to have suffered from pyo-traumatic dermatitis (also called hot spot).

Chocolate labs seem more predisposed to health issues.

Lead author Professor Paul McGreevy says that discovering a connection between hair color and disease predisposition and lifespan came as a surprise. He says that this connection has not been signaled in other breeds and could be extremely important for breeders and owners.

“The relationships between coat colour and disease may reflect an inadvertent consequence of breeding certain pigmentations,” he said. “Because chocolate colour is recessive in dogs, the gene for this colour must be present in both parents for their puppies to be chocolate. Breeders targeting this colour 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.”

It’s not clear what the cause for this correlation is, and whether it carries out on other populations. McGreevy and colleagues call for further research.

The findings were published in Canine Genetics and Epidemiology.