A study was conducted in the United Kingdom, examining 585,000 dogs to determine the lifespan of different breeds. Large breeds and those with flattened faces were found to have shorter average lifespans than smaller breeds and those with elongated snouts. Female dogs were also found to live slightly longer than male dogs. The study concluded that more research is needed to understand why some breeds have shorter lifespans than others, and that some breeds are genetically predisposed to health problems.