A giant dog breed is a breed of dog of gigantic proportions, sometimes described as a breed whose weight exceeds 45 kilograms (100 lb).[1] Breeds sometimes described as giant breeds include the English Mastiff, Great Dane, Newfoundland, St. Bernard and Irish Wolfhound.[2] These breeds have seen a marked increase in their size since the 19th century as a result of selective breeding.[2]
Dog breeds described as giants tend to have more health problems than smaller dogs and have the shortest life expectancy of all dog breeds.[3]