23. Great Dane
The Great Dane is one of the largest dog breeds out there. However, it is actually quite gentle and affectionate with its humans despite its size. Due to its size, it lives a much shorter lifespan than most other breeds. There are a wide variety of coat colors for this breed, and they have a gait that gives them all the grace and poise of a ballerina. Gentle nature aside, intruders may look at the size of a Great Dane and think twice about trying to get inside. They make friends easily and are always looking to make their owners happy.