Large dogs are a popular pet choice for many people. Two of the most well-known large dog breeds are Mastiffs and Great Danes. Mastiffs are a large, powerful breed of dog with a short coat and a muscular body. They typically weigh between 120 and 230 pounds and can stand up to 30 inches tall. Great Danes are also a large breed of dog, but they are more slender than Mastiffs. They usually weigh between 100 and 200 pounds and can stand up to 32 inches tall. Both breeds are known for their loyalty and intelligence.