Related: The 7 Friendliest Dog Breeds—For People Who Want a Dog That Loves Everyone (Even Strangers) Golden Retriever (n.d.).

These massive canines range from intimidating guard dogs to benevolent rescuers. Check out the backstory behind the brawn. The 15 Biggest Dog Breeds in the World ...

Bullmastiffs are domestic guard dogs from the 19th century. ... Male bullmastiffs weigh around 110 to 130 pounds, and females are 100 to 120 pounds — an excellent size for big, strong guard dogs.

Svalinn, like many guard dog breeders, does not place dogs with owners often. The company "sells no more than 20 dogs a year and only about 350 exist around the world," said New York magazine.