The dogs we live and work with today have come a long way thanks to generations of evolution and breeding. Yes, it’s crazy, but whether we’re talking about that fiery little Chihuahua, that energetic Labrador Retriever or that super-fast Greyhound, all of our dogs originated from wolves a long time ago. In fact, archeologists have discovered human remains from thousands of years ago buried with the remains of a dog nearby. It turns out that man’s best friend has held that title for quite some time. Today, we use dogs for all sort of things. They entertain us, keep us company, hunt and retrieve, and even guard us. In fact, in terms of guard dogs, there are some pretty large breeds that are intimidating even to look at. Yes, in the realm of dog-human interaction, the role of guard dog has been around for a long time. Guard dogs come in all shapes and sizes but they serve the same purposes – to protect livestock, property or even the humans of their ‘pack.’ Ahead you’ll see dogs like the Boerboel and Dogue de Bordeaux, two breeds used to guard homesteads and even the castles of the elite. Looking to protect livestock as well? Then be sure to watch for the Kangal and Fila Brasileiro. Both of these dogs aren’t only big but extremely loyal and intimidating. The Greater Swiss Mountain Dog and Tibetan Mastiff both originated in mountainous and harsh environments – so you know these breeds are tough and mean business when they bark. Don’t get fooled by the Komondor. It may look like an oversized mop – but if you try to mess with the herd it’s guarding it’ll mop the floor with you. The same can be said of the Great Pyrenees. It may look like an oversized Golden Retriever, but this large dog will defend animals and people with great courage and loyalty. With a well-established history of protecting estates from wild dogs, the Perro de Presa Canario is one large breed we don’t think you should mess with. The same goes for the Caucasian Shepherd. This massive dog has evolved to meet the rugged environment of Southern Russia and the Caucasus, so you know it can hold its own when it comes to a fight. All in all, we’re pretty sure you don’t want to mess with any of these massive breeds.