Dogs come in all shapes and sizes - the UK Kennel Club recognises 221 different pedigree dogs, from Affenpinscher to Yorkshire Terrier (there are sadly no dog breeds starting with the letter ‘z’!).
Then there are all manner of crossbreeds, from so-called ‘designer dogs’ to lovable mongrels.
Each has its own list of positive and negative attributes, and it’s important to take plenty of time to think about what breed will fit into your lifestyle the best - for instance a smaller dog if you live in a flat, or a hypoallergenic dog if the mere mention of dog hair makes you think about sneezing.
There is even scientific research to guide you, in particular psychologist Stanley Coren’s groundbreaking book The Intelligence of Dogs.
And one thing you might like to consider is that some dogs are naturally better guard dogs than others.
Labrador Retrievers may be affectionate and popular, but they’re likely to welcome a burglar like a long lost friend - particularly if they come armed with a few tasty sausages.
On the other hand, other breeds are naturally suspicious of strangers, ever-vigilant and have the potential to be ferocious if challenged or confronted. It also helps if they look a bit scary.
Here are the 24 best and worst breeds of guard dog.
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17. Beauceron
A fairly rare breed in the UK, the Beauceron was originally used to herd animals in its native Central France. Also known as the Bas Rouge, on account of its red 'stockings', its remarkably sensitive sense of hearing means it will be aware of an approaching threat while other dogs are still asleep. | AFP via Getty Images
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18. Akita
In Japan, where they originate, the Akita is the last word in guard dogs. This is another breed whose extreme vigilance and distrust of strangers mean they can be trusted to keep your safe - and they have the muscle (and teeth) to back it up. They are also playful and loving companions - as long as you keep on their right side! | AFP via Getty Images
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19. Dobermann
Known as the Doberman Pinscher in the USA, the American Kennel Club describes it as "incomparably fearless and vigilant" - pretty much the definition of a perfect gaurd dog. | Getty Images for Westminster Ken
20. Rottweiler
A breed that have, at time, got a bad reputation for being aggressive, a well-bred and trained Rottie will only demonstrate aggression when it, its home or its family are at risk. When not on duty they are calm, confident, loving and playful animals that make great family pets. | Getty Images