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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5. Old English Sheepdog
Unless your idea of guarding a home is licking intruders into submission, then the Old English Sheepdog just isn't up to the task. | Getty Images for Westminster Ken
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6. Saint Bernard
A classic gentle giant, the enormous Saint Bernard may look intimidating but they have less aggression than a tiny Chihuahua (who make surprisingly good guard dogs). Maybe an unwanted visitor might slip up on this dog's drool, but that's about the only resistance they'll typically put up. | AFP via Getty Images
7. Golden Retriever
What's true of the Labrador Retriever also usually applies to their close cousin the Golden Retriever - including their lack of guard dog attributes. If they think there's a snack in it for them, they'll probably happily share the location of your valuables. | AFP via Getty Images
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8. English Bulldog
The English Bulldog's forebears would have been superb guard dogs, but this is a breed that has long since had their aggression bred out of them. Now they are unlikely to even stir from napping on the couch should something untoward be happening. | AFP via Getty Images