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.
Before they were domesticated, dogs had to fight for everything from food to territory – so signs of aggression were essential to their survival.
Many of these has been bred out to create the perfect family dogs we know today, but some breeds are more likely to retain an aggressive side than others.
There can be good reason for this – for example for those used as service or guard dogs – but prospective owners should be aware that this is the case before choosing to welcome a certain dog into their homes.
It should also be said that individual dogs may display attributes that are unusual for their breed, and all dogs have the potential to be aggressive in certain situations.
Here are the 12 breeds most likely to show signs of aggression – including growling and snapping.
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5. German Shepherd
Aggression isn't always a bad thing in a dog - the German Shepherd's temperament means that it excels as a forces dog, police dog and guard dog. While it's not a dog to get on the wrong side of, if the aggression is channelled in the right way it can be a great pet that is sure to protect its beloved family. | AFP via Getty Images
6. Akita
The Akita is essentially Japan's equivalent of the German Shepherd - commonly used as police and guard dogs. Again, it's important to make sure its natural aggression is put to good use. | AFP via Getty Images
7. German Spitz
The may look like fluffy balls of fun, but the German Spitz has a reputation of being highly suspicious of strangers - both human and canine. They can be highly reactive, lashing out when nervous. | AFP via Getty Images
8. Jack Russell
Energetic, bold and tenacious - the Jack Russell Terrier can become hyperactive without firm training and exhibit aggressive behaviour such as nipping, snapping and chasing. | Getty Images