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.
A dog’s IQ has a bearing on how easy it is to train - although a brainy pup still has to want to do what it’s told to be considered highly trainable, so it’s not all about intelligence.
Some breeds tend to have a range of attributes that mean it’s pretty easy to get them heading outside for the toilet, sitting, staying and walking to heel. Others, however, tend to be a little trickier.
It should be noted that every dog is an individual so there is no guarantee that any particular animal will have the traits common to its breed.
Having said that, here are the 12 breeds that tend to be the hardest to train.
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9. Basenji
Famously the only breed of dog that doesn't bark (it makes an odd yodelling noise instead), the American Kennel Club advises that crate training is an obsolute must when it comes to this unusual breed. Characterised as "having a stubborn streak a mile wide" they use their notable intelligence to get what they want - even if it isn't what their owner wants. | AFP via Getty Images
10. Irish Setter
The Irish Setter has such energy levels that it finds it difficult to concentrate on training for more than a short period of time. They also take longer than most breeds to mature, so will also retain their puppish naughtiness for longer. | AFP via Getty Images
11. Bulldog
The Bulldog is a breed that can be exactly as stubborn as it looks. Their two favourite things to do are to eat and to sleep - getting them to do anything else can be a real challenge. | Getty Images
12. Chow Chow
Chow Chows are a very mild-tempered dog, but are another dog described by the American Kennel Club as "aloof". So they'll always be very pleasant about ignoring every word you say. | Getty Images