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.
One thing worth considering is that some types of dog are more likely to be aggressive than others.
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 other retain the wilder characteristics.
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.
That said, here are the 20 breeds of dog most and least likely to show signs of aggression.
Make sure you don't miss a moment of breaking news from across Scotland by signing up to our free newsletter here.
5. Alaskan Malamute
What is true of the Husky tends to also be true of the their close cousin the Alaskan Malamute - and that's the case with possible aggression. They are even bigger than Huskies though, meaning it's even more important for them to be trained properly. | Canva/Getty Images
6. Rottweiler
While the Rottweiler's reputation for uncontrolled aggression is slightly unfair, it is a breed of dog that has the potential to be aggressive. The dog's upbringing is key - a well-trained Rottweiler with an experienced owner can be a placid and loving dog, but this isn't a breed for novices. | Canva/Getty Images
7. Dobermann
Dobermanns are usually fiercely loyal to their owners but that can also result in signs of aggression to strangers. Early socialisation is a must with this muscular breed - who make great guard dogs. | Canva/Getty Images
8. Chihuahua
A classic example of small dog syndrome, the Chihuahua has a tiny body but a big attitude. Regular unpredictable bouts of aggression are not uncommon, meaning they are not a good choice for families with small children. | Canva/Getty Images