ASK THE VET.
Byline: With Rory Thomson
Q: Dylan, my five-year-old male shih tzu is a rescue dog and is very aggressive towards other dogs when out for a walk. He pulls on the lead to get to the other dogs - he is OK with adults and children, he only goes after big dogs.
Why is this? Dylan Mays, Tyneside A: This is a behavioural issue that really needs addressing with an accredited pet behaviourist. Although a shih tzu is a small breed and therefore less likely to do much harm to a larger dog and is not showing any aggression towards adults or children, he can still cause some damage to another dog. His behaviour towards another, much larger, dog could also elicit a retaliation from the bigger dog, which could be much more dangerous and so this behaviour needs to be addressed and managed effectively.
There are various theories as to why small dogs seem to go after bigger dogs and it is difficult to be certain as to what is going through an animal's mind. The cause is likely to vary between individual dogs. One theory is that the smaller dogs, being carried in their owners arms, gives them a feeling of being bigger than they are and a false level of confidence. Another theory stems from the genetic breeding of some terriers to have a low arousal level and feisty attitude to seek and attack animals larger than them through illegal, blood sports (that are thankfully now illegal).
It may be that the initial behaviour started out of fear of a larger dog approaching him and a warning bark caused the larger dog to submit and retreat. This response, if repeated a few times, may have reinforced the bad behaviour. There may also be a hormonal element if he has not been castrated.
IF you have got any questions about your pets, you can email them to Rory Thomson: firstname.lastname@example.org