Aggressive dog

[Iloverupertp]

My dog has always been friendly and easy going but has started to get really aggressive to one particular dog that lives near me
He has never actually attacked it but yesterday my mum took him out and he actually attacked the dog and the owner fell over trying to separate them
This other dog is lovely and gentle so I have no idea why my dog dislikes him so much
Any ideas why a dog becomes aggressive out of the blue?she said she will
Report him to the police if it happens again.
He’s always been fine but has become a little bit more narky with other dogs too recently but not to that extent
Any advice would be much appreciated

Did your mum have your dog on the lead?
I would get the dog checked over by the vet to make sure it isn't a physical problem, and then I would be walking it on a lead in a muzzle if there is any danger of other dogs being around. What breed is he? Is he strong and can your mother control him?
We had an old dog that liked all dogs except one, who was his size (small) and old as well. The dogs used to wind each other up - the feeling was mutual. I bumped into the owner and dog one day as I went round a corner (we usually managed to avoid each other) and they had a terrific (if rather slow and arthritic) set to before we could separate them, and they were both on leads. There were no repercussions because it was six of one and half a dozen of the other.
I feel sorry for your lady as she fell over. It must have been very frightening for her.

I'd go for a vet check - a dog that suddenly becomes aggressive is often in pain. As with humans, pain can make a dog rather grumpy.

In the meantime, avoid the other dog like the plague (we've had a couple of dogs that DDog just didn't like and avoidance was always the most practical option)

What was the scenario? As in, what are the answers to the following:

Were the dogs on a lead? Is your dog fixed? Is the other dog fixed? What are the genders of the dogs involved? What ages? Have they ever had the chance to meet on neutral ground?

All those things can have an impact on temperament and behaviour.

On top of everything already mentioned, often this kind of thing can be a bit of a downward spiral.

e.g.

1. dog is a little bit nervous of another dog, maybe simply because it struggles to read that particular dog's body language.
2. Dog growls or barks to keep other dog away
3. Dog gets told off for barking, which is a bad experience
4. This confirms to the dog that the other dog is trouble because he links the appearance of the other dog to the telling off (not it's own barking behaviour)
5. Dog tries extra hard to keep the other dog away next time, upping the barking, lunging
6. Dog gets more of a telling off

and so on

Eventually you get to...

Dog has escalated the original bark to maximum and gets into a fight with the other dog because no amount of barking seems to be working at keeping it away. The fight is a masively stresful and unpleasant experince so the dog develops a hard core fear of that other dog.

If this is just one dog, keep them well apart, ideally never let them see each other. If you have to pass in the street take whatever long route allows you to keep maximum distance between you. If your dog reacts in any way, you are too close.

Thanks for the reply’s
Both dogs were on leads.my dog is small but my mum wasn’t holding the lead tight enough.
They’re a similar size but I think the other dog is about 1
They’ve been on the field together in the past and no problem.It seems to be the combination of the woman and the dog as I’ve seen the son walking the dog and my dog didn’t really react
I did tell my dog off.should I not do that ?
I will try and avoid as much as I can but they walk past my house everyday.I think it must be a protection thing as he really barks when they go past(my dog sticks his nose under the gate)
I’ve told my kids to keep him on the lead at all times
Thanks for the advice so far

I'd start with your vet and make sure that there isn't anything causing your dog to be in pain. And then find a good local dog trainer to work one to one with you so that you are able to distract and control your dog when this other one is around. I've got a nervy dog who came on leaps and bounds with professional guidance.

Your dog could be acting with aggression out of fear, not necessarily malice.

How old is he?
If he's only just reached adulthood that could be a factor imo, some young dog social dogs suddenly aren't terribly social anymore when they reach maturity.

And is he or the offensive dog neutered?
Some males really dislike unneutered males.

My dogs 4 and is neutered
I’m not sure about the the other dog.hes about 1 I think

Probably not an age thing then.
Maybe the other dog is unneutered and he takes offence to that if he's generally okay with other dogs