5 Month Old Suddenly Starts Growling - Aggression?

Our 5 month old staffy/JRT cross has suddenly growled (three times now) when sitting on our knees. She has chosen to sit there, but today, in my case, I gently lifted her to move her onto the seat behind me so I could stand up, and she did a very aggressive sounding, loud growl.

I had her checked by the vet a couple of weeks ago and she could find nothing wrong physically. Pup can from a rescue at 9 weeks. She has done puppy socialisation and training classes, has a few basic commands and a good recall, and is generally an affectionate, nice little pup.

I know at 5 months she is maybe hitting adolescence. She is also very obviously teething right now which may make her grumpy. I can't account for it in any other way. She has also growled at my 14 year old and my 20 year old - again, when she chose to sit on their knees and they moved...

I am trying not to panic. We love her very much and want to do our best for her. I can get advice from the behaviourist at the rescue (who was her puppy class trainer so he does know her). The rescue felt the litter was just a case of irresponsible backstreet breeder rather than a cruelty case, as such. So they felt she hadn't been mistreated in the 8 weeks she was with her mum. She was only in rescue one week and they started socialising etc.

It shocked me today as she had been very friendly and affectionate all day. She also, simultaneously seems to have lost her toilet training (I must have cleaned up half a dozen accidents today - she had seemed to be getting it...)

She was quite a mouthy pup but was just growing out of it this past month.

We are very experienced dog owners. I am in my 50s and have had dogs all my life, so have never not known how to pick up, move or handle a dog. My kids have also had dogs all their lives.

We have used only positive training methods and positive reinforcement and ignore bad behaviour but today when she growled I put her immediately down on the floor (my heart was pounding but I tried to give only confident body language). And said "No!" loudly.

How worrying is this? Is this normal teenage pushing-the-boundaries? Is she capable of aggression at only 5 months? (20 weeks exactly). And how should I handle it?

I never punish a dog for growling. It is their way of telling you something is wrong. If they learn not to growl they have no way of telling you they are unhappy/in pain/scared or however they are feeling and only have one option left - a bite.
I would suggest teaching her to get down on command. Simply encourage her onto the sofa or bed and praise then throw a treat on the floor and say 'off' or what ever command (but not down if you use if for lay down...). Repeat a few times for short sessions and have a few sessions each day. Once she is reliable for you get your kids involved using the exact same technique. Then try it on someones lap. If you need to move her, ask someone to get you a treat first, then work on asking her then getting a treat (telling her she's a good girl, let's get a treat and taking her with you, talking all the time to drag the reward out and link to the getting down), then randomly a treat, a fuss or a play with a toy. I always make sure I tell my dog he's a clever boy when he does as I've asked so he knows he's done the right thing. My OH often forgets and my dog is a monkey for ignoring him.
Also work on handling, I'm sure you will have covered some of it in class, but make sure she is fine being touched all over. Again use treats after ever touch, gentle praise and a tickle where she likes it. Keep working and once there is absolutely no response (pulling away, swiveling head around ect) then work on putting your hands on her like you're about to lift, but don't. Reward and repeat until she is fine again or for at least a day or two if there is no reaction at all. Then apply more pressure and as before repeat until no reaction or a day or two. Then lift slightly off the floor and put her back down. Reward, repeat... Tiny step by step until she knows being picked up is okay and is followed by a treat, an ear scratch and being told she's a clever girl. Then get the others in the family to do it, starting at step one (touching all over) and following the steps, not rushing, a few days between each step and only if she is ready, calm and not reacting. If she reacts badly (whines, runs off, pulls away sharply or growls) then go back a step or two. It will take time.
In the meantime try not to let her on your lap, if she comes to sit on you try encourage her to sit next to you or stand up to make it clear your not a chair.

Chances are she is teething and dealing with hormones and possibly even coming into heat (I've seen puppies at 4 months) so it might be a phase. But we don't want you, your kids or her developing any problems with being close, lifting and becoming fearful of each other (her included in this).

Oh wow, SarahJade, what brilliant advice. I will follow that to the letter and let you know how I get on.

If anyone else has some advice, please chime in - I just want some perspective. I suppose she is in some ways a toddler, in some ways a teenager.

I agree with you re. the growling being a useful thing and not something to suppress. (I once fostered a dog that bit suddenly with no growl, no warning of any kind, and the rescue had her PTS the next day so know from personal experience that a dog that doesn't give you any warning is not a desirable outcome).

I feel a lot of pressure to get things right with our lovely pup, as well, as she came from rescue. I don't want to start feeling scared to handle her.

Hi Pen It sounds as though you have been doing a really good job with you puppy.
If may just add a little to SJ’s good avice.
I would try not to encourage your puppy onto your laps or the furniture (it is ‘your bed’ not hers) in the first place but follow SJ’s advive if she does get up.

Instead play or sit with her on a cushion on the floor and make sure her bed is a special place to which she would want to go so I would make it cosy with a nice thick blanket and hide treats in there.
Give her lots of praise for going into it and never tell he off in the bed so she associates it with only good things

In time when she has learnt a little more coming up on your laps may be allowed again.

Thanks, Meg. Yes, she is being still allowed on the furniture but not on laps. Every time she has tried to climb on my knee, I have gently slid her off sideways... She seems a bit put out but it's for her own good! Thinking about it, I did this loads of times yesterday (she is starting to get too big to fit on my knee easily) and she growled after I did it maybe the 10th time! I could tell from the look on her face earlier she wasn't enjoying being ejected from my knee and I was more persistent about it, so maybe I inadvertently started a battle of wills...

Hi Pen I would do as suggested in post 4 and not allow her up if possible so that you are not reinforcing the unwanted behaviour. Once this is learnt she can come up occasionally at your request.