Why is my new puppy suddenly aggressive towards my partner?

I just got a 3-month-old Chihuahua named Ripley. At first, she was super affectionate with everyone in the house—me, my partner, and our kids. But today, out of nowhere, she growled, lunged, and even bit my partner when he tried to pat her. She’s fine with me and the kids but seems really wary of him now. I’m worried because we have visitors a lot, and last night, she growled and avoided them too. Could this be because she wasn’t socialized well by the breeder? Or maybe something else is going on? How can I help her get comfortable with everyone? I’ve already booked her for puppy school next weekend, but I’m nervous they might not let her in because of this behavior. Any advice?

Sounds like she might be resource guarding you. Does she act protective when your partner or visitors get close to you?

DeepikaPadukone said:
Sounds like she might be resource guarding you. Does she act protective when your partner or visitors get close to you?

Yeah, now that you mention it, she does seem extra clingy to me and growls when anyone comes near. How do I stop that?

@Braint
You can try positive reinforcement training. Give her treats when she interacts calmly with your partner or visitors.

@Braint
Seconding this. Keep it consistent and don’t rush her. It takes time for them to adjust.

Could her behavior be linked to something that happened with your partner? Even accidentally? Like he stepped on her paw?

Shaniera said:
Could her behavior be linked to something that happened with your partner? Even accidentally? Like he stepped on her paw?

I asked him, and he’s sure nothing like that happened. It’s weird because she acts like this with visitors too.

Shaniera said:
Could her behavior be linked to something that happened with your partner? Even accidentally? Like he stepped on her paw?

Maybe she’s just overwhelmed. It’s a big adjustment for a little pup to get used to a new home and people.

You mentioned she just got her vaccination—could that be affecting her mood or making her uncomfortable?

BrianCopland said:
You mentioned she just got her vaccination—could that be affecting her mood or making her uncomfortable?

The breeder mentioned that too. Do you think that could really make her this grumpy?

@Braint
It’s possible! Vaccines can sometimes make dogs feel off for a few days. Keep an eye on her and see if it improves.

Don’t worry too much about puppy school. They’ll probably be okay with her if you explain the situation. Just work on her socialization in the meantime.

Bitchshaper said:
Don’t worry too much about puppy school. They’ll probably be okay with her if you explain the situation. Just work on her socialization in the meantime.

That’s a relief to hear. I’ll keep trying to get her more comfortable with everyone before next weekend.

Try having your partner feed her and give her treats so she associates him with good things.

EdwardGenesis said:
Try having your partner feed her and give her treats so she associates him with good things.

Good idea! I’ll ask him to start doing that and see if it helps.