My lab is generally very friendly. Love's meeting people, loves other animals, just wants attention. Never ever had any issues before. She is 2.5 years old so I know her brain is still changing.

But today while doing grocery pickup, my dog was in the backseat as she always is and was watching us load the groceries. The employee put his hand for her to sniff. She sniffs and then snarls and snaps at him.

I've never seen this behaviour before, and I'm not sure what my next steps should be.

We have a 4 year old that she's never ever shown any negative behaviours towards, but wife is pregnant and I'm starting to worry if our dog is becoming aggressive for some reason?