Hello, I’ve got a 6 months Pointer mix puppy. He’s with us for 2 months. He’s been a decent lad, except some trash eating issues, which we have solved. Now, I’ve came to see my family, and we stay at their place. He knows them for 2 days. He was pretty calm since they’ve met. Yet, yesterday, when I was working in the living room, as he was sleeping, my sister came up from her room to grab a cup of water, and he suddenly started barking and growling at her. What may be the reason for that behaviour? I’ve heard him barking for the 3rd time maybe.