It’s early morning, and Angus is at his sweetest. He’s been out in the yard and back inside and, briefly, on my lap and then lying on top of my feet, and right this moment he is dozing in a patch of sunlight.

You would not believe, to look at him now, that for a while he was turning into Cujo on the walks.

Well, not Cujo exactly — Cujo is vicious, and Angus is not vicious. But all of a sudden, he had gotten mouthy.

This started when he was about four months old. One day he was trotting along, happy with the world, and the next day he was scanning the horizon, looking for people and dogs. When he saw them, no matter how far off, he’d let loose with a volley of barks. This was a new, unwelcome development.

We adopted Angus at the end of December. January and February were cold, dark months. Often when we walked it was just Angus and me in a big white frozen ice cube of a world. When we saw another human I’d bring Angus up and ask if they could meet, and Angus was always tail-waggingly thrilled. But on icy trails, in 2-degree weather, people were few and far between.

The barking started in March, as the weather warmed. Suddenly, there were people everywhere.

I figured he barked because he was scared. So I’d make him sit, offer him a treat, and talk sweetly to him. I’d scratch his ears in a reassuring manner.

This did not work. He’d bark, take the treat, bark again.

Angus is pretty well socialized. He lives with a dog, our Lab Rosie. He spent six weeks in puppy kindergarten, happily coexisting with other puppies. He and the Brittanies next door played together all winter, and the ivory Lab across the street comes over nearly every day. He’s been around a lot of dogs, and a lot of people.

He’s going to be a big dog (how big? don’t ask), and even though his barking seemed more excitement than aggression, I knew I needed to stop it. A big barking dog is scary, whether or not it is friendly.

So the next morning when we set out on our walk, I tried a different approach. Right away, we saw a person at the bus stop across the street. Angus opened his mouth to bark, and I gave his leash a sharp little jerk. I said, “UH-UH. Watch me.” And he looked at me and didn’t bark. I gave him treats. And then we walked on. Quietly.

We went a little farther and saw a man walking toward us, and Angus stiffened and his ears went up and just as he was about to bark I gave the leash a little jerk and I said, “UH-UH. Watch me,” and he didn’t bark.

We rounded the corner and saw another woman and I gave his leash a sharp jerk and said, “UH-UH.”

And he didn’t bark.

We’ve been doing this on every walk every day for more than two months. It doesn’t work every single time, and if he gets wound up there’s nothing to do except drag him away. (So it’s best not to let him get wound up.) But mostly, it works.

This morning, he saw Stella, the black Lab he had barked at last week. Today he didn’t bark — he looked at Stella, and then he looked at me. Before I told him to.

I praised him like crazy. I made him sit, and I stuffed him full of soft liver-flavored treats, his favorite, and he got all bouncy and happy. And then, as the sun came up, we headed for home. Me and my very good boy, the very quiet Angus.

Laurie Hertzel is the senior editor for books at the Star Tribune. She is not a dog expert, just a dog lover. She is chronicling the first months of her puppy’s life. E-mail her at lhertzel@startribune.com

Coming June 2: Who’s your daddy? DNA tests tell all. Read all of the Puppy Chronicles at startribune.com/puppy