Pit, for the most part, has been a very silent dog up until recently. He'd growl and squeal when playing with me and other dogs but never ever made a peep at the sound of a doorbell, people knocking or people walking by our fence. I'm currently boarding two very vocal labs and it seems as though since they've come here, Pit has picked up some very annoying habits I had hoped I wouldn't have to deal with since he never displayed any of them before. If someone walks above my room, the labs will growl and bark, if someone comes to the door, they bark, if someone talks outside the room we're in, they bark. Pit now thinks it's a great idea to do the same and I can't stop them. To add to the joy, one of the labs marks excessively and Pit has now picked up this fun behaviour, too. Do these behaviours stick with dogs once they are learned, or is he doing it because he's just joining in with the labs because of some social thing? Any of you had any luck reducing or eliminating these behaviours in your dogs?