[Austin's Mama]

Austin is 1 and a half years old and not neutered. We also have a 9 year old lab, Jake, that is as sweet as can be (he is neutered). They have been "brothers" since Austin was practically born and best of friends. However, for the last 2 months or so Austin sits at their doggy door inside the house and refuses to let Jake inside. Its so sad! Jake sits outside crying wanting to come inside and when he attempts to come inside, Austin becomes a "gremlin" and literally attacks Jake! He does this AWFUL growl and goes for Jakes throat and HANGS on!! He does this every single day! What in the world is going on??!! Why is he suddenly such a bully??!!