Hi I have a 8 month old beagle male named Petey...he has been having some growling issues lately with my other puppy, who is also 8 months old(have grown up together) she is a siberian/shepard,and spayed as well,Petey is not yet...anyways whenever I bring out my pet guinea pigs Petey goes crazy licking them,etc,he loves them,no aggression whatsoever,but when my other puppy Keira trys to come and see them Petey starts growling at her as if to say,Hey,these are my babies,don't come near.When I try to comfort Keira,to let her know she's not doing anything wrong ,Petey comes right up to us and growls and barks at her as if to say,this is my mommy,and don't come near her...I have been disciplining him when he does this,putting him in his crate for time out.Does anyone know why he is doing this behavior?,and it seems to be only in the evening when I let them in for the night.Please Help,Thank you.Concerned,Heidi