I have a Jack-a-poo, Bohdi , who is around 2 years old, i adopted him about a year ago. In the begining he was very good with other dogs, the only problem i had was him urinating on everything but i corrected that in two weeks. My sister has a Giant black dog(male) who is very submissive and all he would like to do is play with Bohdi but every time He walks by Bohdi growls sometimes even snaps, everyday all day. we have another dog which is female but we don't have a problem Bo loves her. Also now when we walk he lunges at the dogs barking through the fences ,growls, he gets quite hostile. I have tried many ways to correct him but i don't seem to be having much success. . . . Any Ideas? Thanks!!!