I have a four year old female jackrussel who is usually well behaved and nice to people. However the ther day I asked my mom to take care of her (we live with my mom and another room mate) while I was working. My mom asked the room mate to let my jrt out and when he went to let her out of my room shegrowled at him. He tried to approach her and she nipped at him. So then my mom tried to get her and she nipped at my mom. Then tonight my moms bf was playing with her as usual and she snipped at him. Does anyone know why she could be doing this?