(If you want to skip to the actual story/bites, just read the 3rd paragraph)
We've had our two greyhounds for over 3 years now and we absolutely love them! They are littermate, the male being Kane and the female Karen. Kane has always displayed some dominance over Karen and our two smaller dogs (which pretty normal to have a dominant dog in any "pack"), but has never showed anything that would concern me while IN THE HOUSE. BUT when on walks he can turn into what seems a whole different dog.
Basically if Kane gets excited for any reason (usually when he sees a deer or something like that) he will growl and nip/bite Karen or bite the leash. This excited nippy behavior, from what I've read many times on both this forum and other resources many years ago, is a pretty normal off the track greyhound behavior (and is one of the main reasons for why they wear muzzles while racing or while being with other dogs). He's done this since I've adopted him when he was only 9 months old. With some correction (just a sharp "NO!" and if he continues I will separate them, turn around, and walk home) he USUALLY will calm down and continue the walk like nothing happened. He also was a pretty mouthy dog when we got him, and likes to fleabite and mouth people when he's happy, but he rarely does this anymore. As he's aged, his mouthy behaviors slowly got better. Thats until now...
A 3 months or so ago my grandma came to visit and took both they grey on a walk, (which she has done many times before!) and came back and told me that Kane bit her in the stomach! Ofcourse I was in disbelief and figured that she mistook fleabiting as aggression, but it still concerned me that he broke her skin though a layer of clothing. He also did it a second time to her, and after that we only walked him with a muzzle. Since then, we got a fenced-in yard and only walk the dogs on occasion. A new behavior that Kane has picked up on walks now in showing interest in cars (remember, he's nearly 4 years old now and he's never once cared about cars going by). A couple days ago he got excited and acted like he wanted to chase a few cars that went by, but didn't go crazy lol. Today though, he showed that same interest in cars. On our way back to the house, a car went by that came particular close to us, and with out warning he growled and bit my really hard on my arm, enough to break my skin and cause me to bleed pretty bad. Obviously I was shocked, and in reaction I just yanked his leash away from me and screamed "no" at him. He didn't really seem to care though, and kept focusing on the car driving down the road. He was walking slowly being me when he did this, so I didn't really see his body language or any warning before hand.
Other than this, Kane is a really really sweet dog! He is what many people would consider to be the perfect dog - he is super chill, laid-back, loves to be loved, loves his people, and is soooooo sweet! Our family has had many dogs in the past (mostly rescues), and we can all agree that Kane is a really easy dog. Despite these odd incidences, he's good greatly out weighs the bad and I will always love him to bits and pieces, but I'd really like to know why he is doing this? Has anyone else experienced this type of behavior before, what can I do better in a situation like this, and why suddenly doing this? I s it out of anxiety, fear, dominance, and/or aggression?