Not sure where else to ask this. Google is failing me. My little sister adopted a new puppy recently. It's a little over three months old and we've had it for two months. A week ago the puppy tried to steal our bigger, older dogs food and the bigger dog attacked the pup pretty ferociously. We caught them so no harm was done but the puppy was definitely freaked. The two were back to playing with each other within a day. Now all of a sudden today (a week after the previous incident.) the big dog attacked the puppy twice without any reason. Why would it do this? Possibly helpful info: The big dog is a lab-shepherd mix. About 7 years old. The puppy is a mix of everything under the sun. Only breed we can identify is terrier. Both are female. The big dog also did not eat it's food today and only ate a little the day before.