Reasons for big dogs to attack small dogs:

1. Frightened. The puppy will jump around in front of the big dog, frighten the big dog or repeatedly anger the big dog, and then it will attack the puppy.

2. Strong territorial awareness. In order to show their leadership status, older dogs will show their teeth and show aggressive behavior towards smaller dogs.

3. Emotional transfer. The big dog is locked up at home and has nowhere to vent its energy, so it can only attack the smaller dog to get some exercise.

4. Physical discomfort. If a dog is usually relatively docile, but suddenly becomes aggressive for no reason, it may be due to physical discomfort or pain, which may cause the dog to become irritable.

How to deal with big dogs attacking small dogs:

1. Human intervention. Pour a bucket of water or a hose over them to immediately break up their fight and make them forget about their animosity toward each other.

2. Temporarily separate. Isolate the big dog and the small dog separately, do not let the two dogs come into contact for the time being, and feed and water the big dog and the small dog separately.

3. Enhance feelings. Increase the time the two dogs spend together, and play with toys with them to increase their affection.

4. Do ligation. For the dominance-fighting behavior among male dogs, testicular removal surgery can slow down the occurrence of this behavior.