Fly-Catching
Some dogs can develop a condition called “fly-catching” where they repeatedly open and close their mouths as if trying to catch an imaginary fly. This behavior is most commonly seen in small breeds such as the Chihuahua and Pomeranian.
The exact cause of this behavior is not known but it may be related to epilepsy or other neurological disorders. It is important to consult with a veterinarian if you notice this behavior in your dog, as it can be an indication of an underlying health problem.