My cat keeps opening his mouth wide for a couple of seconds, he has water and doesn’t seem to be thirsty but we just moved into a new house?
Opening his mouth wide in a yawn? Cats can and do yawn. If he is sniffing around the house and opens his mouth and makes a weird face, thats normal too. Cats have an organ on the roof of their mouth that helps them smell things, and making a funny face after sniffing something is a normal reaction.