Play and serious
Is it easy to tell the difference between play fighting and serious fighting. Millie and Cleveland are chasing each otehr about and he'll have a bop at her (no claws) and she'll do the same. There will be an occasional growl when someone has had enough. Is this just playing about or is it dangerous to them? I was worried someone would get hurt.
There are many intelligent species in the universe. They are all owned by cats!