Our first four cats never cleaned each others ears.
They didn’t bond with each other.
Then, when Nardo was alone, the last cat standing, I found Bruwyn the kitten in the rain.
He bonded with Nardo, and tried to clean his ears.
Nardo freaked out, thinking it was an attack.
When we got Myst, she and Bruwyn cleaned each others ears.
And tried to groom Nardo’s.
Over time, he let them, and then would poke his head at them while they groomed themselves.
When he died, Bruwyn and Myst cleaned his ears, a final sign of respect to their mentor.