What kind of creature could have left this mark ?

Sadly we woke up this morning to this large bite upon our male cat. He is able to walk, appetite diminished but he eventually ate. Overall his mood seems somewhat normal. Waiting on the next available cat vet appt, which is tomorrow at 8am.

The second photo was taken hours later. There is blood due to constant licking.

Does anyone recognize what kind of animal could have left this mark ? Another cat ? We do live in an area where opossums and raccons used to come by frequently but not much anymore. There are occasional coyote sightings by neighbors.

We are in the San Francisco, East Bay area. Any shared knowledge would be appreciated. I'll give updates after the appointment.