I've hit 2 dogs and a cat.
I was driving my mum in her Fiesta when the cat ran across the road, no time to hit the brakes, heard the thud

as it was hit by the diff, and then saw it carry on running.
1st dog was also in same car; dog ran out of screened drive into the rear LH wheel and concussed itself... took the owner, a young lad round to his parents (wouldn't do that now...) who came round later to say dog was Ok and to thank me for stopping and reporting it etc.
2nd dog, at the exact same point on the same road, came running out of the same drive as before and hit it on the side, cracking my no. plate in the process; the dog rolled over and carried on running. at the time (14yrs ago) I didn't know you had to report it, so didn't.