I had a full-grown Doberman follow my mean-ass cat home one day,and follow her into the house after the cat scratched at the door to be let in. Lived on a 15 acre former horse farm out of the city with no neighbors. I have no idea HTH those two got together and decided to be friends.
Especially the cat,who just moved in one day when I opened the door. She wasn't friendly with anything until that Dobie showed up. They were sleeping together and grooming each other within a day,and the cat was still snarling and striking at ME if I tried to touch her.