My first dog was named Purzel by my parents. My second dog, bought when I was 1 year old in 1978, was named Gustav, but I called him Doody. He was already over a year old at the time.
In 1995 he died and we bought a replacement dog born the day before, called her Diana (after Diana, Princess of Wales). I call her Dog. But I rarely see her these days.
Purzel is just a funny name for a funny dog. Gustav is a typical name for the Berlin region (calling the dog loudly would make older people look around). Diana was a good name for a useless but pretty pet, we thought.