I feel like naming an animal and keeping that name is more of a fluid process, than one set in stone.
For example, when we got a cat as a child, he was originally named "Pooh Bear", but ended up with the name Coat. He really enjoyed riding on our Chihuahua's back as a kitten and he looked like her coat. :)
Either way, it seems that no matter what you name your new pet, and no matter what kind of animal it is, that name will always either morph into something else or they will gain an obnoxious amount of nicknames.
Check out the list below for the evolution of some people's pet's names.