It is not letting me rename my pets. Why?!?!?!?

This was mentioned in the tutorial, as well as the FAQ:

"You can give a name to any Nameless pet by clicking "Rename" button near the name in the pet profile.
Please be aware that pets get used to their names and you won't be able to rename them by your wish. A Puma who was called Kitty for several years won't understand a Beastlord who starts to call her Flaming Sunset.
You can use Amnesia Potion from the Premium Shop to make a pet forget its name and give it a new one."

Ok, sorry thanks. That is sort of wierd though. You should be able to change their name as you please.

Does your pet have a name already and you're trying to give it a new one? In order to give pets new names you must use an Amnesia Potion on them so they forget the name they already have.

The reason for this: If you call a dog Jack his entire life and then suddenly start calling him Charlie he won't respond to being called Charlie since he associates himself with the name Jack.

Edit:: Looks like I was too slow :P

It actually makes sense as it is explained. It would be the same thing for real animals, and even people.

E: Drat, now I'm the slow one. :P