It looks like it is for warden only. Looks like the warden class will be able to capture/train animals and use as a combat pet.
they said it in twitch, it stays until it dies, you can heal it and you can buff it, if it dies, you need another ulti to cast it again
In Asheron's Call the mobs could level. There were these little bunnies all over. Level 126 characters would debuff to aggro this one bunny over and over to get it to kill them (which took forever) to level the little thing. No one was more hated than someone who killed that little bunny.
Then again, the most dangerous creature in the game was a little white bunny...