hurn

Hey guys, i have a little problem with pet's Growl ability. I had a cat pet and at lv20 i taught him Growl ability from a trainer. Then i changed pet to a wolf lv 20 and he didn't have Growl. I went to the trainer to see that next Growl i'll be able to learn is at lv30 and it's rank 4 Growl. Anyone has an idea what's going on?