{3}{G}: Look at the top card of your library. If it's a creature or planeswalker card, you may reveal it and put it into your hand. If you don't put the card into your hand, put it on the bottom of your library.
The ability of Vivien’s Grizzly has you put the card on the bottom of your library if you don’t put it into your hand for any reason, whether it’s not a creature or planeswalker card or whether you choose not to put it into your hand.