This cannot be unlocked till the third island. You will get this as you progress through the game as it cannot be missed. You will see a trail leading away from a flower that will attract your wolfimpa towards it.
You will eventually find one down a crevice between to points you need to get across. Send one of your Mummimpa's over the crevice to the other side and it will block the scent trail unlocking you this achievement.