From the Super Mario Wiki
A Green Yoshi sniff-sniffing near an apple

Sniff-Sniffing[1] (sometimes referred to as simply "sniffing") is a basic special move that is found in Yoshi's Story. All the Yoshis in the game have the ability to sniff-sniff.

To use it, the player must press and hold the R Button button to make the Yoshi start sniffing the ground. The Yoshi can move while sniff-sniffing, but he does so more slowly than normal, attempting to detect something valuable to him in the ground. When the Yoshi gets closer to something special, he starts to sniff faster. Getting close to a secret causes a ! icon to pop up above the Yoshi's head, indicating that the secret is nearby. When the Yoshi is on the secret spot on the ground, he gets excited and signals the player by yelping and waving his arms. To retrieve the secret, the player must then make the Yoshi ground-pound the spot where the hidden treasure lies.


  1. ^ Yoshi's Story instruction booklet, page 12.