Nate near a Yak.

Yaks are animals that appear in the sixteenth chapter of Uncharted 2: Among Thieves.

Chapter 16 - Where Am I?

When Drake is following Tenzin through the Tibetan Village, he will come across a few yaks. The player can pat or stroke the yaks by pressing PlayStationTriangle or PlayStationSquare when near them.if pressing triangle whilst behind, drake will wave his hand near his face as if there is a stench (this will not affect the beast mode medal) . If the player does this to all four Yaks they earn the Beast Mode medal.