Survival
Survival is the Ability used to traverse and survive in wilderness environments. It covers the basic rudiments of outdoor survival, such as finding shelter, finding fresh water, and gathering food, as well as tracking, navigation, and handling animals.
Survival Dramatic Rules
Survival
Most of the time, it can be assumed characters traveling or camping in the wild have taken sensible precautions to keep from starving, dehydrating, or being gnawed on by wildlife. When characters haven't prepared for being thrust into the wilderness, or are trying to forge their way through particularly hostile environments, a simple ([Intelligence or Wits] + Survival) roll is sufficient to take care of the necessities of life—food, water, shelter. The difficulty is, as usual, determined by the harshness of the environment; trying to provide for a handful of unskilled individuals in addition to oneself is likely to raise the difficulty.
It's generally not fun to outright kill players' characters in response to failed Survival rolls; instead, treat failure as opportunity to introduce interesting plot complications. Perhaps the only apparent source of fresh water is a mountain pool... right at the mouth of a tyrant lizard's lair. Perhaps a poorly-weathered sandstorm injures a hired guide, or inadequate shelter results in disease-carrying insects descending on the travelers. Perhaps hostile locals appear once the characters have finally secured some game, to contest them for it.
Tracking
Tracking (and avoiding trackers) is also a Survival action. Tracking is a contested action—(Wits + Survival) for the party attempting to cover their tracks, against (Perception + Survival) for the tracker. The terrain might inflict penalties on one party or the other, if it is particularly easy to track in, or to avoid leaving tracks in.